Table of Content

10 August 2023, Volume 44 Issue 8

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Content

Cover and Content of Chemical Journal of Chinese Universities Vol.44 No.8(2023)

2023, 44(8):  1-6. 

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Review

Aqueous Fabrication and Biomedical Applications of Supraparticles

WANG Menglei, GONG Jianxiao, XIA Yunsheng

2023, 44(8):  20230020.  doi:10.7503/cjcu20230020

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Supraparticles（SPs） are the nano-entities self-assembled by one or multiple nanoparticle based on internal or external driving forces， which possess specific morphology， definite size， and hierarchical structure. Due to the complex topologies， abundant surface modifiability， tunable collective properties， and synergistic effects， SPs have considerable potentials in the biomedical field. Here， recent progress of SPs synthesized in aqueous phase， including the force modulation between building blocks， the property of SPs， and their applications in biological imaging， disease diagnosis， and therapy， is reviewed. Finally， the main challenges and future advancement in aspects of the precise regulation of the structure and properties of SPs， as well as biomedical applications are discussed.



Hollow-structured Nanomaterials for Biomedical Applications： Current Development and Future Prospective

ZHANG Lu, ZOU Yunhe, XU Zhongsheng, LIU Yun

2023, 44(8):  20230134.  doi:10.7503/cjcu20230134

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In recent years， hollow-structured nanomaterials have shown great advantages in a variety of applications in biomedical fields because of their unique structures cavities， widely sources and excellent magnetic， electronic， optical or catalytic properties. They are designed specially for loading drugs or imaging agents for the disease therapy， diagnosis and monitoring of treatment， which aim to protect and improve health conditions. This review summarized the research progress of different types of hollow-structured nanomaterials， and then these advanced multifunctional hollow structured nanomaterials with stimuli responsive drug release， multimodal therapy， theragnostic and imaging and treatment monitoring were commented， respectively. This article has been also explored the challenges and potential future directions of hollow-structured nanomaterials for biomedical applications.



Article: Inorganic Chemistry

Synthesis of EAB Zeolite and Its Application in Methanol-to-olefin Reaction

YANG Yingnan, SUN Qiming

2023, 44(8):  20230119.  doi:10.7503/cjcu20230119

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Methanol-to-olefin（MTO） reaction provides a new approach to produce light olefins via the non-petroleum route. The development of novel catalysts is the key to improve the performance of MTO reactions. In this work， the synthetic conditions and thermal stability of EAB zeolites with eight-membered rings were systematically investigated. The topological structure， crystal morphology， skeleton composition and acidity of the obtained EAB zeolites were characterized by X ray diffraction， scanning electron microscopy， inductively coupled plasma optical emission spectrometry， and ammonia-temperature programed desorption measurements. The structure of the EAB zeolite remained unchanged after calcination in air even at 550 ℃ when the K⁺ and Cs⁺ ions were introduced into EAB zeolite pores. Significantly， the crystallization rate can be accelerated and the impure crystalline phase can be suppressed by adding seeds to the synthesis system. The complete crystallization time can be shortened to 3 d. In addition， the EAB zeolite was used for the first time in the MTO catalytic reaction， and showed a high selectivity of ethylene， propylene and butene up to 87.2%. and a high selectivity ratio of propylene to ethylene up to 2.4. This work provides a reference for the development of new catalysts with adjustable selectivity of propylene and ethylene for MTO reactions.



Influence Mechanism of Impurity Silicon on Crystallization Process of Sodium Zincate Solution

LIU Pengfei, YOU Shaowei, ZHANG Yifei, TANG Jianwei, WANG Baoming, LIU Yong, HUA Quanxian

