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Table of Content

    10 February 2019, Volume 40 Issue 2
    Content
    Cover and Content of Chemical Journal of Chinese Universities Vol.40 No.2(2019)
    2019, 40(2):  0-0. 
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    Inorganic Chemistry
    Fabrication of Silica and Titania Anti-coking Passivation Layers in High Aspect-ratio Tubular Reactors by Atomic Layer Deposition
    HUI Longfei,LI Jianguo,GONG Ting,SUN Daoan,LÜ Jian,HU Shenlin,FENG Hao
    2019, 40(2):  201-209.  doi:10.7503/cjcu20180374
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    Silica and titania thin films were deposited inside the micro channels of stainless steel tubular reactors by atomic layer deposition(ALD) to suppress the metal catalyzed coke formation during thermal cracking of hydrocarbon fuels. Quartz crystal microbalance measurements reveal that the average film growth rate is 0.15 nm/cycle for silica and 0.11 nm/cycle for titania. The thicknesses of the passivation layers can be precisely controlled by changing the number of ALD cycle. In coking experiments, very thin films of silica or titania only show modest anti-coking performances and thicker coatings can effectively enhance the run lengths of the micro channel reactors. Generally, ALD titainia coatings perform better than silica coatings. The best anti-coking performance is obtained with a 1000-cycles ALD titania passivation layer, which can extend the lifetime of the reaction system by a factor of 4 to 5.

    Preparation of Yolk-shell Fe3O4@SiO2@PMO Magnetic Microspheres for Laccase Immobilization
    DUAN Bingyi,WANG Yu,GUO Ningning,WANG Runwei,ZHANG Zongtao,QIU Shilun
    2019, 40(2):  210-215.  doi:10.7503/cjcu20180517
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    Yolk-shell Fe3O4@SiO2@PMO magnetic microspheres were prepared and used to immobilize laccase using glutaraldehyde as the crosslinking agent. The influence of some experimental factors, such as glutaraldehyde concentration, crosslinking time and immobilization time, on laccase immobilization were investigated. The largest immobilization amount of laccase in the Fe3O4@SiO2@PMO microspheres is 475 mg/g. After immobilization, the laccase could survive in harsh environment, showing relative enzyme activities of 70% and 65% at pH=2.5—4.5 and 60 ℃, respectively. This means immobilization on Fe3O4@SiO2@PMO could afford higher stability than bare laccase. Besides, immobilized laccase could be recycled easily via simply magnetic separation, with activity retention of 85% even after 10 times recycle.

    Boron Nitride Nanotube-nanosheet Hierarchical Structures andIts Optical/adsorption Properties
    JI Yuchun,MAO Wenhui,LIAO Hejie,WANG Jilin,LONG Fei,GU Yunle
    2019, 40(2):  216-223.  doi:10.7503/cjcu20180429
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    Ammonium pentaborate, ammonia borane and magnesium oxide powder were ball milled and then heated at 1200 ℃ for 12 min in the atmosphere of 50 mL/min ammonia gas. And the white flocculent product was collected on the surface of the alumina substrate. The experimental results indicated that the samples revealed one-dimensional linear hierarchical structures with an average length of more than 5 mm and the outsider diameter of 200—800 nm. And the middle of the hierarchical structure was bamboo-like hollow structure with the inner diameter of 50—350 nm. In addition, abundant BN nanosheets loaded on the surface of the BNNT hierarchical structure and the thickness of single nanosheet was about 13 nm. Lots of nanosheets bended, folded and interweave together to form BN layer with the thickness of 50—200 nm. Besides, UV-Vis and PL analysis demonstrated that the as-synthesized BNNT hierarchical structures could be used in the field of ultraviolet light materials. The BNNT hierarchical structures also presented excellent adsorption property for methylene blue(MB). When the adsorption time was 7 min, MB was removed by 71% from water solution. The adsorption rate increased to 96% when the adsorption time was 107 min. Finally, the comparison experiment indicated that the growth mechanism of BNNT followed the vapour-liquid-solid(VLS) model, but the growth mechanism of the surface-loaded BN nanosheet belonged to vapour-solid(VS) model.

