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10 June 2021, Volume 42 Issue 6

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Cover and Content of Chemical Journal of Chinese Universities Vol.42 No.6(2021)

2021, 42(6):  1-12. 

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Supramolecular Interactions Induced Chiral Assembly of Plasmonic Nanoparticles with Enhanced Optical Asymmetry

LIU Dongsheng

2021, 42(6):  1619-1621.  doi:10.7503/cjcu20210293

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Science has recently reported the important progress of chiral nanomaterials achieved by LIU Kun’s group from Jilin University and coworkers. Supramolecular interactions of gold nanorods（NRs） with human islet amyloid peptides catalyze their assembly into metallic superstructures with unusually high cholesteric order. Contrary to current theories， the transition from individual NRs to long straight helices leads to increase of g-factor（up to 0.12） by 4600 times. This work establishes the link between the liquid crystals and chiral inorganic nanostructures； provides unifying design principles for organic and inorganic optically active media and opens new modalities for drug discovery for amyloid diseases.



Review

Research Progress of Catalytic Synthesis of Carbon Nanomaterials by Layered Double Hydroxide-based Catalysts

DING Zhongzhen, LI Tian, LI Changming, ZHAO Yufei, SONG Yu⁃Fei

2021, 42(6):  1622-1647.  doi:10.7503/cjcu20200874

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Carbon nanomaterials are a class of functional materials that provide a robust platform in the deve-lopment of energy storage， heterogeneous catalysis， high-performance compounding， biomedicine， and other fields. Therefore， the effective control of synthesis of carbon nanomaterials is of great significance to the deve-lopment of related fields. Layered double hydroxide with the precisely-controlled both type and content of host layer metal cations can form metal nanocatalysts with high dispersion and high stability in different types， densities and particle size distributions after roasting and reduction. The obtained metal nanocatalysts can be further applied to the efficient catalytic growth of various types of carbon nanomaterials. In addition， the factors such as reaction conditions and reactors also have an effect on LDH-based metal nanocatalysts-catalyzed growth of carbon nanomaterials. This article summarizes the research work in the field of LDH-based metal nanocatalysts preparing carbon nanomaterials from the aspects of the controllable preparation of catalysts， the structure regulation of carbon nanomaterials， and the application of carbon nanomaterials prepared by LDH-based catalysts， and clarifies that the controllable preparation of catalysts is the core means for the controlled synthesis of carbon nanomaterials， which points out the direction for the next step of LDH-based catalyst controlled synthesis of higher performance carbon nanomaterials. In addition， this article also combines the progress of scientific research in recent years in the fields of light， electricity， as well as photothermal catalysis， and looks forward to the research prospects of growing carbon nanomaterials based on new LDHs nanostructures.



Research Progress of Quasi-two-dimensional Perovskite Solar Cells

YUE Shengli, WU Guangbao, LI Xing, LI Kang, HUANG Gaosheng, TANG Yi, ZHOU Huiqiong

2021, 42(6):  1648-1671.  doi:10.7503/cjcu20200863

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Quasi-two-dimensional（2D） perovskite（organic-inorganic hybrid） has attracted enormous attention in solar cells due to its excellent stability， crystallinity and photoelectric properties. In contrast to the 3D perovskite， the unique layered crystal structure endows some extraordinary properties of quasi-2D perovskites， which is due to the intercalation of organic spacer cations（OSC） into the 3D framework. （1） The multilayer quantum wells create the anisotropic photoelectric properties. （2） The spacer cations change the environment of the clusters in precursor solution to achieve high-quality perovskite films. （3） The hydrophobic spacer layers with inhibition of ion migration realize excellent stability of quasi-2D perovskites films. However， the photoelectric transformation efficiency（PCE） of quasi-2D perovskite solar cells（PSCs） is still far less than that of 3D counterparts due to quantum confinement effect， dielectric confinement effect， non-preferred crystal orientation and random phase distributions of quasi-2D perovskites films. In order to solve these problems and achieve the balance between the PCE and stability of solar cells， it should be better understood of 2D perovskites from the crystal structures， photoelectric properties as well as the device performances. In this paper， we first introduce the crystal types including the （100）， （110） and （111）-oriented structures. On this basis， the preferred orientations（out-of-plane and in-plane） and uniform/graded phase distributions are overviewed for the most studied （100）-oriented structure. To the understanding of the nucleation and crystallization processes of quasi-2D perovskite films， we then discuss the preparation methods from the perspective of one-step and two-step film-casting， respectively. Furthermore， we summarized the extensive researches on quasi-2D-PSCs and analyzed a series of significant results. Meanwhile， we highlight internal mechanism of quasi-2D perovskites stability and summarize superior long-term stability of quasi-2D perovskites and 3D/2D heterojunction perovskites. Last but not least， we further looked ahead to research trends in the future， such as： phase purity of 2D perovskites thin films， graded phase 2D perovskites thin films， modified interface， design of new organic spacer cations， 3D/2D heterojunction perovskites.



Recent Progress in Organic Single Crystal Integrated Circuits

LIN Chengce, PENG Boyu, LI Hanying

2021, 42(6):  1672-1684.  doi:10.7503/cjcu20200902

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Organic integrated circuits have great advantages in cost efficiency， flexibility， and portability compared with traditional silicon-based integrated circuits. With improved molecular packing and mobility， organic single crystals show better electrical performance. Integrated circuits based on organic single crystals thus show abundant research value and potential in applications. This review introduces the recent progress of organic single crystal based integrated circuits， with specific focus on the work related to basic logic gate circuits. Furthermore， pioneering attempts to prepare integrated circuits using organic single crystals are summarized. Finally， the challenges that have been met and prospects of organic single crystals in integrated circuits are discussed.



Discussion of the Key and Common Academic Questions in Absolute Configuration Determination of Chiral Compounds

WANG Xuxin, ZHU Huajie

2021, 42(6):  1685-1693.  doi:10.7503/cjcu20200726

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Possible calculation traps， which frequently appeared in absolute configuration determinations， are discussed here. These include （1） how to avoid falling into the traps during using various software in calculation procedure， （2） how to use simplified models to representative original chiral molecules， and （3） to find limitation of some software and the premise of their application. Some suggestions are provided for the resear-chers who are not very familiar with the calculation procedures to avoid falling into the traps during the calculations of optical rotation（OR）， electronic circular dichroism（ECD）， vibrational circular dichroism（VCD）， and ¹³C nuclear magnetic resonance（NMR） spectra. Some examples are given for readers to understand the details in the absolute configuration determination procedures.



Progress of Graphene Oxide/Polymer Composite Hydrogel

LI Peihong, ZHANG Chunling, DAI Xueyan, SUI Yanlong

2021, 42(6):  1694-1703.  doi:10.7503/cjcu20200869

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Graphene oxide（GO） is a popular two-dimensional material with excellent mechanical properties， good water dispersibility， non-toxicity， and good biocompatibility， and its surface has a large number of oxygen-containing functional groups. Therefore， GO is an ideal hydrogel raw material. Hydrogel is a multi- element system with a three-dimensional network structure and water as the filling medium. The introduction of GO into the hydrogel system can improve the mechanical properties of the hydrogel and enrich its stimulus response types. At present， GO hydrogel has excellent performance in many fields such as high strength， adsorption， self-healing materials and sensors， and has become one of the research hotspots. The research of GO hydrogel has a history of ten years. In this review， the preparation methods of GO hydrogels are summarized， including acidification and the addition of polymers， small organic molecules or ions as crosslinking agents. Among them， GO/polymer composite hydrogels prepared by physical mixing and chemical crosslinking and polymerization methods are the most common. The response mechanism and research progress of smart GO hydrogels are summarized in terms of photo-thermal response， pH response and self-healing. The application prospects of GO hydrogels in high strength hydrogels， biomedicine science， smart materials and sewage treatment are reviewed.



Inorganic Chemistry

Synthesis and VOCs Adsorption Properties of Hollow Carbon Nanospheres

WANG Hongning, HUANG Li, SONG Fujiao, ZHU Ting, HUANG Weiqiu, ZHONG Jing, CHEN Ruoyu

2021, 42(6):  1704-1715.  doi:10.7503/cjcu20200864

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Under alkaline conditions and without using surfactants， primary spherical siliceous particles were produced through St?ber method with tetraethyl orthosilicate（TEOS） and tetrapropyl orthosilicate（TPOS） as silica sources， then phenolic resin-silica composites were obtained by co-condensation of phenolic resin（isobenzene diphenol and formaldehyde） and the hydroxyl groups of silica. Hollow carbon nanospheres（HCNSs） were obtained after high temperature carbonization and acid etching of the phenolic resin-silica composites. By adjusting the molar ratio of TEOS/TPOS， a series of HCNSs with good monodispersity and adjustable particle sizes and wall thicknesses was obtained. The particle sizes and wall thicknesses are in the range of 280—430 nm and 15—63 nm， respectively. HCNS synthesized only with TPOS as silica source（HCNS-0/4） has a larger particle size（426 nm）， wall thickness（63 nm）， higher specific surface area（1216 m²/g） and pore volume（0.508 cm³/g）， and the best VOCs adsorption performance. For HCNS-0/4， the static n-hexane， toluene and oil vapor adsorption capacities are 2.02， 1.42 and 0.926 g/g， respectively， and the dynamic n-hexane and toluene adsorption capacities are 2.01 and 1.37 g/g， respectively， which are much higher than those of commercial activated carbon.



