Table of Content

    10 June 2023, Volume 44 Issue 6
    Cover and Content of Chemical Journal of Chinese Universities Vol.44 No.6(2023)
    2023, 44(6):  1-6. 
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    Hydrogel-based Bioinspired Ion Channels: Fabrication and Controllable Ion Transport
    CHEN Weipeng, KONG Xiangyu, WEN Liping
    2023, 44(6):  20220772.  doi:10.7503/cjcu20220772
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    The controllable ion transport is the basis of most physiological activities, such as the transmission of neural signals, the perception of external stimuli, etc. The key to realize the controllable ion transport is the various protein ion channels in life system. Inspiring researchers endeavor to develop artificial ion channels to subtly tune the ion transportation. Among the developed ion channels, hydrogel-based system exhibits the advantages of high ion selectivity and high ion conductance due to its three-dimensional(3D) charged networks induced space charges and 3D interconnection channels. As hydrogel-based ion channels hold the biocompatibility, deformability, and stable ion storage properties, it has been the focus in intelligence ion transport field and shows great potential in ion electronic circuits, medical health, energy conversion and storage, resources, and environment. To summarize the latest development of the hydrogel-based ion channels, we firstly overview on the construction methods of hydrogel-based intelligent ion channels. Thereafter, the ion transport mechanisms in the hydrogel-based ion channels are summarized, and the applications of such ion channels are categorized. At last, we discuss the existed issues and give the perspective on future development of hydrogel-based ion channels.

    Articles: Inorganic Chemistry
    Construction and Adsorption Properties of an Amide-based Cu-MOF
    LIU Jinlu, GUO Jiayu, HUA Jia, LI Guanghua, SHI Zhan, FENG Shouhua
    2023, 44(6):  20220746.  doi:10.7503/cjcu20220746
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    A novel metal-organic framework, [Cu(C14H7N2O5)]·5H2O·DMF, was synthesized by solvothermal method with inorganic copper salt and 5-(isonicotinamide) mbenzoic acid as starting materials. The microstructure and basic physical and chemical properties of the compound were characterized by means of single crystal X-ray diffraction(SCXRD), thermogravimetric analysis(TG), Fourier transform infrared spectroscopy(FTIR), as well as gas adsorption and separation. Single crystal diffraction analysis showed that the compound has a 3D structure consisting of Kagome layered structure. Nitrogen isothermal adsorption-desorption test showed that the compound has a high BET surface area of 889.21 m2/g and permanent porosity. The gas separation ratio of the compound is calculated to be 5.52 by the ideal adsorbed solution theory(IAST), indicating that the compound could effectively separate CO2/CH4 gas.

    Asp-induced Biomimetic Synthesis and Property of Candy-like Calcium Carbonate
    LIU Gaoyuan, LIU Yuehan, ZHAO Lina, GUO Yupeng
    2023, 44(6):  20220769.  doi:10.7503/cjcu20220769
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    The aspartic acid(Asp) was used as the inducer and candy-like calcium carbonate particles were prepared by controlling the reaction conditions such as reaction time, the dosage of inducer, and the reaction temperature, and the optimum conditions for obtaining the candy-like calcium carbonate particles were obtained. The structure, morphology and properties of the resulting calcium carbonate particles were characterized and a reasonable reaction mechanism was proposed. The new ideas about the preparation of calcium carbonate with specific morphology will be instructive in related material researches.

    Analytical Chemistry
    Understanding the Water Structures in Deep Eutectic Solvents by Near-infrared Spectroscopy
    WANG Yan, CAI Wengsheng, SHAO Xueguang
    2023, 44(6):  20230017.  doi:10.7503/cjcu20230017
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    The hydrogen bond network structure of choline chloride/urea deep eutectic solvents(DESs)-water mixtures was studied in the range of 5%—95% water content by near infrared spectroscopy. Through the analysis of the near-infrared spectra after choline chloride and urea mixing, the spectral feature of the interaction between urea —NH group and choline chloride Cl- was found, indicating that the formation of NH···Cl- was the reason for the decrease of DESs melting point. Through the near-infrared spectrum analysis of DESs-water mixtures with different water contents, the spectral information of the interaction between water molecules and between water molecules and the —NH and C=O groups in urea was found. Water mainly exists in three kinds of structures, including the bulk water, the hydrated water with urea C=O and the bridge water connect —NH groups. The bulk water destroyed NH···Cl- in DESs, reducing the stability of the system, while the bridge water between urea —NH molecules and the hydrated water with urea C=O increase the stability of the system. The relative content of the three water structures in DESs is related to the water content. The water content of 40%—80% can not only effectively reduce the viscosity of the system, but also maintain the properties of DESs.