    Comprehensive Utilization of Rice Husk to Prepare Xylose, Capacitance Carbon and Calcium Silicate Whiskers
    SUI Guanghui,CHENG Yanyan,CHEN Zhimin,WEI Qingling,WANG Xiaofeng,YANG Xiaomin,WANG Zichen
    2019, 40(2):  224-229.  doi:10.7503/cjcu20180424
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    Hemicellulose of rice husk was used to prepare xylose by acid catalytic hydrolysis. The xylose cinder was carbonized and separated into C and Si. C was activated into capacitance carbon by activated modification, and Si was used to synthesize calcium silicate whiskers by hydrothermal method. Thus, all the components of rice husk were utilized comprehensively. The electrochemical performance of the capacitance carbon was studied by cyclic voltammeter(CV) and galvanostatic charge-discharge(GCD) tests. The structure and morphology of the calcium silicate whiskers were studied by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The results show that the xylose yields(Y1/Y2/Y3) and contents(mass fraction, C1/C2/C3) of the first, the second and the third hydrolysis can achieve Y1=98.5%, C1=3.6%, Y2=85.4%, C2=6.3% and Y3=76.6%, C3=9.0% under the optimized conditions, which are 7%(mass fraction) sulfuric acid, 1:8 solid-to-liquid ratio(g/mL), 2.0 h reaction time. The capacitance carbon prepared by activated modification with 15 mL 8% NaOH solution(AC/15) has the specific capacitance of 77.32 F/g, and a better double rate and cyclic stability.

    Analytical Chemistry
    Construction of Cyclodextrin Polymeric Membrane Sensor Based on Graphene and Potential Recognition for Histidine Enantiomer
    WU Yan,LIAN Huiting,SUN Xiangying,LIU Bin
    2019, 40(2):  230-239.  doi:10.7503/cjcu20180562
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    Cyclodextrin polymer with chiral recognition function were selected as chiral selectors, and graphene materials with excellent performance were used to further amplify the difference in peak potential response, cyclodextrin polymeric membrane sensor based on graphene was constructed by layer modification. There was a significant difference in the peak potential response between two components of histidine enantiomer. The potential difference is nearly 100 mV. A good linear relationship was showed between the oxidation peak potential and enantiomeric excess of the mixed solution. The mixed solution consists of different ratios of two components histidine enantiomer. A new method for simultaneously identifying two components of histidine enantiomer by potential response can be established.

    Uric Acid Biosensor Based on Ni Wire Modified with NiO Nanosheets
    JIA Hongliang,ZHAO Jianwei,QIN Lirong,ZHAO Min
    2019, 40(2):  240-245.  doi:10.7503/cjcu20180519
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    Ni wire modified with NiO nanosheets was synthesized by hydro-thermal method accompanied with heat treatment at high-temperature. The characterized results revealed that these NiO nanosheets grew uniformly on the surface of the Ni wire, with a size of several hundreds of nanometers and a thickness of about ten nanometers. Electrochemical experiments showed that the Ni wire modified with NiO nanosheets could be used as a kind of good material for immobilization of uricase to fabricate an efficient uric acid biosensor. Sensitivity of the prepared biosensor was found to be 821.4 μA/(mmol·cm2). The linear range for the detection was 1—900 μmol/L. The detection limit was 0.1 μmol/L. These results indicate that the Ni wire modified with NiO nanosheets is a new platform for the construction of biosensors.

    Discrimination of Ginseng Origins and Identification of Ginsenoside Markers Based on HPLC-MS Combined with Multivariate Statistical Analysis
    ZHAO Huanxi,WANG Qiuying,SUN Xiuli,LI Xue,MIAO Rui,WU Dongxue,LIU Shuying,XIU Yang
    2019, 40(2):  246-253.  doi:10.7503/cjcu20180452
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    High performance liquid chromatography-mass spectrometry combined with multi-variate statistical analysis was employed to discriminate 45 ginseng samples harvested from 5 different main cultivation areas in Northeast China and to identify the differential ginsenoside markers. A total of 41 ginsenosides, which included 15 protopanaxatriol type, 24 protopanaxadiol type and 2 oleanolic type ginsenosides, were identified based on the elution order of total ginsenosides in the reverse-phase C18 column coupled with the tandem MS analysis and comparison with authentic standard. Multivariate statistical analysis was further used to extract the information of HPLC-MS data sets. Orthogonal partial least squares-discriminate analysis revealed that the established analysis model had high goodness of fit and predictability. All the 45 ginseng samples were discriminated according to their origins. And 18 ginsenosides were identified as the differential markers, which contri-buted most to the simultaneous discrimination of the 5 ginseng origins. In addition, the differential ginsenoside markers which could distinguish any two origins were mainly those of high content in wild ginseng, such as Rb1, Rg1, Re, Rc, Rd, Ro, and m-Rb1. In the results of hierarchical clustering analysis, the ginseng samples of Heilongjiang and Jilin Province gathered separately except for the samples from Suihua city, which showed similarity to those of Jilin Province. This discrepancy may be attributed to the geographical location. Suihua city is relatively closer to Jilin Province and hence results in the similar growth environment of ginseng and the facility to exchange germplasm resources.