2023, 44(8):  20220767.  doi:10.7503/cjcu20220767

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Effect of impurity silicon on the crystallization process of sodium zincate solution was studied. Based on the crystal phase and thermodynamics analysis， the influence mechanism of impurity silicon on the structure of sodium zincate solution was obtained. The decomposition behavior of sodium zincate solution was analyzed. The effects of impurity silicon concentration， crystal seed and temperature on the crystallization process of sodium zincate solution were investigated. The results show that there is a critical silicon concentration. When the silicon concentration is higher than the critical silicon concentration， the impurity silicon inhibits the crystallization process； when the silicon concentration is lower than the critical one， the impurity silicon promotes the crystallization process. When zinc oxide is used as crystal seed， the critical silicon concentration at 35， 50， and 60 ℃ are in the range of 0.20—0.40， 0.054—0.20 and 0—0.054 g/L， respectively； when zinc hydroxide is used as crystal seed， the critical silicon concentration is in the range of 0.20—0.40 g/L at 35 ℃. The critical silicon concentration decreases with increasing temperature. When silicon content is low， the phase is ε-Zn（OH）₂ of polyhedron； when silicon content is high， the phase is γ-Zn（OH）₂ of nanorods and cuboids. Increasing the temperature can inhibit the formation of γ-Zn（OH）₂. The presence of silicon impurities may reorganize the structure of sodium zincate solution， and is conducive to the existence of zinc ions in the form of Zn（OH）⁺. The increase of temperature can reduce the influence of silicon impurities.



Melanin-based Targeted Nanodrugs for Photothermal Therapy of Breast Cancer

SUN Jinghua, GUO Chunyan, DONG Jie, ZHANG Ruiping

2023, 44(8):  20230044.  doi:10.7503/cjcu20230044

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To improve the targeting effect of small-sized melanin nanoparticles（MNP） at tumor sites， a hydroxyapatite hybrid mesoporous silica（MSN/HAP）， which is degradable in tumor micro-acidic environment， was designed and synthesized for loading， and a novel highly targeted nanodrug（MAN/HAP-MNP-RGD） was constructed in combination with RGD-directed peptide for multimodal imaging and photothermal therapy of mouse breast cancer. The physicochemical properties of nanoparticles， cellular and invivo experiments were examined and the results showed that the final particle size was approximately 60 nm， the loading of MNP was 37.7%， the nanoparticles showed good degradability in a slightly acidic environment， and the photothermal conversion efficiency of the nanoparticles was 40.29%. In addition， the results of photoacoustic imaging and magnetic resonance imaging showed that the nano- particles showed higher accumulation and longer retention time at the tumor site. Finally， the in vivo experiments demonstrated that MAN/HAP-MNP-RGD has the best therapeutic effect and high biosafety， showing potential applications.



Analytical Chemistry

Visualization of Protein-specific Glycosylation and Photodynamic Therapy via an Enzyme-free Amplification Strategy of Catalytic Hairpin Assembly and Hybridization Chain Reaction

LI Ting, XING Simin, LIU Yang

2023, 44(8):  20230140.  doi:10.7503/cjcu20230140

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Herein， a highly sensitive， enzyme-free signal amplification strategy based on the proximity-induced catalytic hairpin assembly and hybridization chain reaction（CHA-HCR） was developed for protein-specific glycosy-lation fluorescence imaging of cancer cells in situ and highly efficient photodynamic therapy. Two DNA probes were designed for the specific labeling of target proteins and glycans， respectively， where the protein probe（PP） identified the MUC1 protein by aptamer and the glycan probe（GP） specifically bound to sialic acid via bioorthogonal reaction. Due to the proximity effect， the CHA initiation sequence in the PP hybridized with the adjacent GPs and triggered a subsequent CHA-HCR cascade reaction. An extended double-stranded DNA strand with multiple fluorescent molecules or photosensitizers formed on specific glycosylation of the target protein， which provided a universal avenue for the multiple glycosylation imaging on the cancer cell surface with high sensitivity and a valuable way for photodynamic therapy with enhanced cytotoxic effect by targeting the specific glycoproteins. This strategy supplies the reference for uncovering the mechanism of glycosylation， screening glycan-related biomarkers and developing targeted therapies.



Organic Chemistry

Copper-catalyzed Synthesis of Amides from Alcohols and Aminopyridines Under Aerobic Conditions

YANG Wei, LIU Jiaqi, TANG Cuiman, ZHANG Haonan, WANG Bingbing, SUN Zhong, XU Xiaohui

2023, 44(8):  20230029.  doi:10.7503/cjcu20230029

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N-（pyridine-2-yl）amides were synthesized in one step with benzyl alcohols and 2-aminopyridines in copper-catalyzed aerobic conditions by air bubbling method. The mechanism study demonstrated that benzaldehydes were formed in situ from benzyl alcohols under aerobic conditions and acted as coupling partners to react with 2-aminopyridines to synthesize amides. The bioactivity study showed that the synthesized products possessed certain antibacterial activity. This reaction features high efficiency and functional group tolerance. Moreover， no additives were used in the reaction and this method utilized oxygen from the air as an ideal oxidant with the virtue of economy and green.