    Nonylphenol Molecularly Imprinted 2D Photonic Crystal Hydrogel Sensor
    WANG Gang, LIU Genqi, ZHAO Lingli, WANG Yue, LIU Lisha, SUN Chenxin, MA Xiaoyan
    2023, 44(6):  20220757.  doi:10.7503/cjcu20220757
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    A molecularly imprinted two-dimensional photonic hydrogel sensor that can specifically recognizes nonylphenol(NP) was obtained by UV photoinitiated polymerization using polystyrene two-dimensional photonic crystal as template, NP as imprinted molecule, methanol as solvent, methacrylic acid as functional monomer, ethylene glycol dimethacrylate(EGDMA) as crosslinker, and 2,2-diethoxyacetophenone(DEAP) as initiator. The response performance of the sensor was determined by measuring the change in the diameter of the Debye diffraction ring(ΔD). In the NP solution, the volume expansion of the hydrogel leads to the increase of the particle spacing of the photonic crystal in the gel, which leads to the decrease of the diameter of Debye diffraction ring. As the concentration of NP in the solution increases from 0 to 1×10‒5 mo/L, the diameter of Debye diffraction ring decreases by 8.0 mm, and the particle spacing of the corresponding photonic crystal increases by 25.1 nm. In the NP concentration range of 1×10‒13—1×10‒8 mol/L, the change of Debye diffraction ring is linearly related to the logarithm value of NP concentration(lgc). In addition, the detection limit of NP molecularly imprinted two-dimensional photonic crystal hydrogel sensor is as low as 1×10‒13 mol/L, which has high sensitivity, good specificity recognition ability and stable reusability, and can realize the visual detection of nonylphenol.

    Sensitive Detection of L⁃Arginine Using Peptide Aptamer Functionalized Nanochannel
    CAO Zhong, GUO Peixian, XUE Shulei, XIAO Zhongliang, TAN Shuqi, KANG Xuan, FENG Zemeng, YIN Yulong, MA Tianji
    2023, 44(6):  20220758.  doi:10.7503/cjcu20220758
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    Amino acids are the source of life, in which L⁃arginine(L⁃Arg) is not only an important amino acid for metabolism in organisms, but also one of the important tumor markers. It is very important to develop highly selective methods for the detection of L⁃Arg in the field of bioanalysis. The polypeptide sequence specifically binding to L⁃Arg (sequence CFGHIHEGY) was screened from 29185 protein sequences in Uniprot database and was immobilized on the tip surface of bullet shaped nanochannel as a recognition element. Under the nanoconfined effect, the conformational change from extended state to curled state before and after the specific binding of peptides to L⁃Arg was used to control the effective pore size of nanochannel, resulting in the change of nanopore conductivity, which realize the selective detection of L⁃Arg. The experimental results show that the polypeptide modified nanochannel has high sensitivity and selectivity for L⁃Arg, the linear range is 1—100 nmol/L, and the limit of detection is as low as 1 nmol/L. This research provides a new method for sensible and highly selective amino acid sensing and also provides a new idea for designing peptide functionalized bio-inspired ionic channel.

    Organic Chemistry
    3-Quinoline Boric Acid as an Efficient Catalyst for the Direct Amidation of Carboxylic Acids at Room Temperature
    HUANG Dingmin, SUN Haotian, WANG Zhenwei, LIU Hao, SU Xianbin
    2023, 44(6):  20230004.  doi:10.7503/cjcu20230004
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    3-Quinoline boric acid had been identified as an inexpensive and effective catalyst for the direct dehydrative amide formation of carboxylic acids and amines. The catalyst was applicable to a wide range of carboxylic acids with primary and secondary amines to afford amides in moderate to good yields at room temperature. The catalyst also showed good catalytic activity to some aromatic and heteroaromatic carboxylic acids under higher temperature. This protocol provides a new methodology for the green boron-catalytic amidation under mild conditions.

