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10 July 2019, Volume 40 Issue 7

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Cover and Content of Chemical Journal of Chinese Universities Vol.40 No.7(2019)

2019, 40(7):  0-0. 

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Article: Inorganic Chemistry

Three-dimensional Covalent Organic Frameworks Synthesized by Room Temperature Ionic Liquid Method^†

LIU Xiaozhou, GUAN Xinyu, FANG Qianrong, JIN Yongri

2019, 40(7):  1341-1344.  doi:10.7503/cjcu20190086

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We report a new kind of three-dimensional(3D) covalent organic frameworks(COFs) synthesized by room temperature ionic liquid method, denoted as JUC-515, with a 5-fold interpenetrated diamond topological network. The main method to synthesize COFs is solvothermal method, which needs not only high temperature and high pressure but also long reaction time, making it hard to synthesize COFs, especially 3D COFs. Room temperature ionic liquid method, which uses room temperature and ordinary pressure as well as shorter reaction time, is easy to be carried out and can be regarded as a green chemistry method. JUC-515 has high crystallinity, large porosity and favorable carbon dioxide selectivity.



Design, Preparation and Surface-enhanced Raman Scattering(SERS) Spectrum of Single Ag Nanodot^†

FENG Wei,WANG Bowei,JIANG Yang,LI Longyun

2019, 40(7):  1345-1351.  doi:10.7503/cjcu20190032

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SERS substrate of single silver nanoclusters was prepared via a novel and simple method, and the surface-enhanced Raman spectra of single silver nanoparticles was studied. Also, the effects of plasma etching time and silver deposition thickness on the structure and morphology of single silver nanoclusters were investigated. And, the SERS spectra of pyridine, mercaptobenzene and R6G probe molecules were recorded on a single silver nanoparticle on PS arrays. In studying the SERS spectrum of R6G, the fluorescence quenching was carried out using the principle of fluorescence resonance energy transfer through PSS-TRITC. The SERS spectra and related calculations show that the Raman enhancement factor of a single silver nanoparticle can reach about 10⁶. The fabrication of metal nanocluster arrays by this method will have potential application prospects in the field of high sensitivity detection.



Photoluminescence Property of Layered Double Hydroxide Composite with Fluorescein and Detection Towards F{{\mathrm{e}}^{3+}}^{†}

LIANG Zupei, SU Feifei, GUO Rong, TANG Yuyao, JIN Shuo, YU Zihuan, LI Jian, MA Shulan

2019, 40(7):  1352-1358.  doi:10.7503/cjcu20180873

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FLN/OS-LDH composite(FLN is fluorescein, OS is 1-octane sulfonic acid sodium, and LDH is MgAl layered double hydroxide) was synthesized via ion-exchange method and the photoluminescence and detection for Fe(Ⅲ) was tested. In solid state, the FLN/OS-LDH composite displayed yellowish green emission(565 nm) arising from organic FLN. In formamide(FM), the FLN/OS-LDH can be feasily delaminated into colloidal suspention, and showed blue-shifted green emission(ca. 531 nm). The recognition ability of the FLN/OS-LDH for metal cations was researched. The delaminated FLN/OS-LDH colloid in formamide exhibited high selectivity for Fe³⁺ over other ions(Mg²⁺, Ni²⁺, Co²⁺, Cu²⁺, Zn²⁺, Mn²⁺, Pb²⁺, Cd²⁺, and Hg²⁺) with obvious fluorescence quenching, which can work as a kind of effective fluorescence sensor for detection of Fe³⁺. The detection limit of Fe³⁺ is determined to be 1.27×10^-7 mol/L and the quenching constant(K_sv) is 3.44×10² L/mol.



Controllable Synthesis and Catalytic Applications of Hydrophobic Hybrid Zeolites^†

LI Dan, WU Zhonghan, ZHOU Dan, JIANG Ding, LU Xinhuan, XIA Qinghua

2019, 40(7):  1359-1364.  doi:10.7503/cjcu20180560

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Ethyl/methyl-functionalized hybrid zeolites were synthesized using methyltriethoxysilane and ethyltriethoxysilane as organic silicon sources through rotating and static dry-gel conversion methods and characterized. The hydrophobicity of hybrid zeolites can be adjusted by synthetic routes, carbon chain length and gel composition, and hybrid zeolite with water contact angle of 124° were obtained. The catalyst prepared using hydrophobic hybrid zeolite as support showed excellent catalytic performance in the hydrogenation of phenol. It is ascribed to the aggregation of phenol molecules on the hydrophobic/lipophilic surface of catalyst that promotes the reaction efficiently.