Synthesis and Anti-Toxoplasma Activity of Novel Tetrahydropyrido［4，3-d］pyrimidine Derivatives

LUAN Tian, CUI Sijiao, SUI Lili, SUN Chiyu, ZHANG Dajun

2023, 44(8):  20230098.  doi:10.7503/cjcu20230098

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To develop highly effective and highly selective anti-Toxoplasma drugs， twenty novel tetrahydropyridines［4，3-d］pyrimidine derivatives were designed and synthesized via the principle of pharmacochemical molecular combination. Ethyl 1-benzyl-4-oxo-3-piperidinecarboxylate hydrochloride as starting material， the target compounds 7a—7t were obtained by seven step reaction. All target compounds were characterized via nuclear magnetic resonance spectroscopy（¹H NMR， ¹³C NMR）， mass spectrometry and elemental analysis. Methyl thiazolyl tetrazolium（MTT） method was used to investigate the anti-Toxoplasm activity in vitro， and the compound with the best activity was selected to further quantify the inhibitory activity against Toxoplasm dihydrofolate reductase（TgDHFR）. The results showed that ten compounds had higher anti-Toxoplasma activity compared with the positive control drugs pyrimethamine and sulfadiazine. Compound 7p exhibited the most potent anti-Toxoplasma activity and commendable selectivity between TgDHFR and human dihydrofolate reductase（hDHFR） with half maximal inhibitory concentration（IC₅₀） value of 15 nmol/L against TgDHFR and 1460 nmol/L against hDHFR. Molecular docking experiments showed that compound 7p could be strongly bound to TgDHFR through five hydrogen bonds， which could be deeply studied to develop new anti-Toxoplasma drugs.



Catalytic Performance of ［Fe］ for Regioselective Ring-opening of Epoxides

YAO Yixuan, LU Changbo, ZHANG Hongwei, ZHANG Duxin, SHANG Hongyan, TIAN Yuanyu

2023, 44(8):  20230137.  doi:10.7503/cjcu20230137

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In this work， the ring-opening of epoxides was realized using cheap and abundant iron-based catalysts， in which Fe（BF₄）₂·6H₂O showed the best catalytic effects. The results showed that aldehyde could be obtained with high selectivity in this reaction. The ring-opening of 1，2-epoxyoctane in the presence of 0.01 mmol Fe（BF₄）₂·6H₂O was applied with 1，4-dioxane as solvent， the yield of octanal was up to 98% with a selectivity of 99%. Gratifyingly， this catalytic system was suitable for a variety of alkyl- and aryl-substituted epoxides. Furthermore， the recycling experiments showed that Fe（BF₄）₂·6H₂O could maintain excellent catalytic activities when reused for three times， but then deactivated dramatically at the fourth recycle. In order to further understand the reason of catalyst deactivation， Fourier Transform infrared spectoscopy（FTIR）， X-ray diffraction（XRD）， X-ray fluorescence（XRF） and thermal gravimetric analysis（TGA） were used to analyze the catalyst. It was found that the reason of deactivation was the loss of B and F elements during the reactions， which affected the structure of the catalyst， as well as the coordination ability with epoxides. These findings further proved the mechanism of this reaction and revealed the reason of deactivation， and also provided a theoretical basis for the efficient application of this type of catalysts in homogeneous systems.



Physical Chemistry

Preparation of Disodium Hydroquinone as Cathode Material for Sodium-ion Batteries