    Near-infrared Light-driven Mucus-inert Janus Nanomotors for Efficient Mucus Penetration
    LIU Ling, JI Fa, YU Linling, SUN Yan
    2023, 44(6):  20220759.  doi:10.7503/cjcu20220759
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    The mucus layer is a crucial immune barrier located on the mucosal epithelial surface, which adheres foreign particles through the electrostatic and hydrophobic interactions, and thus hinders the mucus penetration of drug-loaded nanoparticles. Herein, a near-infrared-driven mucus-inert Janus nanomotor(JMSNs-pCBMA) was synthesized for the transmucosal delivery, based on the mesoporous silica nanoparticles, super hydrophilic zwitterionic poly carboxybetaine methacrylate(pCBMA) grafting, and gold depositing on the half surface. The transmission electron microscopy(TEM), Fourier transform infrared spectrophotometer(FTIR), energy dispersive X-ray spectrometry(EDX) and thermogravimetric analysis showed that JMSNs-pCBMA was synthesized with hydrodynamic size of (329±14) nm and pCBMA grafting density of 0.114 g/g. JMSNs-pCBMA exhibited the excellent ability to increase temperature rapidly under near-infrared light irradiation. The mucus-containing Transwell experiments showed that both of the pCBMA grafting and near-infrared light irradiation improved the permeability of nanomotor in mucus, and penetration percentage of JMSNs-pCBMA in mucus reached 52.4% in 4 h with an apparent permeability coefficient of 21.9×10-6 cm/s. In addition, the speed of JMSNs-pCBMA in mucus under near-infrared light irradiation reached 3.28 μm/s. In vitro cell experiments showed that JMSNs-pCBMA had good biocompatibility and could be endocytosed effectively by Calu-3 cells. In conclusion, a novel near-infrared light-driven nanomotor with fast mucus penetration and effective mucosal epithelial cell uptake was obtained for transmucosal delivery, and the experimental results would benefit the design and application of nanocarriers in the diagnosis, treatment and imaging of mucosal-related diseases.

    Catalyst-free and Efficient Synthesis of Disulfanes
    ZHU Yingying, YAN Xiaoyu, YU Jing, MAN Wenxin, LIU Feng, ZHOU Ying, MA Xiantao
    2023, 44(6):  20230045.  doi:10.7503/cjcu20230045
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    A catalyst-free, smell-less and efficient synthesis of disulfanes was developed from the reaction of phenylhydrazines and elemental sulfur under air atmosphere. This new method could tolerate various functional groups such as —F, —Cl, —Br, —NO2, —CF3 and —MeO groups, and could be easily extended to the synthesis of other aryl disulfanes such as 2-naphthyl disulfane and 2-pyridyl disulfane. Compared with the reported methods, this new method required no transition metal catalysts, no stoichiometric amount of oxidants, and no smelly and sophisticated sulfur reagents, showing good practical value.

    Syntheses of Polysubstituted Thiophene Derivatives via One-pot Multi-component Reaction
    REN Chuanqing, JI Xiaohui, JI Jianwei, ZHANG Qiang
    2023, 44(6):  20230073.  doi:10.7503/cjcu20230073
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    Thiophene skeleton exists in ticlopidine, olmutinib and tinoridine drugs, they can be used as antithrombotic drugs, antitumor drugs, anti-inflammatory analgesics. At present, the study on the modification of skeleton molecules of these compounds is one of the researched hotspots of pharmaceutical synthesis. In this paper, a novel synthetic method of polysubstituted thiophene derivative by one-pot multi-component reaction was reported. In the presence of K2CO3, 1,3-dicarbonyl compounds reacted with carbon disulfide, bromoethane and bromoacetonitrile. Their compositions and structures were characterized by nuclear magnetic resonance(1H NMR, 13C NMR) and high resolution mass spectrometer(HRMS). The mechanism for the reaction was proposed. The method had the advantages of mild conditions, safe operation and higher yields.

    In(OTf)3-catalyzed Intermolecular [3+2+1] Cyclization of Two Imine Units
    NAN Jiang, LIU Shilei, HUANG Guanjie
    2023, 44(6):  20220714.  doi:10.7503/cjcu20220714
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    A facile In(OTf)3-catalyzed [3+2+1] annulation reaction between imine units was developed, which represents a novel chemical transformation with imines. In this conversion, 23 kinds of structurally diversified acridine derivatives were rapidly obtained in moderate to excellent yields. This protocol features broad substrate scope and excellent functional groups tolerance, giving a new platform for preparing acridines widely used in the program of photoelectric materials.