Microfluidic Synthesis of UiO-66 Metal-organic Frameworks Modified with Different Functional Groups^†

SHENG Bingchen, LI Cong, LIU Yingya, WANG Anjie, WANG Yao, ZHANG Jian, LIU Weixu

2019, 40(7):  1365-1373.  doi:10.7503/cjcu20180831

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Zirconium based metal-organic framework UiO-66 was synthesized continuously by microfluidic method. Compared with the traditional solvothermal synthesis in batch reactors, microfluidic synthesis is more efficient. It has the advantages in highly efficient mixing and heat transfer, thus lead to enhanced reaction rates. Microfluidic synthesis can obtain uniform hexahedral crystalline products in nanometer range(less than 100 nm). The influences of temperature, total flowrate and residence time on the obtained products were investigated. Higher temperature benefited the growth of crystal. When flowrate increased, crystal sizes of UiO-66 synthesized by microfluidic method decreased. Crystal growth required sufficient residence time(20 min), but if the residence time was prolonged further, the crystal particle size would not change any more. By optimizing the synthetic parameters, UiO-66 modified with different functional groups, UiO-66-X(X=NH₂, NO₂, Br), could be synthesized continuously by microfluidic synthesis.



Analytical Chemistry

Synthesis of Meso-porous Co₃O₄ Polyhedra and Their Electrochemical Properties^†

ZHOU Hai, CHEN Hao, GUO Ya, KANG Min

2019, 40(7):  1374-1380.  doi:10.7503/cjcu20180853

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CoOOH polyhedra was synthesized via hydrothermal treatment of Co(NO₃)₂ and (NH₄)₂S₂O₈, which was then transformed into meso-porous Co₃O₄ polyhedra via thermal annealing. The structure and composition of materials were characterized by means of scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD) and N₂ adsorption-desorption. The influence of reaction time, reaction temperature and (NH₄)₂S₂O₈ concentration on the morphology of CoOOH polyhedra were investigated and the possible formation mechanism of CoOOH polyhedra was also analyzed. With respect to non-enzyme glucose sensing, the present Co₃O₄ polyhedra exhibited a linear detection range from 0.05 mmol/L to 1.8 mmol/L, a sensitivity of 148 μA·cm^-2·mmol·L^-1 and a detection limit of 1 μmol/L.



Preparation of ECB Molecularly Imprinted Film Fluorescent Sensor for Detection of Traditional Chinese Herbal Medicine^†

MA Yukun, WANG Haijun, GUO Mengyan

2019, 40(7):  1381-1389.  doi:10.7503/cjcu20180814

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Using Ebracteolata compound B(ECB) extracted from the root of Euphorbia Fischeriana steud as template molecule, 7-diethylamine coumarin-3-allyl terminal compounds(DCAC) synthesized by condensation reaction between 7-diethylamine coumarin-3-carboxylic acid and 3-bromopropene as fluorescent monomer, acrylamide as the functional monomer, ethylene glycol dimethacrylate as the crosslinking agent, azodiisobutyronitrile as the initiator, the molecularly imprinted fluorescent film sensor with strong cyan fluorescence was achieved through the free radical polymerization, which could selectively assemble ECB. The adsorption performance of the film showed that the linear range of ECB was 1.00—50.00 μmol/L. The cyan fluorescence(489 nm) quenching response of the film was shown obviously with the increasing concentration of ECB. The sensor could be used to detect the low concentration of ECB, with a detection limit to 0.29 μmol/L. The imprinting factor was 3.58, obviously higher than the analogues(2-methoxy-4-hydroxybenzoic acid, gallic acid and 3,3'-diacetyl-4,4'-dimethoxy-2,2',6,6'-tetrahydroxydiphenylmethane). The sensor with excellent reusability has been successfully applied to detect the content of ECB in Euphorbia fischeriana Steud.



Biotransformation of Rare Protopanaxadiol Saponin by Human Intestinal Microflora^†