MENG Zhicheng, LU Yong, YAN Zhenhua, CHEN Jun

2023, 44(8):  20230158.  doi:10.7503/cjcu20230158

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Organic electrode materials are very promising for sodium-ion batteries because they have the advantages of abundant resources， environmental friendliness， recyclability， and high specific capacity against inorganic electrode materials. Among them， the organic electrode materials at reduced states can be matched with anode such as hard carbon， which makes them more promising for practical applications. However， the synthesis and application of organic cathode materials at reduced states for sodium-ion batteries are still challenging. Here we reported the successful synthesis of disodium hydroquinone and its application as cathode material for sodium-ion batteries. The synthesis was conducted by the reaction between sodium hydroxide and excess hydroquinone to generate monosodium hydroquinone， followed by heating to produce disodium hydroquinone and removing excess hydroquinone. This method is free of organic solvent， and exhibits the features of high utilization of raw materials and promises for large-scale production. When used as cathode material in sodium-ion batteries， disodium hydroquinone shows a discharge specific capacity of 182 mA·h/g at 0.1C in the first cycle. To mitigate the dissolution of disodium hydroquinone during charge/discharge processes， 6 mol/kg NaTFSI/DME was used as electrolyte， resulting in an improved capacity retention of 62% after 30 cycles. In contrast， the capacity retention is only 35% after 10 cycles in common 1 mol/L NaPF₆/G2 electrolyte. This work provides new insights into the preparation and sodium-ion battery application of sodiated organic cathode materials at reduced states.



Effect of Vacancy Defects on Thermal Decomposition Mechanism of NTO Crystals

NING Liyuan, LI Lijie, CHEN Kun, JIN Shaohua, LU Zhiyan

2023, 44(8):  20230055.  doi:10.7503/cjcu20230055

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A perfect crystal model containing 256 3-nitro-1，2，4-triazol-5-one（NTO） molecules and defects crystal models containing 0.78%， 1.17%， 2.34%， 3.13% and 5.10% vacancy content， respectively， were constructed to study the effect of vacancy defects on the thermal decomposition of NTO. The potential energy and products of the six models at 1500 K were calculated， respectively. The initial reaction paths and decomposition rates were analyzed. The results show that at 1500 K， there are four paths for the initial decomposition of NTO： NTO aggregates to produce clusters， C—NO₂ bond breaks to remove nitro， intermolecular proton transfer to cause ring opening and breaking（including C3—N4， N1—C5 bond fracture and C3—N4， N1—N2 bond fracture）. In the range of 0.78%—2.34% vacancy content， with the increase of defect content， the frequency of the four initial reactions increases， the protonation reaction advances， and the ring fracture reaction delays. When the defect content exceeds 2.34%， the existence of vacancy leads to crystal collapse， the frequency of four initial reactions decreases， and the frequency of complex reactions increases. The existence of vacancy defects accelerates the overall thermal decomposition process. The above research results can be used to guide the regulation of NTO thermal safety.



First-principles Study of Direct Z-scheme In₂SSe/Sb Heterostructure as Photocatalyst for Water Splitting

CAO Shengzhe, HUANG Xin, YANG Zhihong

2023, 44(8):  20230145.  doi:10.7503/cjcu20230145

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The photocatalytic properties of two-dimensional In₂SSe/Sb van der Waals heterostructure were investi-gated via first-principles method. The results show that In₂SSe/Sb heterostructure possesses the staggered band alignments with a direct band gap of 0.82 eV. As the built-in electric field is pointing from Sb to In₂SSe at the interface， the In₂SSe/Sb heterostructure exhibits type-Z mode， which is beneficial for effective electron-holes separations. Moreover， its band edges straddle water redox potentials and a strong optical absorption spectrum from visible light to ultraviolet light is obtained. Our study would offer theoretical understanding for designing In₂SSe/Sb van der Waals heterostructure.



Theoretical Calculation of Relationship Between Zeolite Confinement Effect and Adsorbed 2-¹³C-acetone ¹³C Chemical Shift

XIONG Wenpeng, CHU Yueying, WANG Qiang, XU Jun, DENG Feng

2023, 44(8):  20230063.  doi:10.7503/cjcu20230063

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The relationship between adsorbed 2-¹³C-acetone ¹³C chemical shift and zeolite confinement effect and acid strength（deprotonation energy， DPE） has been assessed by the quantum chemical calculation with the aim of decoupling the influence of acid site strength and zeolite confinement on the measured ¹³C chemical shift， both of which are key factors in zeolite catalysis. We found the hydrogen-bond complex exist for acetone adsorption independent of the location of the Brønsted acid sites. The calculational results show that although the ¹³C chemical shift of adsorbed acetone increases with the increase of zeolite intrinsic acid strength（DPE decreasing）， but a linear correlation is not present between them. For the Brønsted sites located in the zeolites with different pore sizes， the subtle difference in the DPE values would lead to significant differences in the ¹³C chemical shift， which demonstrated the zeolite pore confinement played a pivotal role in the measured ¹³C chemical shift in zeolite catalysis. The acetone adsorption energy increases with the decreasing of the zeolite pore size， which could reflect the strength of the zeolite pore confinement effect. Furthermore， a linear correlation is obtained for the ¹³C chemical shift of adsorbed acetone versus its adsorption energy， which can be used as a scale for quantitatively measuring the zeolite pore confinement effect.