    Influencing Factors and Mechanism of Dehydration Product Formation During Hydroxylmethylation of Fluorene to 9-Fluorenylmethanol
    LIU Junli, YE Cuiping, GUO Meixin, LI Wenying
    2023, 44(6):  20220701.  doi:10.7503/cjcu20220701
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    During one-step synthesis process of 9-fluorenylmethanol with paraformaldehyde as hydroxymethylation reagent, 9-fluorenylmethanol is easy to undergo base-catalyzed β-elimination(E1cb) to yield dibenzofulvene, and the selectivity of 9-fluorenylmethanol decreased. To achieve the process of regulation and control, the factors affecting the dehydration of 9-fluorenylmethanol, such as temperature, the types of alkali and ethanol and paraformaldehyde were investigated. The mechanism of by-product formation in the process of hydroxymethylation of fluorene to form 9-fluorenylmethanol was speculated according to the experimental results, kinetic calculation and isotope tracing. The results showed that increasing the temperature and alkalinity, and adding formaldehyde promoted the dehydration reaction. Ethanol promotes dehydration reaction through hydrogen bonding, and a large amount of ethanol would lead to the internal protonation of fluorenyl anion and 9-fluorenylmethanol anion. The intermediate may have the behavior of intramolecular hydrogen transfer or intermolecular hydrogen capture from fluorene and 9-fluorenylmethanol, facilitating dehydration reactions.

    Continuous Flow Synthesis of Structurally Symmetrical N-aryl 4-Pyridinones via a Multicomponent Tandem Reaction
    YANG Qi, LI Weiqiang, HUANG Shuntao, LI Jingpeng, LIU Teng, HUANG Chao
    2023, 44(6):  20220671.  doi:10.7503/cjcu20220671
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    A concise and efficient approach involving multicomponent tandem reaction to the synthesis of structurally symmetrical N-aryl-4-pyridinone derivatives utilized by continuous flow technology was developed. N-aryl-4-pyridones(24 examples) were synthesized using this practice protocol. The significant benefits of this method are three cheap and easily available raw materials, such as aromatic amines, triethyl orthoformate and 3-oxo-pentanedioic acid dialkyl ester, ethanol as solvent, catalyst-free reaction under mild conditions, short reaction times(20—90 min). It is worth noting that compared with the traditional batch reaction, this method has simple operation and high yield, and the product only needs to be recrystallized without column chromatography separation, which provides a new scheme for the preparation of symmetrical N-aryl-4-pyridone compounds.

    Physical Chemistry
    Light-driven Ammonia Synthesis over Layered-double- hydroxide-derived Ru Catalyst
    BIAN Xuanang, ZHOU Chao, ZHAO Yunxuan, ZHANG Tierui
    2023, 44(6):  20230095.  doi:10.7503/cjcu20230095
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    The metal oxide nanosheet-supported Ru nanoparticles(MgAlRu-500R) were prepared via calcining the Ru-based layered double hydroxide(MgAlRu-LDH) in a reductive atmosphere. X-Ray diffraction(XRD), high resolution transmission electron microscopy(HRTEM), X-ray photoelectron spectroscopy(XPS) and ultraviolet- visible-near-infrared diffuse reflectance spectroscopy(UV-Vis-NIR DRS) were employed to characterize the crystal structure, morphology, component and optical properties of MgAlRu-500R. The photothermal catalytic performance of MgAlRu-500R for ammonia synthesis was investigated in a flow-type reaction system at normal pressure. The results demonstrated that MgAlRu-500R can be heated up to more than 300 ℃ by light illumination as sole energy source and drived the photothermal catalytic ammonia synthesis reaction. Notably, MgAlRu-500R delivered a high ammonia production of 3.0 mmol·g‒1·h‒1 at 380 oC, markedly exceeding that of thermocatalytic process at the same temperature(1.5 mmol·g‒1·h‒1). Furthermore, in-depth kinetic analysis(determinations of apparent activation energy and kinetic reaction order) attributes the outstanding catalytic activity to the reduced activation energy caused by photoexcitation-accelerated N2 dissociation. This work provides a highly active catalyst with simple preparation method for photothermal ammonia synthesis, which will promote the development of green ammonia synthesis technology.