    Organic Chemistry
    Synthesis and Antitumor Activity of N9 Position Aromatic Substituted Purine-8-one Derivatives
    LÜ Mingjun,LI Wen,YANG Xinying,FANG Hao
    2019, 40(2):  254-261.  doi:10.7503/cjcu20180573
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    A series of novel N9 position aromatic substituted purine-8-one derivatives was synthesized and the antitumor activities were evaluated in vitro. Chemical structures of target compounds were confirmed by means of nuclear magnetic resonance(NMR) and high resolution mass spectroscopy(HRMS). The antiproliferative acti-vities of target compounds were tested on a panel of tumor cell lines using thiazolyl blue tetrazolium bromide(MTT) assay. The results revealed that the substitutions on C2 and N9 position had great impacts on antitumor activities. Moreover, introducing aniline attached six-member ring on C2 position or p-CF3 on N9 position could improve the antitumor activities. Importantly, the most potent compound 12c exhibited better inhibitory activities than R-Roscovitine against four tumor cell lines, including human leukemia cell lines(K562), human prostatic carcinoma cell lines(PC-3), human breast cancer cell lines(MDA-MB-231) and human colon cancer cell lines(HCT116).

    Synthesis of Novel Polyheterocyclic Molecules with 1,3,4-Oxadiazole Thioetheramide as Core Framework and Their Inhibitory Activity on Cdc25B and PTP1B
    ZHANG Chenglu,GONG Rongqing,YANG Jingyi,SUN Xiaona,LI Yilin,WANG Huayu,SONG Fulu,SUN Yuedong
    2019, 40(2):  262-271.  doi:10.7503/cjcu20180525
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    1,3,4-Oxadiazole derivatives(5) were constructed using aromatic hydrazide containing a triazines(3). Then, compound 5 was combined with the derivatives 6 containing 1,3,4-thiadiazole to synthesize eighteen target molecules. Their structures were characterized by infrared spectroscopy(IR), nuclear magnetic resonance(NMR) and high resolution mass spectrometry(HRMS). The inhibitory activities of the target molecules against cell division cycle 25B(Cdc25B) and protein tyrosine phosphatase 1B(PTP1B) were evaluated. The results showed that eight target molecules had better inhibitory activities than their positive reference and could be expected to be potential Cdc25B inhibitors; twelve target molecules had better inhibitory activities than their reference and could be expected to be potential PTP1B inhibitors.

    Antifungal Activity and Mechanism of an Essential Oil from Eremothecium ashbyii
    HE Feng,BAI Jinhai,CHEN Shuxian,TAN Xiaobei
    2019, 40(2):  272-279.  doi:10.7503/cjcu20180477
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    The essential oil was obtained from the broth of Eremothecium ashbyii H4565 by solvent extraction and steam distillation. The chemical components of essential oil were investigated by gas chromatography-mass(GC-MS) spectrometry. Antifungal activities were studied by inhibition zone method. Two fold dilution method was used to determine the minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC). Cytoplasmic membrane permeability, protein and potassium ion leakage, and transmission electron microscope were used to determine antifungal mechanism. The results showed that the yield of essential oil was 0.54 g/L. Twenty two compounds, about 98.82% constituents of the total, were identified by GC-MS analysis. The essential oil was composed mainly of monoterpenes, sesquiterpenes, aromatic alcohol, and sesquiterpene hydrocarbons. The essential oil exhibited strong antibacterial activities against C. albicans, C. guilliermondii, C. tropicalis, C. glabrata, C. neoformans and S. cerevisiae. The MIC of the essential oil against these microorganisms were 31.25, 31.25, 62.5, 31.25, 15.625 and 15.625 μg/mL, respectively. The MBC of the essential oil against these microorganisms were 62.5, 62.5, 125.0, 62.5, 31.25 and 31.25 μg/mL, respectively. Based on analyses of cytoplasmic membrane permeability, protein and potassium ion leakage and transmission electron microscope, the possible targets of the essential oil were cell wall and cytoplasmic membrane. The results showed a new light on development and application of the essential oil from microorganism.

    Physical Chemistry
    Theoretical Study on Enhancement Effect of Amino Modification of Adenine on Conductivity of DNA
    CHENG Yingying,LIU Haiying,TIAN Yigeng,LIU Zhongqi,LI Qingxin
    2019, 40(2):  279-287.  doi:10.7503/cjcu20180673
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    The effect of amino modification of adenine(A) on DNA conductivity was studied by density functional theory combined with non-equilibrium Green’s function. The results show that the formed diaminopurine(D) could pair with thymine(T) through three hydrogen bonds. Owing to the new formed hydrogen bond by amino modification, the binding between the paired bases D and T was tighter than that in AT. Energy gaps and ionization energies of the modified systems were greatly decreased. And the UV absorption spectra are red shifted with more charge-transfer transitions for DT. Properties of the transverse charge transport along hydrogen bonds and the longitudinal charge transport along DNA strand directly demonstrated that replacing A with D could largely increase the conductivity of DNA. More importantly, the mechanism of enhancement effect was indicated. The amino modification adjusted the HOMO(highest occupied molecular orbital) level of DT base pair closer to that of GC compared with AT, thus reducing the energy barrier of hole migration in DNA. This may shed some light on the design of novel DNA-based molecular devices.