Interfacial Engineering and Electrocatalytic Hydrogen Evolution Performance of Ni/TiO₂-V_O Nanowires Self-supporting Thin Films

ZHAO Huanyu, MI Hongtian, CHANG Yueqi, ZHOU Dongxue, ZHANG Liguo, YANG Mu

2023, 44(8):  20230057.  doi:10.7503/cjcu20230057

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In this paper， a self-supporting titanate nanowire thin film was synthesized by a hydrothermal method. After an ion exchange reaction and a high-temperature H₂/Ar（5%） mixture reduction， the Ni nanoparticles modified oxygen-rich vacancy TiO₂ nanowire self-supporting films（Ni/TiO₂-V_O NFFs） were obtained. During the high-temperature reduction in H₂/Ar atmosphere， abundant oxygen vacancies and low-coordinated Ti³⁺ sits were generated on the surface of TiO₂ nanowires， which lead to the improvement of the electrical conductivity of TiO₂ film. In addition， the strong interaction between Ni nanoparticles and TiO₂ optimized the electronic structure and promoted the electrocatalytic hydrogen evolution reaction（HER） activity. density functional theory（DFT） calculations revealed that Ni/TiO₂-V_O NFFs had optimal Gibbs free energy of hydrogen adsorption（ΔG_H*）. As a result， Ni/TiO₂-V_O NFFs exhibited an overpotential of 67 mV at 10 mA/cm² in 1 mol/L KOH solution and displayed excellent stability， showing great potential in the field of electrocatalytic HER.



Influence Factors on Induced Potential of Reduced Graphene Oxide-based Microfluidic Voltage Generations

GAO Weizhuo, JING Weixuan, DU Yanrui, LI Zehao, HAN Feng, ZHAO Libo, YANG Zhaochu, JIANG Zhuangde

2023, 44(8):  20230033.  doi:10.7503/cjcu20230033

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In this paper， reduced graphene oxide（rGO）-based microfluidic voltage generations were fabricated with the suspensions at different rGO concentration. Different values of the induced potential of these rGO-based micro- fluidic voltage generations were generated at various volume flow rate of NaCl solution. Based on Nernst-Planck equation the quantitative relationship between the Na⁺ ion concentration in the diffusion layer upon the surface of the working electrode and induced potential of the microfluidic voltage generation was established. With the values of induced potential corresponding to different volume flow rates of the NaCl solution， the effect of the volume flow rate on both mass transporting of Na⁺ ions from the solution upon the rGO membranes and the concentration of the Na⁺ ion adsorbed on the surface of working electrode， and further the induced potential of the rGO-based microfluidic voltage generation had been researched. Besides， by quantitatively characterizing the surface morphology of the rGO membrane with the surface texture aspect ratio（Str） and maxium height（Sz）， the relationship among the rGO concentration of the suspension， the surface morphology of the rGO membrane， the concentration of the Na⁺ ion adsorbed on the surface of the working electrode and the induced potential of the microfluidic voltage generation had been established. At volume flow rate 50 μL/min of the NaCl solution and rGO concentration 1.0 mg/mL of the suspension the rGO-based microfluidic voltage generation can generate an optimal induced potential -343 mV. These results benefit not only the fabrication and performance optimizations of other carbon-based microfluidic voltage generations， but also the behavior improvements of the microfluidic channel based photo-degradation reactors， ion sensing devices and electrochemical glucose sensors.