    Determination of the Nucleation Kinetics of Lithium Carbonate by Induction Period Measurement
    CHENG Wenting, LI Qianqian, CHENG Huaigang, CHENG Fangqin
    2023, 44(6):  20230074.  doi:10.7503/cjcu20230074
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    Nucleation kinetics was investigated by induction period measurement for supersaturated solutions of lithium carbonate(Li2CO3) in the LiCl-Na2CO3 system with and without NaCl over the temperature range of 288.15—323.15 K. The supersaturation of Li2CO3 was rigorously determined by full speciation model through OLI stream analyzer software. The effects of temperature, supersaturation and presence of NaCl on the nucleation induction period of Li2CO3 were studied experimentally. The nucleation kinetic parameters such as activation energy, interfacial tension and contact angle were calculated according to the classical theory of primary nucleation. The induction period was prolonged by adding NaCl in solutions at a constant supersaturation. The activation energy of Li2CO3 nucleation reaction increased from 63.69 kJ/mol(the excess of Cl ions Y=0) to 72.85 kJ/mol(the excess of Cl ions Y=0.5) after the addition of NaCl, indicating that the addition of NaCl inhibited the nucleation of Li2CO3. Classical theory of primary nucleation was used to study the homogeneous and heterogeneous nucleation mechanism of Li2CO3. The interfacial tension of homogeneous nucleation was higher than that of heterogeneous nucleation. Both interfacial tensions of homogeneous and heterogeneous nucleation had no significant dependence on temperature, and were not obviously influenced by the presence of NaCl.

    Efficient Oil-water Separation at the g-C3N4/TiO2-PVDF Photoresponsive Membrane Interface: Permeability and Selectivity Differences Induced by Different Exposed Crystal Planes and Performance
    ZU Peng, YUAN Pengcheng, WANG Shuguang, SUN Xuefei
    2023, 44(6):  20230085.  doi:10.7503/cjcu20230085
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    Membrane technology is constrained by membrane fouling of oil droplet obstruction in oil-water separation. A crucial step toward effective oil-water separation is the construction of a functional interface for selective separation of the oil-water mixture. In this paper, g-C3N4/TiO2-PVDF(polyvinglidene fluoride) photocatalytic membranes with different exposed crystal planes of TiO2 were prepared, and the effects of different exposed crystal planes on oil-water separation were studied. The experimental results show that the TiO2(001) surface endows the g-C3N4/ TiO2(001)-PVDF membrane with excellent superhydrophilicity and underwater superoleophobicsuperoil transport properties under sunlight irradiation, and compared with the TiO2(101) surface exposed membrane, g-C3N4/ TiO2(001)-PVDF membrane has better oil-water separation performance. Under visible light, the pure water flux of g-C3N4/TiO2(001)-PVDF membrane reaches 2002.9 L·m‒2·h‒1, which is 60.8% higher than that of g-C3N4/TiO2(101)- PVDF membrane, and 47.1% higher than that under dark conditions. Simultaneously, the rejection efficiency of the five kinds of oil substances is more than 99%, and the high permeation flux of 420.4—665.2 L·m‒2·h‒1 is maintained. The highest rejection efficiency of g-C3N4/TiO2(101)-PVDF membrane is only 61.8%, and the permeation flux is less than 200 L·m‒2·h‒1. The mechanism of different crystal planes was explored by transient photocurrent response and electron paramagnetic resonance technology. The results showed that the g-C3N4/TiO2(001)-PVDF membrane had a stronger light response current and more hydroxyl radical production. The permeation flux of g-C3N4/TiO2(001)-PVDF membrane was still 264 L·m‒2·h‒1 after a 360 min continuous experiment. High rejection efficiency and permeation flux were always maintained in the 8 cycles of regeneration experiments. Obviously, the photocatalytic membrane with exposed TiO2(001) has a greater permeability, selectivity, and stability, which is more appropriate for the effective separation of oil-water wastewater.

    Fabrication of Copper-doped Porous NiO Heterogeneous Catalyst and Its Application in Aerobic Oxidation of Benzyl Alcohol
    HOU Junying, HOU Chuanyuan, HAO Jianjun, LI Jianchang, WANG Yaya
    2023, 44(6):  20230042.  doi:10.7503/cjcu20230042
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    A copper-doped porous NiO heterogeneous catalyst was successfully fabricated by a metal-ion exchange method. The catalyst was characterized by SEM, XRD, FTIR, TGA. The SEM results showed that copper-doped NiO uniformly distributed with a flower-like structure; the XRD and FTIR results showed that the crystal structure of copper-doped NiO was the same as NiO; the TGA results showed that the stability of copper-doped NiO was better than that of Ni-MOF. The copper-doped NiO was evaluated as a catalyst for the aerobic oxidation of benzyl alcohol. 99% conversion of benzyl alcohol and 99% selectivity of benzaldehyde were obtained, at the same time, the copper-doped NiO heterogeneous catalyst still has an excellent stability after 5 cycles.