    Development of Polarization Force Field for Guanine and Amino Acid Residues Systems
    XU Yan,LIU Cui,HAN Chengjuan,PAN Mingyu,SUN Zhaoqi,HAN Bingyu,YANG Zhongzhi
    2019, 40(2):  288-297.  doi:10.7503/cjcu20180653
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    The recognition of DNA depends mainly on the hydrogen bonding between corresponding residues of the enzyme and base. Hydrogen bonding is important for maintaining the stability of DNA and protein structures. In order to more realistically simulate biomolecules, a polarization force field(PFF) has been proposed. The main difference between the different force fields is the handling of electrostatic interactions. A fluctuating charge force field was developed and applied to guanine G and amino acid residue systems. In order to accurately describe the hydrogen bond, the force field clearly defines the charge and position of the lone pair of electrons and bonds. The polarization effect was reflected by the floating of the charge with the environment. The position of the lone pair of electrons has a good control of the angle of hydrogen bonds. The hydrogen bond energy was depicted by the hydrogen bond fitting function kHB. The quantum chemical method was used to calculate and analyze the G and amino acid residue systems from hydrogen bond, geometry and charge distribution. Based on this, the parameter was confirmed and applied to the hydrogen bond system of G and amino acid residues. Three different force fields were used to simulate the structure and property of target molecules. The simulation results show that the developed ABEEMσπ PFF has the best consistency with the quantum chemical method.

    Study on the Mechanism of Charge Tunneling and Hopping Transport in Ferrocene Self-Assembled Molecular Junctions
    HAN Bin,YU Xi,HU Wenping
    2019, 40(2):  298-305.  doi:10.7503/cjcu20180629
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    The charge transport properties of non-electroactive 1-undecanethiol(C11) and electroactive 6-(ferrocenyl) hexanethiol(FHT) molecular junctions using thiol self-assembled monolayer combined with suspended nanowires technology were compared and studied. Combining the two transmission mechanisms, a new model was proposed to fit the current-voltage characteristics of the molecular junction. It is found that the FHT of redox active center molecule can change the charge transport from tunneling to tunneling-hopping coexistence mechanism. This mechanism was verified in combination with variable temperature experiment, and the possible reasons for this mixing process was explained.

    Preparation and CO2 Reduction Performance of Composite Photocatalyst Based on Aminated Coal-based Carbon Dots
    ABUDUHEIREMU Awati,ZHANG Dedong,HALIDAN Maimaiti
    2019, 40(2):  306-316.  doi:10.7503/cjcu20180597
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    The crystalline carbon in the coal structure[coal-based carbon dots(CDs)] was stripped by hydrogen peroxide oxidation method, and then the surface of the synthesized carbon dots was modified by thionyl chloride chlorination, ethylenediamine passivation steps to obtain N, S co-doped aminated coal-based carbon dots(NH2-CDs). After that, using the coordination and dispersing function of amino groups and oxygen-containing functional groups on the surface, a kind of composite photocatalyst, Cu2O/NH2-CDs, was prepared by coating cuprous oxide(Cu2O) nanoparticles, which were obtained by in situ reduction of copper chloride(CuCl2∙2H2O), on the NH2-CDs. The structures of the Cu2O/NH2-CDs were characterized and the photocatalytic performance toward CO2 reduction under visible light was tested. The results show that the presence of NH2-CDs not only makes the composite catalyst possess excellent CO2 adsorption performance, but also improve the efficient electron-hole pair separation and electron transfer ability of the composite catalysts, so that Cu2O/NH2-CDs show excellent CO2 photocatalytic reduction to HCOOH performance. After reaction for 6 h, the amount of HCOOH was up to 2582.4 μmol/g cat, about 7.3 times of that on Cu2O photocatalyst under the same conditions.

    Molecular Simulation Study on Influence and Screening of Micro-porous Materials for Phosgene Adsorption and Diffusion
    CHEN Xiaofeng,NING Hejia,YANG Li,PENG Changjun,SUN Wei
    2019, 40(2):  317-325.  doi:10.7503/cjcu20180575
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    The adsorption and diffusion of phosgene(COCl2) were calculated using molecular simulation in micro-porous materials. The influence of geometry of materials was still analyzed. The results show that the adsorption isotherms mainly are type Ⅰ and type Ⅴ in the researches. At low pressure the good performance of adsorption is covalent organic framework(COF) series and metal-organic framework(MOF) containing open-metal sites. Through the comparison of adsorption in different pressures, the adsorption capacity was determined by void fraction(VF) of materials with pressure increasing before reaching saturated adsorption. The strong adsorption site could obstruct the diffusivity of phosgene in micro-porous materials from molecular dynamic simulation. The diffusivity of phosgene is affected by competition between molecular synergy effects and steric effects through the analysis of radial distribution function(RDF) and molecular trajectory. It was found that COF-102, COF-300, ZnMOF-74, Zn-DOBDC and PCN-60 are good candidates for phosgene adsorption, which would be implemented in environment governance for capture of phosgene.