Exploring Organic Structure-directing Agents Used for SAPO-34 to Synthesize SSZ-13

WANG Lei, SUN Tantan, YAN Nana, MA Chao, LIU Xiaona, TIAN Peng, GUO Peng, LIU Zhongmin

2021, 42(6):  1716-1722.  doi:10.7503/cjcu20200855

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The aluminosilicate zeolite SSZ-13 and zeolitic silicoaluminophosphate molecular sieve（SAPO MS） SAPO-34 have been widely used in commercialized catalytic applications， such as the methanol-to-olefins（MTO） process and the selective catalytic reduction of NO_x with NH₃（NH₃-SCR）. Nowadays， a variety of commercialized organic structure-directing agents（OSDAs） have been utilized for preparing SAPO-34， while the OSDAs for synthesizing SSZ-13 still mainly relies on the classical N，N，N-trimethyladamantammonium hydroxide（TMAdaOH）. Therefore， it is of great significance to seek for the suitable OSDAs， which can direct the synthesis of SSZ-13 with higher cost performance and appliable high silicon-to-alumina ratio（SAR）. Herein， three OSDAs used for preparing SAPO-34［diisopropylamine（DIPA）， dipropylamine（DPA） and n-butylamine（nBA）］ were successfully employed for synthesizing SSZ-13 by partial replacing the expensive TMAdaOH with or without the assistance of seeds. Systemic investigation focused on SSZ-13 preparation was explored by powder X-ray diffraction（PXRD） and solid-state nuclear magnetic resonance（ss-NMR） analyses. As a result， the as-synthesized SSZ-13 zeolites possess a tunable range of SARs（11―22） and Cu-SSZ-13 catalysts show excellent NH₃-SCR performance compared with commercialized ones. The crystallization mechanism of SSZ-13 synthesized by DIPA and TMAdaOH were also studied and the addition of DIPA would accelerate the crystallization process， improve the yields， and prevent the formation of amorphous phase. The work presented here might provide new insights for identifying more efficient and commercialized OSDAs for preparing SSZ-13 with tailored properties.



Synthesis and Photocatalytic Degradation Activity of Two Inorganic-organic Hybrids Based on Keggin-type Heteropolyacids

ZHAO Xue, ZHANG Ange, TIAN Hongrui, WANG Henan, HUO Haiyan, LIU Shuxia

2021, 42(6):  1723-1729.  doi:10.7503/cjcu20200845

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Two inorganic-organic hybrids based on Keggin-type heteropolyacids with the chemical formula ｛［Cu₂（4，4′-bipy）₄（H₂O）₄］（SiMo₁₂O₄₀）·18H₂O｝_n（1） and ｛［Cu₂（4，4′-bipy）₄（H₂O）₄］（PMo₆W₆O₄₀）·18H₂O ｝_n（2）（bipy=bipyridine） were prepared. The single crystal X-ray analysis shows that the two compounds are isostructural， in which the Cu²⁺ is six-coordinated， ligated by four N atoms from four 4，4′-bipy and two O atoms from the two water molecules， forming a 2D cation layer ［Cu（4，4′-bipy）₂（H₂O）₂］_n²ⁿ⁺. Keggin-type heteropolyanions are arranged between the 2D cation layers by electrostatic interaction with coordination cations ［Cu（4，4′-bipy）₂（H₂O）₂］_n²ⁿ⁺. These compounds are characterized by infrared spectroscopy， powder X-ray diffraction and solid ultraviolet-visible diffuse reflectance spectroscopy. The degradation activity of synthetic compounds on the water-soluble dye methylene blue was researched. The experimental results indicate that the two compounds exhibit significant photodegradation activity for methylene blue， and the catalytic mechanism is discussed.



Synthesis of Three-dimensional Ordered In₂O₃ Nanowire Arrays and the Effect of Nanostructure Order on Gas Sensitivity

SUN Hao, GONG Jie, YANG Yan, WANG Xinqing, CHEN Huidong

2021, 42(6):  1730-1735.  doi:10.7503/cjcu20200782

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Three-dimensional ordered In₂O₃ nanowire arrays were synthesized using SBA-15 silica as hard template with replication technology， and then the two In₂O₃ samples with different particle sizes were separated with centrifugal separation technology. The crystal structure， grain size， morphology and bandgap of both samples were characterized by means of XRD， SEM and UV-Vis spectroscopy. Both In₂O₃ samples present three-dimensional nanowire array structures， which are orderly assembled with the spherical In₂O₃ particles with grain size of 12 nm. The diameter and interwire distance of In₂O₃ nanowires is about 12 nm and 2 nm， respectively， while the bandgap of In₂O₃ nanowires with the larger particle size is slightly larger than that with the smaller particle size. The sensitivity of In₂O₃ nanowires with the larger particle_{size reaches up to 50. 6 to the ethanol gas with volume ratios of 100×10^-6 in air at 320 ℃， which is higher than that with the smaller particle size. Finally， the gas-sensing performance of In2O3 nanowires with the larger particle is obviously better than those of the similar nanoparticles and mesoporous nanostructures， indicating that the order degree of In2O3 nanowire greatly affects the gas-sensing properties of nanostructures.}



Analytical Chemistry

Silicon-based Micro Gas Chromatographic Column Using Metal-Organic Framework Material ZIF-8 as Stationary Phase

ZHAO Yangyang, LIU Qiyong, CHEN Boxin, ZHAO Bin, ZHOU Haimei, LI Xinxin, ZHENG Dan, FENG Fei

2021, 42(6):  1736-1741.  doi:10.7503/cjcu20200867

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A semi-packed column embedded elliptical cylindrical posts was fabricated based on micro-electro-mechanical system（MEMS）， and metal-organic framework（MOF） material ZIF-8 was synthesized by hydrothermal method and coated on the inner wall of the micro channel as the stationary phase. The performance test is performed under constant temperature of 30 ℃. The micro gas chromatography（GC） column using ZIF-8 material as the stationary phase can achieve the baseline separation of the methane， ethane and propane（C1—C3） in 75 s， with the resolution between the methane and ethane of up to 2.23， 99% higher than the micro GC column coated with mesoporous silica. The relative standard deviations of the peak areas of methane and ethane， and resolutions between methane and ethane were all less than 3%. The above results demonstrated the potential of the micro GC column using ZIF-8 as the stationary phase for use in portable analysis equipment for the real-time analysis of oil field gas.



Organic Chemistry

Chemical Constituents of New Steroidal Saponins from Allium chinense G. Don

YANG Yiran, YAO Hua, YAN Jianghong, SUN Zhiheng, ZHANG Yu, FANG Xueqing, LI Xuwen, JIN Yon⁃Ri

2021, 42(6):  1742-1753.  doi:10.7503/cjcu20200905

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Six new steroidal saponins were isolated from 98% ethanol extract of Allium chinense G. Don. Through spectral data as well as physical and chemical analysis， they were identified as 5α-cholano-22，16- lactone-3-O-β-D-glucopyranosyl-（1→2）-［β-D-glucopyranosyl-（1→3）］-β-D-glucopyranosyl-（1→4）-β-D-galacopyranoside（1）， 6-ketone-5α-cholano-22，16-lactone-3-O-β-D-6-xylopyranosyl-（1→4）-［α-L-arabinopyranosyl-（1→6）］-β-D-glucopyranoside（2）， （25R）-26-O-β-D-glucopyranosyl-5α-furostane-3β，26-diol-3-O-β-D-glucopyranosyl-（1→2）-［β-D-glucopyranosyl-（1→3）］-β-D-glucopyranosyl-（1→4）-β-D-galacopyranoside（3）， （25R）-6-ketone-26-O-β-D-glucopyranosyl-5α-furostane-3β，22α，26-triol-3-O-α-L-xylopyranosyl-（1→4）-β-D-glucopyranoside（4）， （25R）-6-ketone-5α-furostane-3β，22α，24β，26-tetraol-3-O-β-D-xylopyranosyl- （1→4）-［α-L-arabinopyranosyl-（1→6）］-β-D-glucopyranoside（5） and （25R）-5α-furostane-2α，3β，22α，26- tetraol-26-O-β-D-glucopyranoside（6）. To the best of our knowledges， the sapogenin skeletons of compound 1 and compound 2 were isolated from natural products for the first time. The cell proliferation-toxicity test kit（CCK-8） was used to explore the PC12 cells hydrogen peroxide induced the protective effect of oxidative damage. The experimental results showed that compound 3 had a significant protective effect on cell oxidative damage induced by hydrogen peroxide.

? Supported by the Science and Technology Development Plan of Jilin Province, China(No.20200404138YY).



Chemical Biology

Synthesis of 2-（2-Hydroxy-3-methoxyphenyl）-C₆₀ and Its Application for Sensing of Cauliflower Mosaic Virus 35S Promotor

WU Yangyi, CHEN Jianping, Ai Yijing, WANG Qingxiang, GAO Fei, GAO Feng

2021, 42(6):  1754-1760.  doi:10.7503/cjcu20200744

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A new pyrrolidine derivative of 2-（2-hydroxy-3-methoxyphenyl）-C₆₀ pyrrolidine derivative（HMP-C₆₀） was synthesized by a 1，3-dipolar ［3+2］ cycloaddition reaction， and the chemical structure of the product was characterized by means of infrared spectroscopy， ultraviolet absorption spectroscopy， elemental analysis and LC-MS. The HMP-C₆₀ was then immobilized on the surface of the glassy carbon electrode by coating. Then， on the basis of the strong coordination between Zr⁴⁺ and the oxygen-containing groups， Zr⁴⁺ was used as a bridging reagent to tether probe DNA with the 5′-end modified phosphate group on the surface of the HMP-C₆₀ modified electrode. Thus， an electrochemical DNA sensor based on HMP-C₆₀ modified electrode was constructed. Using ［Fe（CN）₆］^3-/4- as the electroactive probe， the electrochemical characterization of different modified electrodes was carried out， and the performance of the sensors for analyzing the characteristic DNA fragments of cauliflower Mosaic virus（CaMV35S） promoter was investigated by impedance method. The experimental results showed that in the concentration range of 1.0×10^-13—1.0×10^-9 mol/L， the electron transfer impedance changes（ΔR_et） of the biosensor had a good linear relationship with the logthrim values of the target DNA concentrations（lgc_S2）， and the detection limit was estimated to be 4.0×10^-14 mol/L（S/N=3）. The biosensor can effectively identify complementary sequences， base-mismatched sequences and non-complementary sequences， showing a good selectivity.