    Study on Nitrogen-doped PtCo/C Alloy Catalyst
    ZHAO Qian, LI Shang, CHENG Kuangwei, WEN Zhiyong, ZHANG Xiaoyu, YI Shaojie, PAN Mu
    2023, 44(6):  20230016.  doi:10.7503/cjcu20230016
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    The modification of alloy catalysts to achieve the activity required for the commercialization of proton exchange membrane fuel cells(PEMFCs) has attracted extensive attention in recent years. The performance of PtM (M=transition metal) nanomaterials as catalysts for oxygen reduction reaction(ORR) in PEMFC is higher than that of pure Pt, but there is room for improvement. Nonmetallic elements have a good affinity with platinum and can be added to catalysts. In this study, the activity and stability of the catalyst were enhanced by adjusting the content of nitrogen atoms in commercial PtCo/C. Finally, the MA of the catalyst was increased twice as much as before modification, the half-wave potential increased from 0.90 V to 0.93 V, and after 5000 cycles between 0.6 V and 1.0 V, the drop of half-wave potential decreased from 66 mV to 26 mV, showing excellent ORR activity and stability. The improvement of the activity was mainly attributed to the decrease of the adsorption binding energy of the oxygen- containing intermediates and the increase of the desorption rate of the hydroxyl group in the ORR process. The improved durability indicates that the presence of Pt—N bond makes the catalyst less likely to dissolve during the cycle, which contributes to the stability of the alloy catalyst on the carbon support. This experiment provides an effective treatment strategy for improving the activity and durability of alloy catalyst.

    Effect of Water Flooding at Different Positions of Cathode Side on the Performance of Proton Exchange Membrane Fuel Cell
    CHEN Yafeng, ZENG Liuli, GUO Wei
    2023, 44(6):  20230003.  doi:10.7503/cjcu20230003
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    The discharge of the water generated by the cathode of the fuel cell is mainly related to the catalytic layer, carbon paper, microporous layer and flow channel. The accumulation of generated water in these four parts will cause flooding. However, it is difficult to distinguish which part of the water flooding is caused by the accumulation during the operation of the fuel cell. In this paper, hydrophilic and hydrophobic treatment was carried out on different parts of the cathode side(catalytic layer, carbon paper, microporous layer, flow passage) to obtain local flooding in different parts. Then, the flooding situation of fuel cells was analyzed under different stoich, humidity, back pressure and other conditions. The test results show that with the decrease of stoich, the performance of the battery without hydrophobic treatment in carbon paper is the most serious decline, and the impedance arc radius of the battery is increased by 1.5 times. When the cathode was humidified at 10%, the performance of the cells without hydrophobic treatment in carbon paper and flow passage was poor, and the impedance are radius of the two cells was 50% larger than that of the cathode humidified at 60%; when the cathode is 100% humidified, the performance of the cell without hydrophobic treatment in carbon paper is the best, while that of the cell without hydrophobic treatment in the catalytic layer is the worst, and the impedance arc radius of the cell without hydrophobic treatment in the catalytic layer is twice as large as that of the cell with 10% humidification. With the decrease of back pressure, the performance of the cell without hydrophobic treatment of carbon paper decreased the most seriously, and the impedance arc radius of the cell under high back pressure was 50% smaller than that under low back compression.