P-Modified Deactivated TS-1 as an Efficient Catalyst for Catalytic Cracking of Pentene to Ethene and Propene

XU Deyi, DING Chaojun, LI Fang, LIU Yueming, HE Mingyuan

2023, 44(8):  20230094.  doi:10.7503/cjcu20230094

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The development of catalytic cracking of pentene to ethene and propene has very important research significance and industrial application value. Its core is high-effciency catalysts. Here， deactivated titanium silicalite-1（De-TS-1） was developed as catalyst for catalytic cracking of pentene. And P-modified De-TS-1 shows excellent catalytic performance， the ethene and propene^{selectivity and single-run lifetime reach 77.1% and 213 h， respectively. Its comprehensive catalytic performance is better than that of the classical ZSM-5 catalyst. Further studies show that the Brønsted properties of De-TS-1 satisfy the basic requirements for high-efficiency cracking of pentene. P modification can further reduce the acid density and acid strength of Brønsted acid in De-TS-1， promoting the main reaction of the target products ethene and propene， and inhibiting the side reactions such as hydrogen transfer reaction and aromatics isomerization reaction during pentene cracking. This development of De-TS-1 as a high efficiency catalyst for pentene cracking process provides a new idea for the recycling of waste catalyst and a new scheme for the development of new solid acid catalyst.}



Effect of Acid Property Regulation on the Performance of Pd/MIL-100（Cr） Catalyzed One-step Oxidation of Benzyl Alcohol to Acetal

LI Zipeng, GENG Jiaxin, LIU Yingya, SUN Zhichao, WANG Yao, WANG Anjie

2023, 44(8):  20230059.  doi:10.7503/cjcu20230059

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MIL-100（Cr） was hydrothermally synthesized and used as a solid-acid catalyst support. Pd nanoparticles were impregnated on MIL-100（Cr） by a double-solvent approach followed by hydrogen reduction to obtain Pd/MIL-100（Cr）. One-step tandem conversion of benzyl alcohol to acetal was selected as a model reaction， and the influence of acid property of MIL-100 on the product distribution was investigated. The results showed that Pd/MIL-100（Cr） catalyzed tandem reaction could accelerate the benzyl alcohol oxidation， and different reduction and activation temperatures had an impact on the acid properties of MIL-100（Cr）， which in turn affected the selectivity of acetal. The acid properties were characterized by pyridine adsorption infrared spectroscopy（Py-FTIR） and temperature programmed desorption of ammonia（NH₃-TPD）， the result showed that increasing the catalyst treatment temperature， the L acid sites increased， the B acid sites decreased， and the B acid sites was beneficial to improve the selectivity of acetal. Under optimal conditions， a benzyl alcohol conversion of 99.9% and acetal selectivity of 76.2% can be achieved at 70 ℃ in 12 h. X-ray photoelectron spectroscopy（XPS） analysis was used to characterize the electronic properties of the Pd species and the MIL-100（Cr）， the cycling stability of the catalyst was investigated， and the reasons for the deactivation of the catalyst were analyzed by powder X-ray diffraction（XRD）， scanning electron microscopy（SEM）， N₂ adsorption-desorption isotherms and NH₃-TPD.



Facile Synthesis of Gold Nanoflowers and the Catalytic Reduction of p-Nitrophenol with Sodium Borohydride

FENG Ruiqin, FANG Yun, FAN Ye, XIA Yongmei

2023, 44(8):  20230027.  doi:10.7503/cjcu20230027

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Gold nanoflowers（Au NFs） were synthesized by facile one-pot strategy using the mixed aqueous solution of polyvinylpyrrolidone and sodium dodecyl sulfate as soft template and polyvinylpyrrolidone as in situ reductant as well. The particle size， morphology and crystal structure of Au NFs were characterized by transmission electron microscope， ultraviolet visible spectrophotometer and X-ray diffractometer. The experimental results show that the average equivalent diameter of the optimized Au NF is about 37 nm with the flower-like morphology due to ca. 10 nm protrusions densely distributed on the surface. The optimized Au NF is face-centered cubic crystal dominated by ｛111｝ crystal plane with characteristic localized surface plasmon resonance absorption at 560—570 nm. The Au NF shows excellent catalytic activity and cycle stability in the catalytic reduction of p-nitrophenol to p-aminophenol by sodium borohydride. The Au NF（0.83 mmol/L） can catalyze sodium borohydride（3.52 mmol/L） to reduce p-nitrophenol（0.12 mmol/L） completely within 10 min， and the reaction rate constant is 0.1846 min^-1， while the reduction efficiency of sodium borohydride（3.409×10^-3 min^-1） is 1.64—55.6 times higher than those reported in the literature. The Au NF can be reused for 10 times without prolonging reduction times to converse p-nitrophenol completely.