Colorimetric Determination of Sarcosine with Carbon Quantum Dots as Mimetic Peroxidase

SHU Xin, WANG Di, YUAN Chunling, QIN Xiu, WANG Yilin

2021, 42(6):  1761-1767.  doi:10.7503/cjcu20200719

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Water soluble carbon quantum dots（CQDs） were prepared from fruit skin. Transmission electron microscopy（TEM） analysis showed that the average particle size of the CQDs was 2.4 nm. Fourier transform infrared spectroscopy（FTIR） revealed that the surface of CQDs was predominated in oxygen-containing functional groups. The obtained CQDs could catalyze the H₂O₂-mediated oxidation of 3，3'，5，5'-tetramethylbenzidine（TMB） to produce the corresponding blue oxidized product（ox-TMB）. Thus， a simple method for the detection of H₂O₂ was established. Under the conditions of pH=3.5， temperature of 40 °C， 1.0 mmol/L TMB and incubation time of 15 min， the absorbance of ox-TMB increased linearly with the increase of H₂O₂ concentration in the range of 5.0—100 μmol/L， and the detection limit（3σ/k） for H₂O₂ was 3.0 μmol/L. Given the fact that H₂O₂ was one of the products of sarcosine oxidase（SOX）-catalyzed sarcosine oxidation， a method for the indirect detection of sarcosine based on CQDs-catalyzed and H₂O₂-mediated TMB oxidation was also deve-loped. The increase of ox-TMB absorbance enabled the sensitive determination of sarcosine in the range of 0.5—350 μmol/L， and the detection limit sarcosine was calculated to be 0.3 μmol/L. The method exhibited its potential application in the detection of sarcosine in human urine samples with the recovery of 94%—99%.



Fabrication of Biosensor Based on “Beads-on-a-String” Shaped Composite Nano-assembly Modified Screen Printed Electrode

XU Mengyi, HUANG Xuewen, LI Xiaojie, WEI Wei, LIU Xiaoya

2021, 42(6):  1768-1775.  doi:10.7503/cjcu20200700

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An amphiphilic random copolymer poly（AAPBA-co-FMA-co-HEMA） （PAFH） was synthesized with 3-acrylamidophenylboronic acid（AAPBA）， furfuryl methacrylate（FMA） and 2-hydroxyethyl methacrylate（HEMA） as monomers. Thereafter， the functional polymer covalently grafted carbon nanotubes（PAFH-CNTs） was fabricated via Diels-Alder reaction between PAFH and carbon nanotubes（CNTs）. They were co-assembled to form composite nano-assemblies（PAFH-CNTs NCs）. The morphology and stability of PAFH-CNTs NCs were measured by scanning electron microscope（SEM） and ultraviolet spectrophotometer. The results showed that PAFH-CNTs NCs has a zero dimensional/one dimensional（0D/1D） “beads-on-a-string” structure with long-term stability. Finally， PAFH-CNTs NCs were modified on the surface of screen-printed carbon electrode（SPCE）， and the horseradish peroxidase（HRP） was introduced to construct a biosensor to detect hydrogen peroxide（H₂O₂）. SEM， transmission electron microscopy（TEM） and electrochemical workstation were used to characterize the morphology and sensing performance of the biosensor. It was illustrated that PAFH-CNTs NCs could form a nanonetwork with high specific surface area on the SPCE surface. The constructed sensor has a good linear response to H₂O₂ within the range of 0.02—3.48 mmol/L， and the sensitivity and detection limit are 63.98 μA·（mmol/L）^-1·cm^-2 and 4.2 μmol/L， respectively. Furthermore， it also has excellent stability and selectivity， which has application value for testing actual samples.



Ultraviolet Absorbance of Saturated Structure in the Non-reducing End of Heparin/Heparan Sulfate Disaccharides and Its Application in Sequence of Heparin Oligosaccharides

LIANG Quntao, ZOU Qiang, LIN Jianghui, LIU Shutao, WEI Zheng

2021, 42(6):  1776-1784.  doi:10.7503/cjcu20200671

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It is well known that the saturated structure in the non-reducing end（NRE） of heparin/heparan sulfate（HS） oligosaccharides is lacking ultraviolet（UV） 232 nm absorbance（normally used for specific detection of C4―C5 unsaturated oligosaccharides）， which poses a significant challenge for structure analysis. However， we found that saturated heparin oligosaccharides can be detected at UV 232 nm with sufficient sensitivity in our previous research. In order to further study the UV 232 nm absorbance of the saturated structure， four saturated heparin disaccharides were prepared， and then their UV 232 nm absorptions were analyzed by ion-pair reversed-phase liquid chromatography ion-trap/time-of-flight mass spectrometry（RPIP-LC/MS-IT-TOF） with photodiode array detector. The results show that the saturated heparin disaccharides can be detected with sufficient sensitivity by absorbance at UV 232 nm， which still with 7%―40% of UV 232 nm intensity of heparin unsaturated disaccharides. It seems that the UV 232 nm intensity might be affected by the sulfate groups in the disaccharides. In addition， comparing to the common unsaturated heparin/HS disaccharides as references， the disaccharides with GlcNH₃⁺ residues also showed less sensitivity at UV 232 nm. Finally， we simplified the sequencing method of the N-unsubstituted dp6 oligosaccharides by a simple UV detection method， combined with pH 4.0 HNO₂ scission and RPIP-LC/MS-IT-TOF analysis. This strategy offers possibilities for sequencing at N-sulfated residues using alternative pH 1.5 HNO₂ scission.



Physical Chemistry

Moisture-assisted Crystallization of Inorganic Perovskite CsPbI₃ Film

LI Yanyan, DUAN Linrui, LUO Jingshan

2021, 42(6):  1785-1792.  doi:10.7503/cjcu20210228

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Moisture-assisted recrystallization strategy was used to improve the quality of CsPbI₃ film， and the influence of different relative humidity（RH） on the crystallization was investigated by studying the morphology， trap-induced recombination， and photovoltaic performance. The results showed that different from the CsPbI₃ films annealed at 0%RH with obvious grain boundaries， the ones at appropriate humidity show more compact binding between grains， which suppresses the nonradiative recombination. However， excessive humidity causes rougher surface which will affect the interface contact. By comparison， CsPbI₃ films annealed at 7%RH have significantly reduced trap density， increased carrier lifetime， and restrained nonradiative recombination. The photovoltaic performance test shows that the open circuit voltage（V_oc） and fill factor（FF） increase a lot and an efficiency of 15.28% is obtained.



Theoretical Studies on Pd-catalyzed Oxidative N─H Carbonylation to Synthesis of 1，3，4-Oxadiazole-2（3H）-one Heterocyclic Compounds

REN Ying, LI Changhua, WANG Tao, XUE Shanshan, ZHANG Tingting, JIA Jianfeng, WU Haishun

2021, 42(6):  1793-1800.  doi:10.7503/cjcu20210067

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A systematic mechanistic investigation was carried out for the Pd-catalyzed oxidative N—H carbonylation to synthesis of 1，3，4-oxadiazole-2（3H）-ones. The calculation results show the preferred cataly-tic cycle proceeds in steps through N1—H activation， CO insertion， N2—H activation， and reductive elimination. The N1—H activation proceeds in a concerted metalation/deprotonation mechanism， and following CO inserts into Pd—N1 bond forming a stable six-membered ring intermediate. Then the metallacycle intermediate undergoes the N2—H bond activation directly through a one-step reaction， and finally reduction and elimination occur to complete the entire catalytic cycle. The rate-determining step is CO insertion with a Gibbs energy of 102.0 kJ/mol. Furthermore， ligand effect and substituent effect are also been elucidated.



Facile Synthesis of Hollow Nickel Submicrospheres with Hierarchical Nano-structure and Its Catalytic Hydrogenation of Phenol

FAN Ye, HAN Huihui, FANG Yun, FENG Ruiqin, XIA Yongmei

2021, 42(6):  1801-1806.  doi:10.7503/cjcu20210046

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The nickel nanomaterials were prepared using a facile one-pot method by reducing Ni²⁺ with hydrazine hydrate in aqueous solution of sodium dodecyl sulfate（SDS） and polyvinylpyrrolidone（PVP） at 65 ℃. The surface morphology and internal structure of the nickel nanomaterials were characterized. The results showed that the nickel nanomaterials were hollow submicrospheres with a large number of mesopores in the thicker shell layer， and the surface of the submicrospheres distributed with pine-needle-like superimposed morphology. The overall morphology of the hollow nickel submicrospheres with hierarchical nano-structure were like closed bird’s nest. The selective hydrogenation reaction of phenol was catalyzed by the hollow nickel submicrospheres at 150 ℃ for 4 h. The phenol conversion and cyclohexanol selectivity were up to 100% and 90%， respectively. In addition， the catalytic performance of the hollow nickel submicrospheres nearly did not decrease and the surface of the catalyst was not oxidized after 20 cycles exposed in the air. Therefore， the hollow nickel submicrospheres with hierarchical nano-structure have excellent catalytic activity and excellent cycle stability， and have the potential as a good candidate catalyst for packed bed or fluidized bed.