    Photocharging Storage Capacity of C-rich Polymeric Carbon Nitrides Enhanced by TiO2
    WANG Xihui, TANG Xiao, LIU Tingting, LI Yanhong, JING Chuan, LING Faling, LIU Jun, ZHOU Xianju, YAO Lu, ZHOU Heng, ZHANG Jiazhong
    2023, 44(6):  20230028.  doi:10.7503/cjcu20230028
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    The light-induced accumulation of long-lived trapped electrons within the conjugated heptazine backbone enables polymeric carbon nitrides the dual ability of light absorption and charge storage. However, the photocharge storage capacity of C-rich polymeric carbon nitride(CPCN) has still been plagued by the severe recombination of photogenerated electrons and holes, which causes by its poor conductivity and low electron mobility. Herein, in order to enhance the photocharge separation, TiO2 was used to build an interfacial heterojunction with CPCN. Serving as the electron transporter, the used TiO2 nanocrystalline mesoporous film has high specific surface area of 220.03 m2/g. The electrode reaction activity is significantly improved by increasing the interface area between TiO2 and CPCN. Owing to the desirable hole-extraction route for the CPCN photo-rechargeable cell, a remarkable photo-charging capacity of 197 C/g is achieved. The photoelectrode is prepared by coating the CPCN material on top of TiO2 sintered on an fluorine-doped tin oxide(FTO) substrate. The counter electrode is a platinized FTO glass. The electrolyte, using I3-/I- (LiI and I2) in the solution of acetonitrile with a hint of water as the redox shuttle, is injected into the gap between the photoelectrode and the counter electrode to fabricate the cell. The microstructure and morphology of the TiO2 and CPCN materials are characterized by field emission scanning electron microscopy(FESEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), Fourier infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS) and nuclear magnetic resonance spectroscopy(NMR). The photoelectric and electrochemical properties of the TiO2, the CPCN as well as the TiO2/CPCN photoelectrodes are investigated using ultraviolet photoelectron spectroscopy(UPS), UV-Vis absorption spectrum, cyclic voltammetry(CV), galvanostatic charge- discharge(GCD) and electrochemical impedance spectroscopy(EIS).

    Effect of Guest Isomerism on Afterglow Color of Organic Host-guest Crystals
    MAO Jiayi, FENG Wenhui, WANG Tianyang
    2023, 44(6):  20220771.  doi:10.7503/cjcu20220771
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    High-performance organic long-persistent luminescence materials(OLPLMs) have potential applications in information storage, anti-counterfeiting, photodynamic therapy, etc. However, due to the limitation of the energy gap law, there are few studies on preparation of red afterglow materials. Herein, two kinds of host-guest doped-crystals 2MBP∶BA and 2MBP∶BPT were constructed by mixing the two isomers of benzanthracene(BA) and triphenylene(BPT) into the molten host material 4,4′- dimethylbenzophenone(2MBP) through magnetic stirring, respectively. Taking advantage of the difference of both doped-crystals in Förster energy transfer between the host and guest, the distinct afterglow colors were exhibited. By changing the structure of the guest molecule, the transition from green afterglow to red afterglow was realized, and a deep red afterglow(2MBP∶BA) lasting for 2 s was obtained. Moreover, utilizing the difference of afterglow color, a novel two-color microarray based on ASCII binary code was constructed for information encryption, reflecting the unique performance advantages of this kind of OLPLMs.

    Preparation and Catalytic Behavior in Ethylene Oligomerization of Nickel Catalyst Supported by Dendritic PAMAM Functionalized Nano-silica
    HUANG Jin, GUO Lijun, LI Feng, LI Yang, LI Cuiqin
    2023, 44(6):  20220778.  doi:10.7503/cjcu20220778
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    Nano-silica supported nickel catalyst(compound G) with good catalytic activity and reusability was prepared through anchoring via covalent binding of dendritic poly(amido amine)(PAMAM) in nano-silica. The composition and the morphology of compound G were verified by elemental analysis, Fourier transform infrared spectrophotometer(FTIR), inductively coupled plasma(ICP), X-ray diffraction(XRD) and scanning electron microscopy(SEM). The catalytic behavior of compound G in ethylene oligomerization was evaluated and the effect of oligomerization parameters on the catalytic properties of compound G was investigated. The results showed that compound G had good catalytic properties and repeatability. Based on the grey correlation analysis, it was found that the reaction pressure was the most important factor affecting the activity of ethylene oligomerization, and the reaction temperature was the most important factor affecting the selectivity of ethylene oligomerization. When the methylaluminoxane(MAO) was cocatalyst, the dosage of compound G was 5 μmol, the molar ratio of Al/Ni was 500, reaction pressure was 0.7 MPa, reaction time was 30 min and reaction temperature was 35 ℃, the catalytic activity was 3.85×105 g/(mol Ni·h) and the selectivity of C4—C8 olefins was 94.98%. The nickel content, the catalytic activity and the selectivity of C8 olefin for compound G were higher than nickel catalyst supported by amino modified nano-silica (compound E) due to dendritic effect. And the catalytic activity of compound G was 3.12×105 g/(mol Ni·h) and the selectivity of C8 olefin was 36.37% after the third oligomerization reaction.