Polymer Chemistry

Dispersion of Carbon Black N134 in Different Rubber Systems and Its Mixing Process Regulation

HE Tiancheng, WANG Yuge, CHEN Siyuan, YIN Yuan, SUN Hongguo, ZHENG Yafang, SUN Zhaoyan

2023, 44(8):  20230093.  doi:10.7503/cjcu20230093

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The influence of mixing process on the properties of carbon black（CB， N134） reinforced isoprene rubber， styrene butadiene rubber and bionic rubber after cure was studied. Considering that the dispersion of CB in bionic rubber is poor compared to that in the other two systems， a new processing routine was designed to improve the dispersity of CB in bionic rubber， and the results show a good dispersity of CB and an enhanced performance of bionic rubber. Our study indicates that， with increasing internal mixing time， the dispersity of CB in isoprene rubber and styrene butadiene rubber is improved from about 1 grade to higher than 6 grade， while that in bionic rubber still remains a low grade（around 1 grade）. Further increasing the internal mixing time does not greatly improve the dispersity of CB in bionic rubber system. To solve this， mastication and mill banding were introduced and the dispersion of CB was greatly improved in bionic systems. As expected， with increasing the dispersity of CB in rubber systems， the tensile fatigue life was enhanced， as verified by all the three studied rubber systems. For bionic rubber， a certain time of mastication will decrease the Mooney viscosity and the molecular weight of gum， leading to an enhanced processability. Moreover， Payne effect in vulcanized bionic rubber was also increased with increasing the mastication time. This is probably due to the fact that the improvement of dispersion of CB in rubber matrix increases the specific area of CB agglomerates， which brings more bound rubber to enhance the interfacial adhesion between fillers and rubber matrix.



Single-molecule Force Spectra of Three Typical Semi-aromatic Polyesters

WAN Pengcheng, LU Song, BAO Yu, CUI Shuxun

2023, 44(8):  20230126.  doi:10.7503/cjcu20230126

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The single-chain mechanical properties of three typical semi-aromatic polyesters（polyethylene terephtha-late， polytrimethylene terephthalate， and polybutylene terephthalate） were studied by single-molecule force spectroscopy. The single-chain force-extension curves of these three polyesters obtained in the same liquid environment can be overlapped well， indicating that the small difference in the number of methylene has no significant effect on the inherent elasticity and hydrophilicity of polyesters. This may be because the polyester molecules are very similar in structure and all adopt the random chain conformation in solution. The single-molecule results imply that the differences in physicochemical properties of polyester materials may be due to the changes in the arrangement of chain segments and intermolecular forces when the polymer chains aggregate to form crystals. It is expected this study will provide some theoretical support for the property regulation of polyesters.



Environmental Responsive Adhesion Behavior of Metal Ion Crosslinked Thermosensitive Double Network Hydrogel

CHEN Shunlan, XU Danni, LI Xuefeng, PENG Gege, HUANG Yiwan, LONG Shijun, ZHANG Gaowen

2023, 44(8):  20230192.  doi:10.7503/cjcu20230192

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A thermally responsive double-network hydrogel（TDN） with environmental response adhesion was prepared by the “one-pot method”， and it was found that TDN_87.5 hydrogel had the best shear bond strength（26.53 kPa）. Further introducing metal ion coordination crosslinking TDN_87.5 thermal hydrogels with multiple valence states， it was found that the tensile strength increased by more than 1 times（from 172.46 kPa of TDN_87.5 hydrogel to 373.72 kPa of TDN_87.5-Zr hydrogel）， and the corresponding shear bond strength increased by about 16 times（from 26.53 kPa to 447.29 kPa）. Furthermore， by adjusting the concentration， time and temperature of soaking Zr⁴⁺， a TDN_87.5-Zr_0.3@90 ℃ hydrogel with the best shear adhesion strength（552.62 kPa） was obtained， and the principle of regulating the adhesion behavior of TDN thermal hydrogel by multiple methods was discussed， which provided a new idea for the development of a new hydrogel with high strength， high interfacial adhesion performance and controllable shape deformation.