Preparation of Lignin Nanocarbon and Its Performance as a Negative Electrode for Lithium-ion Batteries

YI Conghua, SU Huajian, QIAN Yong, LI Qiong, YANG Dongjie

2021, 42(6):  1807-1815.  doi:10.7503/cjcu20200904

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Enzymatically hydrolyzed lignin extracted from residues in the biorefinery industry was hydrothermally combined with zinc acetate under alkaline conditions to prepare a low molecular weight lignin/zinc oxide compound（LWL/ZnO）， which was then carbonized and etched to obtain Lignin nano-carbon material（NLC）. After characterizing its morphology and structure， it is found that NLC has a nano-particle structure with a particle size of less than 50 nm， with a specific surface area of 833.25 m²/g， and a mesoporosity as high as 58.07%. The mesopores with a pore diameter of 10 nm are the most abundant. The electrochemical performance test results show that NLC as a lithium-ion battery anode material has good cycle performance and rate performance， and its reversible specific capacity can maintain 705 mA·h/g after 200 cycles at a current density of 200 mA/g.



Construction and Zn Storage Performance of Three Dimensional Porous MnO_x@In₂O₃ Cubes

FAN Xiaoyong, WU Yan, SUN Ruibo, GOU Lei, LI Donglin

2021, 42(6):  1816-1825.  doi:10.7503/cjcu20200896

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Mn-based oxides have been widely researched as the cathode of Zn-ion batteries due to their high capacity and low-cost. However， their phase transformation， dissolution of Mn and unstable electrode/electrolyte interphase during cycling cause poor cycle lifespan， especially poor lifespan at low current densities and high discharge depth. In this work， three-dimensional（3D） porous MnO_x cubes were prepared and then a In₂O₃ layer was coated on their surface to gain 3D porous MnO_x@In₂O₃ cubes. The rich pores with size about 10 nm are beneficial to the rapid transport of H⁺ and Zn²⁺， In₂O₃ coating layer is beneficial to suppressing the dissolution of Mn and phase transformation of MnO_x electrodes and stabilize the electrode/electrolyte interphase during cycling. The 3D porous MnO_x@In₂O₃ electrodes deliver high capacity of 260 mA·h/g after 400 stable cycles at a small current density of 0.3 A/g， which is much better than most of reports. Besides， it also delivers high capacity of 81 mA·h/g after 4000 stable cycles at 1.8 A/g， high capacity of 73.4 mA·h/g even at high current density of 6.0 A/g. The Galvanostatic intermittent titration technique（GITT） and CV results reveal 3D porous MnO_x@In₂O₃ electrode has lower electrochemical polarization and large diffusion coefficient than those of 3D porous MnO_x electrode. The electrochemical impedance spectra results demonstrate 3D porous MnO_x@In₂O₃ electrode has more stable electrode/electrolyte interphase than that of 3D porous MnO_x electrode. The SEM images of 3D porous MnO_x@In₂O₃ electrode suffered 2000 cycles show a little In₂O₃ still dispersing on the MnO_x surface， which ensures the structure stability and stable cyclability.



One-step Synthesis of Amorphous Silica Aluminum Support Materials with Controllable Acidity and Porosity and Catalytic Performance of Their Pd-based Catalysts

WANG Yuxiang, YU Shen, LIU Zhan, LYU Jiamin, LI Xiaoyun, CHEN Lihua, SU Baolian

2021, 42(6):  1826-1836.  doi:10.7503/cjcu20200888

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The catalytic performance of porous material-supported catalysts depends significantly on the acidity and porosity of support materials. One of the most critical challenges in the field of support-based catalysts is to effectively control the acidity and porosity of support materials simultaneously. Herein， we synthesized a series of porous amorphous silica aluminum（ASA） support materials by a spontaneous self-assembly process in different solvents. Further， porous ASA supported Pd catalysts were prepared by an impregnation method. Particularly， the effects of the polarity of solvent and the initial Si/Al ratio of ASA on the support materials as well as the obtained catalyst were investigated thoroughly. Results show that synthesis in a solvent with lower polarity produces ASA materials possessing abundant mesopores. And by means of tuning initial Si/Al ratio， the acidity， BET surface area， and pore size of ASA materials can be controlled readily. The optimal synthesis condition achieves a BET surface area and total acid amount up to 349.6 m²/g and 1.389 mmol/g， respectively. Due to the high BET surface area and abundant mesopores， the as-prepared ASA-supported Pd catalyst exhibits high dispersion of Pd metal particles， the dispersion of Pd is up to 63.17%. As a result， the obtained catalyst outperforms excessively its counterpart supported on commercial Al₂O₃， achieving a conversion of 99.75% and a selectivity to phenylamine of 94.62% for the hydrogenation of nitrobenzene and a conversion of 40.61% and a selectivity to benzaldehyde of 38.09% for the oxidation of benzyl alcohol. This facile and effective synthesis method makes it possible to synthesize efficient catalysts according to desired catalytic reactions.



Photo-thermal Coupling Water Splitting over Fe-doped TiO₂ with Various Nanostructures

WU Qiliang, MEI Jinghao, LI Zheng, FAN Haidong, ZHANG Yanwei

2021, 42(6):  1837-1845.  doi:10.7503/cjcu20200886

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Oxygen vacancy（V_O） is an important part of the defect engineering. The direct thermal application of reductive photo-induced V_O has been regarded as an effective way for solar utilization in the field of hydrogen production from pure water splitting. Based on TiO₂ nanomaterials synthesized by various preparation me-thods， the performance of pure water splitting in photo-thermal coupling was tested on a variety of topography TiO₂ samples and its promoted form with Fe ions doping. The high resolution transmission electron microscopy（HRTEM）， X-ray diffraction（XRD） and electron paramagnetic resonance（EPR） were utilized for the observation of crystal characteristics. The diffuse reflectance spectroscopy（DRS）， photoluminescence（PL） and electrochemical characterization were applied to compare the materials properties. Moreover， the whole water splitting reaction pathway was performed via density functional theory（DFT）. Compared with hydrothermal nanosheets and nanowires， the nanoparticles prepared by sol-gel own abundant defects， resulting in a decline in hydrogen yield. To increase the photo-induced V_O generation during the photo reaction， which takes the highest energy barriers， the Fe doping was introduced into the nanomaterials， with the advantages of extended photoresponse， enhanced electron-hole pairs separation， prolonged carriers lifetime and decreased impe-dance. Meanwhile， defects in nanomaterials promote effective doping of Fe atoms， the average hydrogen yield on Fe-doped TiO₂ nanoparticles is 9.73 μmol/g in photo-thermal coupling reaction， which is almost 13 times to the bare TiO₂. The comparison and modification of nano TiO₂ with various morphologies provide a new approach for the solar functional materials.



Effect of CuAl₂O₄ Spinel Structure on CO Hydrogenation in Slurry Reactor

YAN Pengquan, WANG Jingrong, SHEN Yaxing, ZUO Zhijun, GAO Zhihua, HUANG Wei

2021, 42(6):  1846-1854.  doi:10.7503/cjcu20200883

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The CuAl₂O₄ spinels were prepared by the solid-phase method， co-precipitation method， citric acid method， and sol-gel method. The activity of CO hydrogenation over CuAl₂O₄ spinel was evaluated in the slurry reactor. And the structure of CuAl₂O₄ spinel was characterized by XRD， BET， SEM， TEM， NH₃-TPD-MS， H₂-TPR and XPS. The results showed that CuAl₂O₄ spinel prepared by different methods had various texture parameters， surface enrichment degree， decomposition and reduction ability， which further affected the catalytic performance. The CuAl₂O₄ spinel prepared by the solid-phase method showed a larger pore size and pore volume， and the highest CuAl₂O₄ surface enrichment degree， resulting in incomplete decomposition of the spinel. However， CuO produce by the spinel decomposition was totally redyced， and the ratio of Cu⁺/Cu⁰ was relatively high， which favored the formation of higher alcohols. The selectivity of C₂₊OH in the product was as high as 31.1%. The other three spinels with relatively low CuAl₂O₄ surface enrichment were completely decomposed， but part of the CuO was not reduced. Moreover， the proportion of Cu⁰ was obviously increased. The synergistic effect of Cu⁰ and γ-Al₂O₃ was beneficial to the production of dimethyl ether（DME）. The highest DME selectivity was up to 72.9%.



Vibrational Density of States Analysis of Proton Hydration Structure

ZENG Yonghui, YAN Tianying

2021, 42(6):  1855-1862.  doi:10.7503/cjcu20200866

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Proton transfer（PT） is a very important basic reaction process in chemical reactions. It is important for understanding the dynamic process of biology and the development of proton fuel cells. In the work， the hydration structure of proton and the dynamic response of the hydration structure involved in the PT process in aqueous solution were studied in detail by the molecular dynamics simulation using multistate empirical valence bond（MS-EVB） model. Based on the theoretical framework of MS-EVB model， the proton hydration structure mainly exists in the form of H₉O₄⁺（Eigen） or the intermediate of H₅O₂⁺（Zundel）， and the Eigen is do-minant in these two structures. Density of state（DOS） spectra of different hydration structures in PT process show continuous broad absorption band in the range of 2000―3000 cm^-1， which is mainly attributed to the Eigen contribution because there are no obvious characteristic peaks for a Zundel structure at the above frequency. The characteristic peak is closely related to the strong hydrogen bonding in the first hydration shell of hydronium ions in Eigen structure. Moreover， for Zundel structure， a relatively obvious shoulder appears at 1760 cm^-1， which is attributed to the characteristic of PT mode， in agreement with previous study. Through the analysis of DOS spectrum associated with PT， we hope to improve the understanding on the continuous broad absorption band in the infrared spectrum of the dilute acid solution， and the microscopic dynamical characte-ristic of PT in the aqueous solution.