    Effects of Sn Loading on Catalytic Performance of PtSn/Al2O3 in Propane Dehydrogenation
    MA Zhanhua,LI Shuai,JIANG Aijing,LI Jun,SUN Lanyi,WEI Guijuan,AN Changhua
    2019, 40(2):  326-333.  doi:10.7503/cjcu20180545
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    PtSn/Al2O3 catalysts with different Pt/Sn molar ratios(3:1, 1:1, 1:2 and 1:3) were prepared by carbonylation-impregnation method. The catalysts were characterized by means of nitrogen adsorption-desorption, X-ray diffraction(XRD), transmission electron microscopy(TEM), infrared spectra of pyridine adsorption(Py-IR), and thermogravimetric-differential thermal analysis(TG-DTA). The effect of Sn loading on the catalytic properties of PtSn/Al2O3 in the propane dehydrogenation was studied. The results showed that the PtSn/Al2O3 catalyst had high propylene selectivity and catalytic stability. Platinum and tin were mainly in the form of Pt3Sn and PtSn alloys with Pt/Sn ratios of 3:1 and 1:1. With the formation of the alloy, the dehydrogenation performance of the catalyst was improved significantly, and the high temperature sintering of metal particles was effectively suppressed. When the Pt/Sn ratio was 1:2 and 1:3, the metallic Pt was mainly resulted. With the increase of Sn loading, the Lewis acid sites on the catalyst gradually decreased, and the propylene selectivity increased associated with the propane conversion decreased. At the same time, the addition of Sn promoted the migration of carbon deposition from the metal surface to support, and improved the stability of the catalyst.

    Formaldehyde Ethynylation Reaction over Cu2O Supported on TiO2 with Different Phases
    WANG Zhipeng,NIU Zhuzhu,BAN Lijun,HAO Quanai,ZHANG Hongxi,LI Haitao,ZHAO Yongxiang
    2019, 40(2):  334-341.  doi:10.7503/cjcu20180523
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    Cu2O/TiO2 catalysts with anatase and rutile titania as supports were prepared by liquid reduction-deposition-precipitation method and applied in 1,4-butynediol synthesis by formaldehyde ethynylation reaction. Effects of different TiO2 polymorphs on structure and catalytic performance of catalyst were investigated, combined with N2 physical adsorption-desorption, H2-temperature programmed reduction(H2-TPR), high resolution transmission electron microscopy(HRTEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and CO infrared spectroscopy(CO-IR). The results showed that the ethynylation activity of catalyst with rutile TiO2 as support was obviously higher than that of anatase TiO2 as support. This was mainly due to the different surface structures originated from the different crystalline structures of the as-prepared TiO2.The(110) planes were preferentially exposed planes for rutile TiO2. Compared with anatase TiO2, the higher density vacant sites and different coordination structures of copper species on rutile (110) planes facilitated the formation of more Cu—O—Ti structures, exhibiting stronger interaction between Cu2O and the support. Meanwhile, the stronger interaction between Cu2O and rutile efficiently retained the dispersion of active species and stablized the valence of Cu+, leading to a higher catalytic performance.

    Effects of Annealing Atmosphere on Composition, Structure and Photovoltaic Properties of Solution-processed Sb2S3 Thin Films
    QI Juanjuan,DONG Chao,Getinet Y. Ashebir,CHEN Junwei,WAN Zhiyang,CHEN Wangwei,ZHAO Qiuyuan,WANG Mingtai
    2019, 40(2):  342-349.  doi:10.7503/cjcu20180482
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    Chemical bath deposition(CBD) method was used to deposit Sb2S3 on condensed TiO2 film to prepare TiO2/Sb2S3 planar heterojunction, and the FTO/TiO2/Sb2S3/PCPDTBT/MoO3/Au planar devices were fabricated with poly[2,6-{4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene}-alt-4,7-(2,1,3-benzothiadiazole)](PCPDTBT) hole transporting layer and MoO3 interfacial layer to modify Au electrode. The effects of annealing atmospheres on the composition, structure and photovoltaic properties of solution-processed Sb2S3 thin films were investigated. The results show that the cell efficiency only reaches 0.90% when the TiO2/Sb2S3 film is annealed in N2 atmosphere due to the presence of Sb2O3 secondary phase and a poor compactness in the resulting Sb2S3 thin film, while the smooth, well condensed and pure Sb2S3 thin film is obtained when annealing the TiO2/Sb2S3 film in N2-S atmosphere, leading to the elimination of Sb2O3 secondary phase and a significant increase in efficiency by 1.34 folds to 2.04%. It is found that the removal of Sb2O3 impurity reduces the charge recombination and facilitates the transport and collection efficiency of both electron and holes in bulk Sb2S3 layer, leading to improved device performance.