Bionic Preparation and Characterization of Superhydrophilic Functional Surface Based on Shark Skin Mucus Secretion

LIU Yunhong, PENG Xinyan, LIU Xiaolong

2023, 44(8):  20230089.  doi:10.7503/cjcu20230089

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The skin of sharks exhibit superhydrophilic and underwater superoleophobic properties through the continuous secretion of mucus. Inspired by this， we propose a simple route to create superhydrophilic surface through the introduction of hydrophilic modifiers into the polymer matrix， simulating the secretion of shark skin mucus by means of spontaneous migration of hydrophilic modifiers onto the polymer surface. In this paper， polyethylene glycol type nonionic surfactants were selected as hydrophilic modifiers， which were firstly mixed with polyurethane acrylate prepolymer， after that， the mixture was cured by UV radiation to obtain the bionic functional surface. Research results showed that the introduction of hydrophilic modifiers such as Tween 20， Tween 40， Tween 60， Tween 80 or Triton X100 into the UV-curable polyurethane system can obtain superhydrophilic surface with stable self-repairing function， excellent light transmittance， antifogging and oil-water separation effects. This method is simple， cost-effective， and environmentally friendly， which provides a new idea for the design and preparation of bionic superhydrophilic surface， and therefore， it is expected to be effectively used in biomedical coatings， oil-water separation， antifouling coatings， etc.



Regulation of TBIR on the Structure and Properties of Natural Rubber Based Nanocomposites

QIAN Zhehao, WANG Shuo, ZONG Xin, CAI Lei, HE Aihua

2023, 44(8):  20230023.  doi:10.7503/cjcu20230023

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Trans-1，4-poly（butadiene-co-isoprene） copolymer rubber（TBIR） and wet mixing natural rubber masterbatch（W-NR） were used to modify natural rubber（NR） nanocomposites with different polymer network structures and filler network structures. The structure and properties of NR， NR/W-NR， NR/TBIR and NR/W-NR/TBIR rubber nanocomposites were investigated by means of carbon black packing dispersion apparatus， differential scanning calorimetry and equilibrium swelling method， etc. Compared with NR and NR/W-NR vulcanizates， the addition of TBIR component constructed special polymer network structures including sulfide bonds and polymer crystals acting as physical crosslinks in the NR matrix， which improved the modulus and green strength of the NR matrix， provided better filler dispersion， and improved filler-rubber interactions. Therefore， compared with NR and NR/W-NR vulcanizates， the NR/TBIR（90/10） and NR/W-NR/TBIR（40/66.5/10） vulcanizates showed improved DIN abrasion resistance， enhanced tensile fatigue property， reduced rolling resistance， and better aging resistance. The NR/W-NR/TBIR（40/66.5/10） vulcanizate prepared by combining the advantages of W-NR and TBIR together presented much lower rolling resistance， as well as excellent comprehensive properties. This work provides a facial and effective regulation way to adjust the polymer network structure and filler network structure， and fabricate NR nanocomposites with excellent comprehensive properties.



Thermal Stability and Mechanical Properties of the Composite of Epoxy Resin with Ammonium Polyphosphate/Ceramic Precursor Modified Bamboo-based Porous Carbon as Synergistic Flame Retardant

WANG Fang, HAO Jianwei

2023, 44(8):  20230030.  doi:10.7503/cjcu20230030

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Green， low cost and high performance have always been the challenges of material preparation. The porous bamboo-based carbon material（MPCM） modified by silicon boron ceramic precursor was prepared by the reaction of silane coupling agent（hydrolysate silanol） and boric acid in this paper. Among them， the limiting oxygen index of epoxy resin（EP） modified by γ-glycidyl ether oxypropyl trimethoxysilane（KH560）， boric acid MPCM（M6PCM， mass fraction 1.6%） and ammonium polyphosphate（APP， mass fraction 6.2%）（EP/APP/M6PCM） reached 31.1%， the peak heat release rate decreased by 60%， and the residual char increased by 12.7%， the glass transition temperature was increased to 136 ℃， and the storage modulus reached 3319 MPa. The mechanism study showed that the silicon boron ceramic precursor on the surface of M6PCM expedited the removal of H₂O and NH₃ from APP to form polyphosphoric acid， and promoted the formation of ceramic-like carbon and the transformation of graphite-like carbon. Compared with the results of relevant literature published in recent years， APP/M6PCM system shows cost advantages while improving the properties of EP composites.