Enhancement Effect of Low-power Ultrasound on Iopamidol Chlorination and the Degradation Pathway

WEI Hong, YANG Xiaoyu, LI Kebin, HAO Miao, FU Ran

2021, 42(6):  1863-1870.  doi:10.7503/cjcu20200852

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Iopamidol（IPM）， as a widely used iodinated X-ray contrast media， was degraded by an ultrasound-enhanced chlorination process. Effects of the parameters， such as NaClO concentration， ultrasonic power， and reaction temperate on IPM degradation were investigated. The main reactive radicals and their respective contribution in IPM degradation were identified and estimated. Meanwhile the intermediates were analyzed by high performance liquid chromatography-tandem mass spectrometry（HPLC/MS/MS） as well. The results showed that IPM degradation was significantly enhanced by ultrasonic excitation of NaClO. NaClO oxidation， hydroxyl radical and reactive chlorine species were involved in IPM degradation， and their contribution for degrading 10 mg/L of IPM in the presence of 0.12 mmol/L of NaClO at pH=5.8 under 25 ℃ were 15.82%， 4.65% and 79.53%， respectively. When NaClO concentration was in the range of 0―0.24 mmol/L， an increase in NaClO concentration resulted in IPM degradation efficiency going up from 4.75% to 91.12% in 60 min. Nevertheless， the ultrasound power displayed an optimum value of 28.5 W. The degradation of IPM under the US/NaClO system within 15―45 ℃ were fitted with the first-order kinetics and the corresponding activation energy（E_a） was calculated to be 59.03 kJ/mol. Finally， five intermediates were identified by HPLC/MS/MS analysis， together with the theoretical calculation of Density functional theory（DFT）， the degradation pathway of IPM in the US/NaClO system was proposed.



Combustion Mechanism Construction Based on Minimized Reaction Network： C1⁃Oxygen Combustion

LI Yiwei, SHENTU Jiangtao, WANG Jingbo, LI Xiangyuan

2021, 42(6):  1871-1880.  doi:10.7503/cjcu20200846

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With the development of the combustion mechanism， the reaction networks become more and more detailed， resulting in a larger mechanism size. The too large size of the reaction mechanism will make the combustion numerical simulation difficult in practice. In this work， the minimal reaction network （MRN） method proposed in previous work is used to develop the C1 combustion reaction mechanism with the minimum number of reaction steps and specified number of species. In the C1 combustion process， 14 independent reactions were determined for a system of 17 species， including 8 species and 6 independent reactions of hydrogen combustion. However， some global reactions need to be replaced by other elementary reaction steps owing to the lack of the rate constants. In this way， a 25-step detailed mechanism of C1 combustion（MRN-C1） was constructed. The reliability of MRN-C1 mechanism was verified by ignition delay time and laminar flame speed. When applying the multi-fuel mechanism to a single fuel， e.g. CH₄， there exists a few suspended species that have no other consumption path after they are produced. Therefore， mechanism-extracting of MRN-C1 aimed at the single fuel combustion was performed. Such a treatment can further reduce the size of the mechanism for a specified fuel， it saves the cost in large-scale-computation of combustion.



Cobalt Substitutions in Lanthanum Manganate Photocatalyst： First-principles and Visible-light Photocatalytic Ability Investigation

LI Yishan, GUO Liang, PENG Sifan, ZHANG Qingmao, ZHANG Yuhao, XU Shiqi

2021, 42(6):  1881-1890.  doi:10.7503/cjcu20200831

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Perovskite photocatalyst has attracted many attention due to its good stability and perfect catalytic decontamination ability. Sol-gel method can effectively and stably synthetize LaMnO₃. Perovskite can effectively adjust the bandgap with substitute B site of metal and improve its catalytic performance. In this paper， The electronic and optical properties of LaMnO₃ and the combination of LaMn_1-xCo_xO₃ were simulated by the first principle method. The results showed that Co substitutions can improve the absorption ability to visible light of LaMnO₃. LaMnO₃ was synthetized by sol-gel method， and the stability of the structure under different pH environment was explored. The results showed that LaMnO₃ was more stable under neutral or alkaline environment. The effect of LaMnO₃ in different Co substitution concentration on the photocatalytic activity was studied. Among that， the results of experiment prove that the Co substitutions in LaMnO₃ can improve the photocatalysis ability of LaMnO₃. Compare with other proportion of Co substitutions， LaMn_0.9Co_0.1O₃ powder showed the highest photocatalytic activity， and the degradation rate of methyl orange under visible light was 54%， which is 17% higher than that of LaMnO₃.



Electrodeposition Mechanism and Surface-enhanced Raman Spectroscopic Effect of Nano-sized Silver Layer

CHEN Feng, CHENG Na, ZHAO Jianwei, SONG Yitian, SUN Yanyan, LOU Xinli, TONG Xiayan

2021, 42(6):  1891-1898.  doi:10.7503/cjcu20200827

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The electrodeposition mechanism of nano-sized silver layer with large area uniformity and smoothness was studied， the corresponding preparation process was optimized， and its application in surface- enhanced Raman spectroscopy（SERS） was explored. The result shows that the nucleation mechanism of electrodeposition transitions gradually from progressive one to instantaneous one with negative shift of electrode potential and the best effect of SERS was achieved under such conditions， current density is 1.0 A/dm²， area ratio of cathode to anode is 1∶10， electrodeposition temperature is 20—30 ℃. Under ideal conditions， the silver grains are oriented along the （111） plane， with the diameters mainly distributing between 6—11 nm from scanning electron microscopy. The prepared coating can be used as SERS active substrate with high sensitivity and low limit of detection（LOD）， the LOD of R6G was determined to below 1.0×10^-12 mol/L， the coating also can realize uniform Raman enhancement effect on a large scale at the same time， which shows great potential for alpplication.



Reaction Mechanism for Rh（Ⅱ）-catalyzed ［3+3］ Cyclization of Indole Derivatives and Propertis of Product

TIAN Shengqiao, WEI Meiju

2021, 42(6):  1899-1907.  doi:10.7503/cjcu20200803

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The density functional theory was used to study the ［3+3］ internal cyclization of 3-diazoindolin-2-imide and 2H-azirine catalyzed by dirhodium. The reaction mainly involved the formation of rhodium metal carbene， activation cleavage of C―N bond， and indole ［3+3］ internal cyclization. The calculation results showed that the rhodium catalyst showed coupling effects to promote C-N coupling and 2H-azirine C―N bond cleavage. The reaction rate-controlled step was occurred during the indole ［3+3］ cyclization. The rhodium catalyst was released before the ［3+3］ cyclization. One product had a lower hole recombination energy and a large Stokes shift in the absorption and fluorescence emission spectra， which showed that it could be good hole transport material and fluorescent emission material.



Surface Modification and Work Function Control of Carbon Film Electrode Based on Electrochemical Diazonium Reduction

XU Xiaona, SHI Chengqian, DING Xiaohai, XUE Junhong, WANG Dong, TIAN Lixian, LI Baili, ZHU Yanying, YU Xi

2021, 42(6):  1908-1913.  doi:10.7503/cjcu20200795

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Pyrolyzed photoresist films（PPF） is a new type of carbon-based electrode material of excellent and modulable performance. To facilitate its applications in organic electronic devices， we modulated the work function（?） of the PPF via the electrochemical diazonium reduction method to grow mixed layer containing two components， trifluoromethyl（CF₃-PD） and p-anisidine（OCH₃-PD） on the surface of the PPF electrode. By adjusting the relative concentration of the two-components in the solution， gradient work functions of the PPF electrode were obtained. Work functions of the modified PPF electrodes were characterized by means of UV photoelectron spectroscopy（UPS） and Kelvin probe microscope（KPFM）. The results show that as the concentration of the CF₃-PD component in the mixed solution increases from 0 to 100%， the work function of the PPF electrode（?=4.75 eV） increases gradually from 4.5 eV to 5.14 eV. Our work has realized the tunable work functions of PPF electrodes and provided possibility for the further applications of PPF electrodes for molecular optoelectronic devices.



Molybdenum Peroxide Anchored on Fluoronated UiO-66 as Catalyst in the Oxidation of Sulfur Containing Compounds

ZHANG Renli, WANG Yao, YU Zhiquan, SUN Zhichao, WANG Anjie, LIU Yingya

2021, 42(6):  1914-1923.  doi:10.7503/cjcu20200789

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The oxidative desulfurization（ODS） process is a very important tool to reduce sulfur emission and to comply with the increasingly stringent environmental regulations for fuels. Metal-organic frameworks with high specific surface area can introduce the 2nd metal sites via. chemical bonding， thus constructing a heterogeneous catalytic system with good chemical stability， which has advantages in the field of liquid-phase oxidative desulfurization. In this work， the ligand functional groups of UiO-66 were modified by pre-modification. Firstly， the hydrophilic and hydrophobic properties of UiO-66 were regulated by introducing —F； secondly， MoO（O₂）₂ was loaded on the UiO-66 framework by introducing —NH₂. The contact angle test showed that the introduction of fluorine effectively improved the hydrophobicity of the carrier surface， and thermogravimetric analysis proved that there were more ligand missing on the fluorine-modified UiO-66 framework， thus effectively improving the Lewis acidity of the overall MOF framework. The effects of reaction temperature， ratio of oxygen to sulfur and catalyst dosage on catalytic performance were investigated by orthogonal experiment with dibenzothiophene（DBT） oxidation as the model reaction and cumene hydroperoxide（CHP） as the oxidant. The results show showed that O/S molar ratio is the key factor affecting DBT conversion. The catalytic activity of the fluorine modified catalyst has no obvious change after five catalytic cycles， and the framework remains stable.