    Sulfur Tolerance of the CeTiOx Catalysts for Selective Catalytic Reduction of NO with NH3
    ZHU Hongtai,SONG Liyun,HE Hong,YIN Mengqi,CHENG Jie,SUN Yanming,LI Shining,QIU Wenge
    2019, 40(2):  350-357.  doi:10.7503/cjcu20180241
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    Ceria-based catalysts(CeTiOx-A and CeTiOx-B) were prepared by solid state ball milling method with Ce2(C2O4)3 and Ce(SO4)2 as precursors, respectively. Then, the prepared ceria-based catalysts were treated in reaction atmosphere consisted of 0.15%SO2 for 40 and 60 h, respectively. The obtained catalysts were designated as 40CeTiOx-A, 60CeTiOx-A, 40CeTiOx-B and 60CeTiOx-B. The performances of fresh and used catalysts for selective catalytic reduction(SCR) of NO with NH3 as the reductant were investigated. The catalysts were also characterized using X-ray diffraction(XRD), X-ray fluorescence spectra(XRF), Brunner emmet teller(BET), H2-temperature programmed reduction(H2-TPR), X-ray photoelectron spectra(XPS), NH3-temperature programmed desorption(NH3-TPD) and SO2-temperature programmed desorption(SO2-TPD) techniques. The results indicated that the NH3-SCR activity, SO2 and H2O resistance over the CeTiOx-A catalysts were better than over the CeTiOx-B samples. The reasons for this phenomenon are that CeTiOx-A catalysts possess larger specific surface area and pore volume than CeTiOx-B catalysts. Besides, CeTiOx-A catalysts have plenty of Ce3+ and the surface adsorbed oxygen, which would benefit the adsorption and activation of NO. Furthermore, CeTiOx-A catalysts also have numerous strong Lewis acid sites, which lead to the increasing adsorption of NH3. Therefore, the NH3-SCR reaction rate and the NO conversion of CeTiOx-A catalysts was improved.

    Polymer Chemistry
    Preparation of Photo-responsive Film by Electrochemical Deposition Method and the Application in Optical Information Storage
    ZHAO Ruiyang,YU Chunyan,HAN Jishu,FU Yunlei,LI Ming,HU Dehua,LIU Fusheng
    2019, 40(2):  358-365.  doi:10.7503/cjcu20180533
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    In order to improve the stability of photo-isomerization patterning of photo-responsive film based on azobenzene moiety, a new photo-responsive material based on azobenzene moiety with high electrochemical activity was designed and synthesized, named 1,2-bis(4-{[6-(9H-carbazol-9-yl)hexyl]oxy}phenyl)diazene(BHCzAzo) which exhibited a good photo-isomerization ability between trans-configuration and cis-configuration. BHCzAzo was prepared into a highly crosslinked polymer film without any crack or peeling on the surface using electrochemical deposition(ED) method due to the electrochemical activity of carbazole moiety in BHCzAzo. And the stability of the prepared film was enhanced in the result of the compact stacking mode of ED film. The film was irradiated with 355 nm interfering laser beam, and then a periodic pattern of photo-induced surface relief gratings was formed with good morphological surface. The photo-induced pattern was proved to possess high stability using the experiments of being immersed in different common solvent and heated at different temperature. The stability of photo-induced pattern was greatly enhanced by preparing cross-linked film with photo-responsive ability using ED method.

    Reversible-deactivation Radical Solution Polymerization of Methyl Methacrylate Catalyzed by Tetrabutylammonium Iodide
    ZHANG Xiaotao,WANG Yan’an,HUI Jia,SHI Yan,FU Zhifeng,YANG Wantai
    2019, 40(2):  366-371.  doi:10.7503/cjcu20180526
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    Tetrabutylammonium iodide(BNI) has been found to be a highly efficient organic catalyst for the reversible-deactivation radical polymerization(RDRP) of methyl methacrylate with an in situ formed alkyl iodine initiator. The polymerization results exhibited typical features of “living”/controlled radical polymerization. The polymerization process efficiently controls the molecular weight and chemical structure of the poly(methyl methacrylate)(PMMA). Furthermore, the inhibition period was shortened and the polymerization rate was increased upon the addition of BNI as compared to blank controls. The effect of BNI contents on the controllability of MMA polymerization was also investigated in detail. The results showed that good agreement between theoretical and experimental molar masses(characterized by GPC) was observed for the used molar ratio of I2 to BNI(1:2, 1:1, 1:0.5, 1:1 and 1:0). The molar ratio of n(MMA):n(I2):n(ABVN):n(BNI)=200:1:1.7:1 is an optimum formula affording polymers with predetermined molecular weight and low-polydispersity polymers(Mw/Mn<1.2) at relatively high polymerization rate. The polymerizations of MMA in different solvents were carried out. The polymerizations have good control effect in toluene and benzene(Mw/Mn<1.2). The molecular structure and the chain end fidelity of the obtained low-molecular-weight PMMA(Mn,GPC=3300, Mw/Mn=1.15) prepared by reversible complexation mediated polymerization(RCMP) were demonstrated by 1H NMR spectrum. The calculated Mn,NMR was in good agreement with Mn,th and the fraction of iodine chain end of the PMMA chains was up to 91.6%.