    (Ag, Au)/MoS2 as Electrocatalyst for Water Splitting and Its Thermoplamonics Effect
    SANG Lixia, MA Mengnan
    2023, 44(6):  20220768.  doi:10.7503/cjcu20220768
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    MoS2 has expected to become a promising non-precious metal catalyst for hydrogen evolution from water electrolysis, and its performances need to be improved by optimizing its active sites. In this paper, two-dimensional flake MoS2 was synthesized on three-dimensional conductive carbon cloth(CC) by hydrothermal method. When adjusting the reaction temperature from 200 ℃ to 180 ℃, 1T phase with more active sites of MoS2 can be reserved, and the corresponding MoS2(180)/CC electrode exhibits a relatively lower hydrogen evolution overpotential. Ag/MoS2(180)/CC and Au/MoS2(180)/CC were prepared by deposing Ag and Au nanoparticles on MoS2(180)/CC via electrochemical process, respectively. Based on characterization of scanning electron microscopy(SEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and measurements of polarization curves, electrochemical impedance spectroscopy(EIS) and Tafel slope of the resultant electrodes with and without illustration as well as heating, it can be found that the overpotentials and current densities of Ag/MoS2(180)/CC and Au/MoS2(180)/CC can be improved due to the deposition of 20 nm Ag and 30 nm Au or the condition of irradiation, and the role of temperature rise is related to the type of metal. Furthermore, MoS2, Ag/MoS2 and Au/MoS2 models were constructed by using the COMSOL Multiphysics software, and the electric field and temperature field under illumination were simulated and calculated, confirming thermoplamonics effect of Ag and Au nanoparticles and its role in accelerating the kinetics of the electrode reaction and improving the hydrogen evolution performance of electrolyzed water.

    Polymer Chemistry
    Rapid Grafting of Phenylboronic Acid with Hydroxypropyl Chitosan Mediated by HATU
    LI Aoqi, HU Chuanzhi, SHI Han, DENG Mingyu, XIAO Bo, JIANG Bo
    2023, 44(6):  20220698.  doi:10.7503/cjcu20220698
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    Phenylboronic acid(PBA) can form reversible covalent bonds with cis-1,2-diol or 1,3-diol in an aqueous solution, which makes it useful as the glucose-responsive units or dynamic cross-linking groups in nano/hydrogels. In this paper, PBA was efficiently grafted on hydroxypropyl chitosan(HPCS) by employing 2-(7-azabenzotriazol-1-yl)- NNN',N'-tetramethyluronium hexafluorophosphate(HATU) as a coupling reagent in dimethyl sulfoxide(DMSO). The resulting carboxyphenylboronic acid-grafted hydroxypropyl chitosan(CPBA-HPCS) was soluble when pH>8.5, and the structure was characterized and confirmed by Fourier-transform infrared spectroscopy(FTIR) and nuclear magnetic resonance(NMR). In addition, the kinetics of the reaction were studied and a series of CPBA-HPCS with different substitution degrees(up to 0.78) was prepared. This novel chitosan derivative has good application prospects in the preparation of smart hydrogels and drug carriers.

    Preparation and Performance of Turing Structured Polybenzimidazole Solvent-resistant Nanofiltration Membrane
    SHANG Erhui, CHEN Huiling, HE Miaomiao, ZHOU Xinlai, CHEN Dongju
    2023, 44(6):  20220705.  doi:10.7503/cjcu20220705
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    Polybenzimidazole(PBI) was used as raw material to prepare nanofiltration membrane with turing structure by coordination induced phase inversion method in this paper. The morphology of turing membrane was controlled by changing the content of polymer. The nanofiltration performance of turing membrane was investigated and the stability of turing membrane in organic solvents was tested. The surface morphology and structure of the prepared Turing films were characterized by optical microscopy(OM), scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR). For the first time, the Turing membrane prepared by coordination induced phase inversion method was used in solvent resistant nanofiltration. The results showed that the turing membrane exhibited excellent nanofiltration performance and good solvent resistance. The rejection of rose red(RB), bromothymol blue(BTB) and methylene blue(MB) could reach more than 99%. In the strong polar solvent NN- dimethylformamide(DMF), when the filtration time was up to 40 h, the retention rate of RB was still above 86.66%, showing a good application prospect in solvent resistant nanofiltration.