Preparation of Cellular C₃N₄/CoSe₂/GA Composite Photocatalyst and Its CO₂ Reduction Activity

WANG Peng, YANG Min, TANG Sengpei, CHEN Feitai, LI Youji

2021, 42(6):  1924-1932.  doi:10.7503/cjcu20200745

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C₃N₄/CoSe₂ nanoparticles were synthesized by hydrothermal method using cobalt chloride hexahydrate， selenium powder and urea as precursors， and then were anchor on the surface of graphene aerogel（GA） to prepare C₃N₄/CoSe₂/GA photocatalyst. The structure， surface morphology and optical properties of the materials were characterized by X-ray diffraction（XRD）， X-ray photoelectron spectroscopy（XPS）， scanning electron microscopy（SEM）， transmission electron microscopy（TEM） and UV-Vis diffuse-relective spectroscopy（UV-Vis DRS）. At the same time， the photocatalytic activity of the prepared nanomaterials was investigated by reduction of CO₂ to CO with using the xenon lamp as visible light source. The results showed that the cellular C₃N₄/CoSe₂/GA catalyst was successfully prepared by introducing CoSe₂ and GA on the surface of C₃N₄ nanometer sheet， and the coupling of GA and CoSe₂ with C₃N₄ could significantly improve the optical absorption density and expand the optical response range， showing lower fluorescence intensity and maximum electron transfer rate. Under the same photocatalysis condition， C₃N₄/CoSe₂/GA displayed the highest catalytic efficiency for CO₂ reduction， the CO yield reached 5.75 μmol·g^-1·h^-1， and the photocatalytic performance was good in repeating process.



Effect of Light Source on the Photocatalytic Performance of Dihydroxynaphthalene by Water-soluble Sulfonated Porphyrins

ZHU Qichen, XIONG Ming, TAO Siyu, TANG Siwei, REN Qizhi

2021, 42(6):  1933-1941.  doi:10.7503/cjcu20200727

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Water-soluble sulfonated porphyrins（TPPS， TMPPS and FeTPPS） were synthesized. Taking hydrogen peroxide as the oxidant and iodine-tungsten lamp as the light source， these porphyrins can photo-catalyze the oxidation of 1，5-dihydroxynaphthalene efficiently， the product is 5-hydroxy-1，4-naphthalene-diquinone. The fluorescence quantum yield and lifetime were measured， and the catalytic mechanism was analyzed. The effect of light sources under different wavelength range（350―650 nm） and power range（0―20 W） on the photo-catalytic activities by different porphyrins were investigated. It is shown that light sources with different wave bands have a certain effect on the photocatalytic performance of porphyrin catalysts. The order of the reactant conversion rate is： λ_380―385>λ_360―370>λ_580―585>λ_620―630>λ_492―577>λ_450―470， which has close correlation with the ultraviolet-visible absorption of porphyrins. For free base porphyrins， when the same wavelength band of the light source was used， the reaction rate constants show fine linear relation with the power of the light source. For iron porphyrin FeTPPS， because of its photolysis， its catalytic activities are greatly depending on the catalyst stabilities at different power of the light sources.



Photochemical Fabrication and Performance of Polyaniline Nanowire/SnO₂ Composite Photocatalyst

YANG Sixian, ZHONG Wenyu, LI Chaoxian, SU Qiuyao, XU Bingjia, HE Guping, SUN Fengqiang

2021, 42(6):  1942-1951.  doi:10.7503/cjcu20200573

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A study on SnO₂/polymer composite photocatalytic materials was carried out. The polyaniline（PANI） nanowires with determined morphology were employed as composite units to control the formation and recombination of SnO₂ by a room temperature photochemical method to achieve PANI enhanced photocatalytic activity. PANI nanowires were directly dispersed in a mixed solution of SnSO₄ and H₂SO₄ to obtain PANI nanowire/SnO₂ nanoparticle composites by UV irradiation. The morphology and composition of the composites were analyzed， and it was found that the two components were interwoven and some particles grew directly on the nanowires. The photocatalytic activity of the composite under low power UV lamp was studied with rhodamine B solution as the target degradation pollutant. The results showed that PANI nanowires could obviously enhance the photocatalytic activity of the SnO₂， and the enhancement effect changed regularly with the growth time of SnO₂. The photocatalytic activity of the composite obtained in the optimal recombination time was nearly 3 times that of the pure SnO₂. By measuring and analyzing on the energy level structure and the photocataly-tic reaction process， it is considered that the formation of z-scheme heterojunction promotes the separation of photogenerated electrons-holes， and then enhances the photocatalytic activity of the material. The subsequent photochemical recombination SnO₂ with polymer nanomaterials with regular morphology as components is a new recombination mode. It has the characteristics of green， easy to operate and cheap， easy to regulate SnO₂ photocatalytic activity， and can promote SnO₂ application in the field of photocatalysis.



Polymer Chemistry

Preparation and Property of A Novel Hemoperfusion Adsorbent For Protein-bound Uremic Toxins

LIU Yunhong, PENG Xinyan

2021, 42(6):  1952-1964.  doi:10.7503/cjcu20200879

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Protein-bound uremic toxins（PBUTs）， as important risk factors for the progression of chronic kidney disease（CKD）， can’t be cleared efficiently by traditional hemodialysis method until now. Therefore， it still remains a challenge for developing hemoperfusion adsorbents with enhanced PBUTs removal efficiency. In this work， a facile， one-step method was developed for the synthesis of imidazole-based hypercrosslinked polystyrene porous adsorbent， HCP（St-DVB-VMZ）， using imidazole modified low crosslinked polystyrene microspheres， P（St-DVB-VMZ）， as precursor， followed by Friedel crafts alkylation reaction with small-molecule external cross-linking agent. The chemical structure and micro-pore structure of the adsorbent were characte-rized by Fourier transform infrared spectroscopy（FTIR）， X-ray photoelectron spectroscopy（XPS）， scanning electron microscopy（SEM） and N₂ adsorption-desorption analysis. The results demonstrated that HCP（St-DVB-VMZ） had abundant microporous structure， and the specific surface area was up to 709 m²/g. Adsorption experiments showed that the as-fabricated HCP（St-DVB-VMZ） exibited good removal capacity for both the PBUTs（IS， PCS and IAA） and the middle molecular toxins（PTH，β2M and IL-6）. The hemocompatibility assays indicated that the HCP（St-DVB-VMZ） possessed good in vitro hemocompatibility，making it suitable for contacting with blood as a hemoperfusion absorbent for clinical application.



Preparation of Terpolymer Microspheres with Broad Band UV-blocking Performance

LIU Xiaojin, LI Ting, WANG Yang, DONG Weifu

2021, 42(6):  1965-1977.  doi:10.7503/cjcu20200850

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Monodispersed ternary polymer microspheres with broadband UV-blocking performance were successfully prepared through the self-stabilized precipitation polymerization（2SP） of vinyl acetate（VA）， maleic anhydride（MA） and a commercial vinyl UV absorber， 2-｛2-Hydroxy-5-［2-（methacryloyloxy）ethyl］phenyl｝-2H-benzotriazole（NB）， using 2，2'-azobisisob-utyronitrile（AIBN） as an initiator. The effects of solvent， monomer feed ratio， initiator concentration， monomer concentration， reaction temperature and reaction time on the morphology， particle diameters， size distribution and UV-blocking performance of the resultant polymeric microspheres were investigated systematically. The structure， appearance and UV-blocking property were studied by Fourier transform infrared（FTIR） spectroscopy， scanning electron microscopy（SEM）， laser diffraction particle size analyser and UV transmittance spectroscopy. The experimental results indicated that the mixed solvent of ethyl benzoate and n-heptane with 7∶3 volume ratio is the optimal solvent for preparation of monodispersed poly（VA-co-MA-co-NB）（PVMN） microspheres via 2SP process. The diameters and UV-blocking performance of the polymeric microspheres can be easily controlled by facile change of reaction conditions. With the increase of ratio of UV absorber NB， initiator concentration， monomer concentration and reaction temperature， the size of the polymeric microspheres increased while still keeping well dispersity. The dry diameter of PVMN microspheres can be ranged from （249±19） nm to （1434±213） nm， and optical PVMN microspheres could surprisingly block about 90% UV radiation. In addition， the established preparative strategy can be potentially extended to other UV-absorbant vinylic monomer and is a versatile method for fabricating stable polymer UV absorber.



Synthesis and Properties of Polyimide Resin Containing Acetylene and Benzoxazine Double Crosslinking Moieties

WU Tao, FANG Yuting, DONG Jie, ZHAO Xin, ZHANG Qinghua

2021, 42(6):  1978-1986.  doi:10.7503/cjcu20200829

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To develop high-performance polyimide resins that can be cross-linked at a relative low temperature， a novel polyimide resin（PIBzA） was designed and synthesized by introducing the benzoxazine ring into the acetylene-terminated polyimide oligomer. During the curing process， a ring-opening polymerization of benzoxazine and cross-linking of acetylene take place in the oligomer， and a novel double cross-linked network can be formed in the cured resin. Interestingly， an approximately 32 ℃ lower in curing temperature can be observed for this polyimide resin compared with the sample without the benzoxazine moiety. Meanwhile， the introduction of benzoxazine moiety does not destroy the excellent thermal resistance of polyimide resin， and the glass transition temperature（T_g） of the cured PIBzA resin ranges from 266 to 290 ℃， and the 5% mass loss temperature is close to 500 ℃. Meanwhile， the cured PIBzA resin shows relative low dielectric constants of 2.3―3.0 and low dielectric loss of 0.002―0.008， which can meet the requirements of wave-transparent composites and advanced microelectronic packaging materials.