    Electrospinning Preparation and Photocatalytic Activity of H4SiW12O40/Ethylene Vinyl Alcohol Copolymer Nanofibrous Membrane
    ZHANG Xinmu,CUI Xiangxu,YAOMA Kangyue,LI Tingting,ZHANG Zhiming
    2019, 40(2):  372-378.  doi:10.7503/cjcu20180500
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    H4SiW12O40(SiW12)/ethylene vinyl alcohol(EVOH) copolymer composite nanofibrous membrane was prepared by electrospinning. Characterization with energy-dispersive X-ray spectroscopy(EDX) and Fourier transformation infrared spectroscopy(FTIR) indicated that SiW12 was loaded into the EVOH nanofibrous membrane and its Keggin structure remained intact. The as-prepared SiW12/EVOH composite nanofibrous membrane exhibited excellent photocatalytic activity in the degradation of methyl orange(MO) under xenon lamp irradiation. The degradation efficiency of MO reached 96.3% as the mass ratio of EVOH to SiW12 was 2:1, which may be attributed to the synergistic effect of EVOH and SiW12. More importantly, the composite nanofibrous membrane presented an excellent reusability. There was no significant decrease of photocatalytic activity of the catalyst after three cycles of reactions, which mainly because the hydrogen bonds between SiW12 and EVOH could enhance the stability of SiW12 in the membrane. In view of this, SiW12/EVOH composite nanofibrous membranes exhibited the potential for practical applications to eliminate organic dyes from wastewater.

    Antibacterial Superhydrophobic-oleophobic Coating Fabricated by Candle Soot
    XIE Chao,HONG Guohui,YANG Weiqiang,WANG Jiku,ZHAO Lina
    2019, 40(2):  379-384.  doi:10.7503/cjcu20180485
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    Superhydrophobic-oleophobic coating with excellent antibacterial property was fabricated by chemical vapor deposition(CVD) on the surfaces of candle soot with silicon dioxide(SiO2) and trichloro(1H,1H,2H,2H-perfluorooctyl) silane(TMEDA). Morphological analysis by scanning electron microscope(SEM) showed that the candle soot possessed porous network nanostructure. The wetting property results by water contact angle characterization showed SiO2 deposited coating exhibiting superhydrophilic-lipophilic property which can be attributed to synergistic action of porous network nanostructure and SiO2. When further deposited by TMEDA on the surfaces of SiO2 deposited coating, not only the porous network nanostructure of coating was leaved behind, but also the superhydrophilic-lipophilic property of coating was transformed into superhydrophobic-oleophobic property. Such prepared superhydrophobic-oleophobic coating possesses higher antibacterial property by weakening the adsorption of bacteria on the solid surface. The synergistic action of superhydrophobic-oleophobic property and porous network structure leads to the excellent antifouling property of superhydrophobic-oleophobic coating. The superhydrophobic-oleophobic coating made up of candle soot may provide one new simple and effective approach for antibacteria in industrial unit and public environment.

    Inflame-retardant Water-borne Epoxy Resin of APP Microsphere with Carrageenan Cladding
    WANG Na,YANG Fei,ZHANG Jing,FANG Qinghong
    2019, 40(2):  385-392.  doi:10.7503/cjcu20180416
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    After k-carrageenan was purified by barium chloride and degraded by hydrogen oxidation, a series of k-carrageenan/ammonium polyphosphate(k-CM/APP) inflame-retardant microsphere was prepared using inverse emulsion polymerization method. Then k-CM/APP was added to water-borne epoxy resin to prepare EP2, EP3, EP4 steel structure fire retardant coating. The structure and morphology of k-CM/APP were represented by using infrared spectrograph(IR), scanning electron microscope(SEM), energy dispersive spectrometry(EDS). The limit oxygen index(LOI), vertical combustion(UL-94), back temperature test method, thermogravimetry(TG), cone calorimeter, adhesion tester, IR and SEM were used for analyzing the flame retardant property, heat-insulating property, thermal property and mechanical property. Research results showed that k-CM/APP spherical structure was complete, and the carbon residue at 800 ℃ reached 59.5%. Compared with other fire retardant coatings, the LOI of the EP3 fire retardant coating with added k-CM/APP(3/1) reached 28.5%, UL-94 reached the class V-0, and the fire-resistant temperature of 60 min fire retardant coating was 253 ℃. Compared with pure EP coating, the heat release rate peak of EP2 coating was decreased by 58.26% and the total heat release quantity was decreased by 20.84%, adhesion reached 8.74 MPa.

    Biomimetic Mineralization at a Dilute Concentration and Application in Enantioseparation
    HE Yangyang,LI Yi,LI Baozong,YANG Yonggang
    2019, 40(2):  393-402.  doi:10.7503/cjcu20180394
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    The morphologies and pore architectures of silicas were controlled by tuning the pH value, aging time and the concentration of tetraethoxysilane(TEOS) using the self-assemblies of an L-phenylalanine derivative(L-18Phe6PyBr) at a concentration of 0.30 mmol/L. The obtained samples were characterized using field-emission scanning electron microscopy and transmission electron microscopy. The results indicated that left-handed twisted nanoribbons were obtained at pH=10.01, while straight nanoribbons were obtained at pH=7.15 and 12.34. The increasing of the aging time was beneficial to the formation of straight nanoribbons which should follow a dynamic templating approach. With increasing the mass ratio of TEOS/L-18Phe6PyBr from 2:1 to 15:1, the width of the twisted nanoribbons increased and the helical pitch became longer. Silica tubular nanoribbons were obtained after removing the organic template by calcination. Silica prepared from TEOS/L-18Phe6PyBr(2:1, mass ratio) was used as the stationary phase of the gas chromatography for enantioseparation. The results indicated that 1-phenyl-1-propanol, 1-(4-chlorophenyl)ethanol and 2-methylpentanoic acid enantiomers were able to be separated. Chiral supramolecular imprinting was proposed to drive this enantiosepartion ability of the silica. The results not only gave us a better understanding of the cooperation self-assembly behavior of the silica oligomer and the low-molecular-weight gelator, but also brought out a chiral inorganic stationary phase for enantioseparation.

    Preparation and Properties of Flexible Cross-linked Polyimide Aerogels
    LIU Tao,LI Wenjing,ZHANG Enshuang,ZHONG Jinyang,ZHANG Fan,LIU Yuanyuan,ZHAO Yingmin
    2019, 40(2):  403-409.  doi:10.7503/cjcu20180393
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    Polyimide aerogels were synthesized by sol-gel reaction, followed by supercritical drying. The effects of sol solid content and cross-linking agent ratio on performance of polyimide aerogels were investigated. The results showed that both the shrinkage and density of polyimide aerogels increased with increasing sol solid content and cross-linking agent ratio. With the increased sol solid content, the suitable thermal conductivity(0.026—0.033 W·m-1·K-1) declined at first and then increased, and the modulus and strength of polyimide aerogels was improved obviously. Introducing the cross-linking agent into molecular structure improved the toughness of polyimide aerogels, and the maximum value of break strain was 21.7%. The polyimide aerogels also showed high temperature stability. The good properties made them an ideal insulation for light weight and flexible thermal protection of advanced weapons and space vehicles.

    Preparation and Performance of the Self-crosslinking Sulfonated Poly(ether ether ketone) Proton Exchange Membrane
    CHEN Yuhan,HUANG Xuehong
    2019, 40(2):  410-418.  doi:10.7503/cjcu20180363
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    Side chain type, sulfonated poly(ether ether ketone)(SPEEK) was prepared via free radical addition reaction using PEEK containning 3,3'-diallyl bisphenol A structural unit and 3-mercaptopropane-sulphonate. The structure and morphology of SPEEK membrane were characterized by Fourier transform infrared spectroscopy(FTIR), 1H NMR, TGA and SEM. The SPEEK has high hydrophilic/hydrophobic phase separation. Water uptake, mechanical property, proton conductivity, VO2+ permeability and single cell performances were investigated in order to understand the relationship between morphology and property of the membranes. The vanadium ion VO2+ permeability through the SPFEK-4 membrane(IEC=2.12 mmol/g) is 1.54×10-6 cm2/min, which is lower than that of Nafion membrane(6.04×10-6 cm2/min). Tests of SPPEK-4 in vanadium redox batteries(VRB) demonstrate a comparable Columbic efficiency(CE) and energy efficiency(EE) to that of Nafion117 at 50 mA/cm2, and the SPPEK-4 membrane exhibits stable performance in cell over 50 charge-discharge cycles.