Construction of Room Temperature Phosphorescence System of Thioflavin-based Polylactide/Benzenesulfonic Acid

LI Xinyu, LI Zhiwei, ZHANG Xingyuan

2021, 42(6):  1987-1993.  doi:10.7503/cjcu20200770

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The electron?donating groups， —OH， —SH and —MeOH， were respectively introduced on thioflavin， and three thioflavin derivatives， 2?［4?（benzothiazole?2?yl） phenoxy ethan?1?ol］（BT?OH）， 2?｛［4?（benzothiazole?2?yl）phenyl］thio｝ ethan?1?ol（BT?SH） and 2?［4?（benzothiazole?2?yl）?2?methoxyphenoxy］ ethan?1?ol（BT?M?OH）， were synthesized. The derivatives were used as initiators for the polymerization of D，L?lactide to obtain three thioflavin?based polylactides. Benzenesulfonic acid was subsequently added to construct thioflavin?based polylactide/benzenesulfonic acid system that can produce room temperature phosphorescence. The tunable molecular emission from fluorescence to phosphorescence was realized， and the longest life of phosphorescence is 108.19 ms. The results reveal that the introduction of benzenesulfonic acid can cause the thioflavin?based polylactide to produce an intramolecular charge?transfer state， and the protonation effect leads to green and orange phosphorescent emission.



Preparation and Properties of Polyaryletherketones-based Electromagnetic Wave Absorption Composite Material

FANG Jiyong, JIANG Zhenhua, YUE Xigui

2021, 42(6):  1994-2001.  doi:10.7503/cjcu20200762

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Magnetic porous carbon composite absorber（WPC/MNPs-80） developed in our previous work was specially selected to synthesize polyaryletherketones（PAEK） based electromagnetic wave absorption material（6F-PAEK-Crosslink@WPC/MNPs-80） through a solution blend method. In order to improve the solubility of the polymer matrix and solve the deposition problem of the absorber particles during the membrane-forming process， PAEK with hexafluoroisopropyl and amino groups（6F-PAEK-NH₂） was designed and synthesized. According to the results， the crosslinked structure of the matrix can not only solve the deposition problem but also bring the composite material with excellent properties， such as thermal property and mechanical property. 6F-PAEK-Crosslink@WPC/MNPs-80 shows fine electromagnetic（EM） absorbency. The minimum RL value of -33 dB is obtained with the bandwidth of 4.8 GHz at a membrane thickness of 1.4 mm， while a minimum Reflection loss（RL） value of -44.5 dB is obtained with the bandwidth of 3.1 GHz at a membrane thickness of 1.8 mm. Therefore， 6F-PAEK-Crosslink@WPC/MNPs-80 is a promising candidate for electromagnetic wave attenuation because of its excellent comprehensive properties.



Preparation and Characterizations of Cross-linked Sulfonated Poly（ether ether ketone）/Partially Fluorinated Sulfonated Poly（aryl ether sulfone） Blend Membranes

PU Yangyang, NING Cong, LU Yao, LIU Lili, LI Na, HU Zhaoxia, CHEN Shouwen

2021, 42(6):  2002-2007.  doi:10.7503/cjcu20200759

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A type of blend and cross-linked proton exchange membrane（CMB） based on sulfonated poly（ether ether ketone）（SPEEK）/partially fluorinated sulfonated poly（aryl ether sulfone）（SPFAES） were prepared， and the properties including water uptake， swelling ratio， mechanical properties， thermal properties， proton conductivity， chemical stability and fuel cell performances of the CMBs were evaluated. The cross- linking structure was constructed in the blend system by adding dehydrating agent during solution casting. The results indicate that the CMB membranes all exhibit excellent mechanical strength in dry state and greatly improved physicochemcial stability due to the good compatibility and dispersion between SPEEK and SPFAES， and the rearrangement and cross-linking of polymer chains. With low ion exchange capacity（1.21—1.51 mmol/g）， the proton conductivities of CMB membranes reach 122—219 mS/cm（80 ℃）， and the maximum power density of the CMB4 membrane achieves 530.5 mW/cm²（80 ℃） in a single hydrogen-oxygen fuel cell.



Effects of Co-reagent for Improving the Performance of Polyamide Composite Reverse Osmosis Membrane

YAN Tingting, ZHANG Na, LI Qiang, LI Zhenhua, LI Chunhui, LI Xue, YU Ru, WANG Rui, WANG Jihua, CAO Zanxia

2021, 42(6):  2008-2014.  doi:10.7503/cjcu20200746

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In a bid to improve the performance of polyamide composite reverse osmosis membranes（PA-RO-x， x represents DMAc concentration）， N，N′-dimethylacetamide（DMAc） was applied as co-reagent added into the aqueous m-phenylenediamine solution for interfacial polymerization reaction with trimesoyl cloride. Characterization of the PA-RO-x membranes by X-ray photoelectron spectroscopy（XPS） and attenuated total reflectance Fourier transform infrared（ATR-FTIR） spectroscopy confirmed that with the increase of DMAc concentration， the content of cross-linked amide linkages in PA-RO-x membranes increased relative to the li-ner pendant carboxylic acid groups. By the field emission scanning electron microscope（FE-SEM） and atomic force microscope（AFM）， it is obviously showed that the surface morphology gradually changed and the surface roughness of composite reverse osmosis membranes increased as the increase of DMAc content. The static water contact angle measurement with sessile drop method revealed that the hydrophilicity of the composite reverse osmosis membranes was enhanced after DMAc was added. According to the above mentioned charac-terization results， it was confirmed that DMAc play a key role that could effectively reduce the immiscibility between aqueous phase and oil phase， and help to improve the diffusion rate of m-phenylenediamine from aqueous phase to n-hexane for accelerating the reaction between m-phenylenediamine and trimesoyl cloride. At the same time， the increase of the linkages of cross-linked amide can be as hydrogen-bond sites， which can be beneficial for water molecules penetrate through the polyamide composite reverse osmosis membranes quickly without considerable losing the salt rejection. The higher the surface roughness of the membranes， the higher the permeate flux. The water permeate flux and NaCl rejection of PA-RO-5.2（DMAc concentration is 5.2%， mass fraction） reached 66.1 L/m²·h and 98.7%， respectively， for 2 g/L NaCl under 1.6 MPa. Compared with the polyamide reverse osmosis composite membrane without DMAc addition， the permeate flux of PA-RO-5.2 increased by 115% and the desalination rate decreased by 0.9%.



Preparation and Dielectric Properties of Nanocomposites with Double Cross-linking Network Structure

DING Jiale, JIN Lan, CUI Zengduo, ZHANG Haibo, ZHANG Yunhe, JIANG Zhenhua

2021, 42(6):  2015-2023.  doi:10.7503/cjcu20200740

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A kind of BaTiO₃/poly（aryl ether ketone） nanocomposite（BT-BCB/c-DPAEK） with double cross-linking network was obtained by controlling the reaction temperature and time according to the difference of activation energy of functional groups. It was found that BT-BCB/c-DPAEK composite film had better mechanical and thermal properties than pure polymer film and the composite films without crosslinking treatment or with single crosslinking treatment. At the same time， due to the improvement of the interface between the two phases of the composite and the limitation of the polymer molecular chain movement at high temperature， BT-BCB/c-DPAEK showed excellent energy storage performance. Especially at 150 ℃ and 300 MV/m， it still maintained an discharge energy density of 1.75 J/cm³ and a discharge efficiency as high as 80%.



Facile Synthesis and Properties of Robust and Anti-swelling Hydrogels

LUO Chunhui, ZHAO Yufei

2021, 42(6):  2024-2033.  doi:10.7503/cjcu20200722

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Robust and anti-swelling hydrogels based on commercial available polyvinyl alcohol（PVA） and chitosan（CS） were prepared via freezing-thawing cycle to prepare the precursor PVA-CS hydrogel firstly， followed by soaking in sodium chloride aqueous solution and dialysis against water to obtain the resultant PVA-CS-6.16-30 hydrogel. The microstructures of the two hydrogels were characterized， and their mechanical pro-perties were evaluated. Due to the multiple interactions of hydrogen bonding， crystalline region and chain entanglement， the obtained PVA-CS-6.16-30 hydrogel dissipated external energy more effectively. Compared with the precursor PVA-CS hydrogel， the free water content and mesh size of the resultant hydrogel declined from 62.8% and 6.11 to 52.6% and 5.21 nm， respectively. In contrast， the gel fraction， cross-linking density and crystalline degree of PVA increased from 58.6%， 7.69×10^-4 and 14.8% to 86.8%， 9.97×10^-4 mol/cm³ and 17.2%， respectively. Benefited from the higher cross-linking density and more homogeneous gel framework， the tensile strength， elongation at break， toughness as well as compressive stress of the resultant hydrogel increased to 2.9 MPa， 229%， 3.3 MJ/m³ and 7.6 MPa， respectively. Furthermore， it exhibited excellent anti-swelling and creep-resistant abilities. The resultant hydrogel maintained its original shapes and mechanical properties（tensile and compressive strength were 2.8 and 7.5 MPa， respectively） even after soaking in PBS aqueous solution for 7 d at 37 ℃. We hope that the full-fledged starting material， easy-operated process and balanced properties of the resultant hydrogel will promote the development of tissue engineering and biomedical materials for commercial applications.



Nonlinear Rheological Behavior of Long Chain Branching Polypropylene

DU Bin, CHEN Shangtao, ZHANG Fengbo, SHI Xingbo, LI Rongbo

2021, 42(6):  2034-2040.  doi:10.7503/cjcu20200717

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The nonlinear rheological behavior of long chain branching polypropylene was investigated syste-matically with large amplitude oscillatory shear test. The results suggested that the scaling low between the relative amplitude I_3/1 and the strain obtained by the Fourier transform can clearly illustrate the difference between the linear and the long chain branching polypropylene， and then the nonlinear coefficient was defined to measure the level of long chain branching. Additionally， the relationship between I_3/1 and strain under high strain can further describe the characteristics of long chain branching structure in nonlinear flow field， and thus the relationship between the long chain branching structure and the nonlinear rheological response was obtained. Through the stress wave decomposition method for Lissajous plot， the difference of viscoelasticity between inter- and intra-cycle was found. The nonlinear viscoelastic response of long chain branched structure was weaker than that of linear structure under large amplitude oscillatory shear， and the higher the degree of branching， the weaker the nonlinear response.



High Temperature Resistant and Soluble Polyimide Resins and Their Composites

WANG Xianwei, KE Hongjun, YUAN Hang, LU Gewu, LI Liying, MENG Xiangsheng, SONG Shulin, WANG Zhen

2021, 42(6):  2041-2048.  doi:10.7503/cjcu20200689

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Two soluble imide oligomers and their composites were prepared， and their processability， the interfacial morphology， and thermal， dielectric and mechanical properties were systematically investigated. The results revealed that the oligomers possessed excellent processability， evidenced by their good solubility in aprotic solvents and low melt viscosities. The 5% mass loss temperatures of the cured resins were higher than 550 ℃. The temperature of glass transition（T_g） values of cured PI-1 and PI-2 were 430 and 380 ℃， respectively. The quartz fiber reinforced composites displayed relatively low dielectric constant and dielectric loss at a frequency of 1─3 GHz. Carbon fiber/PI-1 composite retained 62% of its original flexural strength and 48% of its original inter-laminar shear strength at 420 ℃， indicative of their excellent mechanical properties at eleva-ted temperatures. Composites with a thickness higher than 45 mm were fabricated through compress-molding， which further demonstrates the excellent processability of the resins.



High-temperature Proton Exchange Membranes Based on Cross-linked Polybenzimidazole/hyperbranched-polymer Blends

CAO Kaiyue, PENG JinWu, LI Hongbin, SHI Chengying, WANG Peng, LIU Baijun

2021, 42(6):  2049-2055.  doi:10.7503/cjcu20200656

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In this study， we introduced a hyperbranched poly（p-chloromethylstyrene）（H-VBC） into a soluble high-molecular weight arylether-type polybenzimidazole（OPBI） matrix， and a new type of cross-linking system（OPBI/H-VBC-1 and OPBI/H-VBC-2） based on polybenzimidazole/hyperbranched polymer was obtained through the convenient solution blending-membrane casting preparation process. Finally， the comprehensive performance of the blend membranes was greatly improved. In comparison to the pristine OPBI membrane， the cross-linked blend membranes had more excellent dimensional stability and resistance to plasticization. After soaking in 85% phosphoric acid for 72 h， the volume swelling ratios of OPBI/H-VBC-2 and OPBI/H-VBC-QA-2（the quaternized membrane） were only 184.2% and 152.4%， respectively； while the swelling ratio of OPBI reached 336.5%. The maximum tensile strengths of OPBI/H-VBC-2 and OPBI/H-VBC-QA-2 reached 36.3 and 21.9 MPa， respectively， which were 56%—233% higher than the 10.9 MPa of OPBI membrane. We also found that the quaternized membranes had a higher ratio of proton conductivity to phosphoric acid absorption level than corresponding unquaternized ones. At 200 ℃， the proton conductivities of the quaternized composite membrane reached 151.5 and 103.4 mS/cm， respectively. Further， a comparative study showed that the quaternized cross-linked blend membranes had a better balance ability of proton conductivity and mechanical strength than most of the reported high-temperature proton exchange membranes（HT-PEMs）.



Interactions Between Hydrophobic Associating Poly（sodium acrylate） and a Zwitterionic Surfactant in Non-aqueous Media and Low Temperature Environment

HAN Yixiu, WU Dianguo, LI Hongpu, YIN Hongyao, MEI Yongjun, FENG Yujun, ZHONG Zuqin

2021, 42(6):  2056-2064.  doi:10.7503/cjcu20200631

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Hydrophobic associating polymers and surfactants are the main materials used to fabricate viscoelastic fluids. The interaction between these polymers and surfactants exerts significant effect on the fluids properties， so it has been a popular research topic in this field. However， previous studies only focused on aqueous systems at room temperature or above， there was few researches related to the extremely low temperature environment. In this paper， the interactions between the neutralized salt of hydrophobically modified polyacrylate acid（HMPA） and zwitterionic surfactant erucyl dimethyl amidopropyl betaine（EDAB） in mixed ethylene glycol/water at 20 ℃ and -20 ℃ were studied， and the effects on the rheological properties were examined. The rheological behavior of HMPA in pure water and in the mixed ethylene glycol/water were first investigated， and the rheological response of HMPA-EDAB in ethylene glycol/water and their self-assembly morphology were then studied. It is found that the introduction of ethylene glycol in aqueous solution， on one hand， inhibits the association of hydrophobic chains on HMPA， resulting in the reduction on viscosifying ability. On the other hand， it also largely reduces the freezing point of the mixture. In the HMPA-EDAB system， the hydrophobic chains of HMPA go into EDAB micelles to form mixed micelles whose morphology is dependent on the concentrations of HMPA and EDAB as well as temperature， and thus affecting the fluid rheological properties. The sub-zero low temperature is beneficial for EDAB forming wormlike micelles， so that the synergistic effect between HMPA and EDAB becomes more obvious in this case.



Preparation of PVDF Hollow Fiber Membranes via Melt Spinning-stretching Method and Its Oil-water Separation Performance

GAO Yifei, XIAO Changfa, JI Dawei, HUANG Yangzheng

2021, 42(6):  2065-2071.  doi:10.7503/cjcu20200627

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Nowadays， green chemistry is attracting more and more attention. In this paper， polyvinylidene fluoride（PVDF） hollow fiber membranes were prepared by environment-friendly melt spinning-stretching method without any solvent and diluent involved in membrane preparation process. In particular， we selected perfluoroethylene propylene（FEP） as the dispersed phase and water-soluble polyethylene glycol（PEG） and calcium chloride（CaCl₂） as the pore-forming agents. The influences of stretching ratio on the structure and properties of PVDF hollow fiber membranes were studied in detail based on pore size distribution， mechanical properties and water-in-oil emulsion separation performance. The results show that the dispersed phase and pore-forming agents can be uniformly dispersed in the matrix phase， and the the pore size distributions are relatively narrow. With the increase of the stretching ratio， the mean pore sizes and porosities of the membranes also increase. Meanwhile， the hydrophobility of the membranes decreases， but the water contact angles are all above 100°. The M-3 membrane shows a good mechanical property and separation effect for water-in-oil emulsion， of which the tensile strength can be up to 19.3 MPa and the separation effects are all higher than 97% at 0.02 MPa after five cycles. The results demonstrate that the membrane is potentially applicable in oil-water separation process.



Materials Chemistry

Water-soluble Ag₂Te Quantum Dots with Emission in the Second Near-infrared Window

ZHOU Jieqiong, HUANG Yan, ZHANG Zhiling, PANG Daiwen, TIAN Zhiquan

2021, 42(6):  2072-2079.  doi:10.7503/cjcu20210034

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Quantum dots（QDs） have a wide range of applications in the field of biomedicine due to their unique optical properties. Ag₂Te， as a member of group Ⅰ-Ⅵ quantum dots， has the advantages of low biological toxicity and narrow band gap， which has attracted the attention of scholars at home and abroad. But currently there are few methods for synthesizing water-soluble Ag₂Te quantum dots， and the tunable fluorescence emission wavelength range is limited. This paper presented a new method of preparing water-soluble Ag₂Te quantum dots with fluorescence emission in the second near-infrared window（NIR-Ⅱ）. This method applied silver nitrate as the silver source and N-acetyl-L-cysteine as the ligand. Sodium tellurite was reduced with sodium borohydride to obtain the tellurium source. The reaction condition was mild， such as room temperature， atmospheric atmosphere， and no toxic organic compounds were involved. Moreover， through cationic treatment， the surface defects of Ag₂Te QDs were passivated and ultra-small water-soluble Ag₂Te quantum dots with uniform size could be obtained. The fluorescence emission was centered at 1160 nm with a quantum yield of 8.0%（using IR26 dye as reference）. The Ag₂Te quantum dots synthesized by this method had good biocompatibility， and obvious near-infrared fluorescence could be observed after QDs being injected into mice， showing potential for further biological applications.



Solvent-free and High-yielding Synthesis of Highly Efficient Red-emitting Carbon Dots and Their Application in White Light Devices

DING Hui, ZHOU Xuanxuan, ZHANG Zihui, XIA Kunlin, ZHAO Yunpeng

2021, 42(6):  2080-2084.  doi:10.7503/cjcu20200832

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Highly efficient red-emitting carbon dots（R-CDs） were synthesized on a large scale by a solvent-free method using o-phenylenediamine， 2，5-diaminobenzene sulfonic acid and aluminum trichloride as raw materials. The obtained R-CDs are approximately 2.4 nm in diameter， have a nitrogen content of 13%， and consist of a highly graphitized carbon core coated with abundant functional groups. Under light illumination with different wavelengths， the R-CDs in ethanol solution show an excitation-independent red emission at 704 nm， with a quantum yield（QY） as high as 22%. By virtue of their excellent optical properties， an UV-excited carbon dots-based pure white light emitting diode（WLEDs） was successfully constructed with a color coordinate of （0.33，0.33）， which is very close to that of natural sunlight. This study paves a new path for the large scale preparation of R-CDs with high QY， and broadens their application in luminescent devices.