HAN Mingxin, LI Fangtong, ZHANG Yan, DAI Yulin, ZHENG Fei, YUE Hao

2019, 40(7):  1390-1396.  doi:10.7503/cjcu20180812

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The rapid resolution liquid chromatography-quadrupole time-of-flight mass spectrometry(RRLC-Q-TOF MS) method and ultra high performance liquid chromatography-triple quadruple mass spectrometry(UPLC-QQQ MS) method were applied for qualitative and quantitative analyzing the biotransformation process of rare protopanaxadiol saponin Rd, Rg₃, F₂, CK and Rh₂ under intestinal micro flora in vitro. The rare protopanaxadiol saponin Rd, F₂, Rg₃, CK, Rh₂ and intestinal micro flora were cultured in vitro at 37 ℃ under anaerobic condition. The mass spectrometrics detection with electrospray ionization under negative ion mode was applied for identifying the metabolites, monitoring content variation, and matching metabolic pathways. The results show ginsenoside Rd is mainly metabolized into five products of F₂, Rg₃, CK, Rh₂ and PPD. Ginsenoside F₂ is mainly metabolized into two products of CK and PPD. Ginsenoside Rg₃ is mainly metabolized into two products CK and PPD. Ginsenosides CK and Rh₂ are both mainly metabolized into one product PPD. Ginsenosides Rd, F₂ and Rg₃ are metabolized completely into metabolic products, but ginsenosides CK and Rh₂ are not, under human intestinal micro flora condition in vitro. The results also indicated that deglycosylation reaction was the major metabolic pathway of rare protopanaxadiol saponin under the human intestinal microflora condition. And that monoglycosides and aglycone may be the material basis for rare protopanaxadiol saponin to exert its efficacy in human body.



Organic Chemistry

Synthesis of Benzothiazole Fluorescent Probe for Detection of N₂H₄·H₂O and HS{{\mathrm{O}}_3^{-}}^{†}

WANG Jinjin,QI Shaolong,DU Jianshi,YANG Qingbiao,SONG Yan,LI Yaoxian

2019, 40(7):  1397-1404.  doi:10.7503/cjcu20190159

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Based on benzothiazole as fluorophore, ethyl cyanoacetate as recognition group, a new fluorescent probe 3-(2-hydroxy-benzothiazole)-2-cyano-ethyl acrylate(HBT-CN) with dual detection ability for hydrazine hydrate and bisulfite was designed and synthesized. In DMSO/PBS(1：4, volume ratio) buffered condition, the probe displayed good selectivity towards hydrazine and bisulfite with approximate 5.6 times(500 nm) and 7.5 times(458 nm) fluorescence enhancement at 500 and 458 nm, respectively. ¹H NMR, ¹³C NMR and HRMS results showed that during the detection process, HBT-CN undergoed a reduction-condensation reaction with N₂H₄·H₂O, which form a aldehyde hydrazone and emited pale yellow fluorescent signal at 500 nm. And HBT-CN under went a nucleophilic addition reaction with bisulfite and emited blue fluorescent signal at 458 nm. So, differential qualitative and quantitative detection of N₂H₄·H₂O and HS{\mathrm{O}}_3^{-} can be achieved.



Effects of Curcumin on Growth and Oxide Regulation of Esophageal Cancer KYSE410 Cells^†

ZHOU Xinyuan,HONG Jiaxin,HE Shaobing,ZHANG Lianru

2019, 40(7):  1405-1410.  doi:10.7503/cjcu20190129

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This work took esophageal cancer KYSE410 cells as the research object. [3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium(MTS) method and some other techniques were used to study the effect of curcumin on growth and metabolism of KYSE410 cells. The results show that curcumin strongly inhibited growth of KYSE410 cells and half maximal inhibitory concentration(IC₅₀) was 17.9 μmol/L. Besides, the level of superoxide dismutase(SOD) decreases to 43.2% and the malondialdehyde(MDA) increases to 125.1%. Also, the level of lactate decreases to 44.4% and the activity of lactate dehydrogenase decreases to 58.2% and the activity of pyruvate kinase increases to 216.7%. It is presumed that curcumin has strong suppressed effect on this kind of cell. Curcumin can interfere oxidative stress and inhibit glycolysis by decreasing activity of lactate dehydrogenase and increasing activity of pyruvate kinase.



Tribological Behaviour of Protic Ionic Liquid Composed of 2-Ethylhexylethylenediaminium Cation and Trifluoromethanesulfonate Anion as Liquid Paraffin Additive^†

LI Chenguang, HUA Er, LIU Tianxia

2019, 40(7):  1411-1417.  doi:10.7503/cjcu20180819

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Tribological behavior of HEtHex(TFS) as additive in liquid paraffin(LP, simulant of lubricating base oils) with different mass fractions for the contact of steel/steel ball was investigated. At the same time, the effects of the temperature and load on the anti-friction and anti-wear properties were studied. The morpho-logies and the elemental compositions of the worn surfaces were analyzed using scanning electron microscope(SEM) and X-ray energy spectroscopy(EDS). The results showed that the value of extreme-pressure increased significantly, and the antifriction and anti-wear properties of the LP improved with the addition of HEtHex-(TFS). The optimum value of HEtHex(TFS) as additive in the LP was 0.75%(mass fraction). The best abilities for the anti-friction and anti-wear property of 0.75% HEtHex(TFS) in the LP were found at 25 ℃, 294 and 196 N, respectively. The results of the elemental analysis showed that a protective boundary film was formed on the steel ball surface and it caused that the anti-friction and anti-wear properties was improved.



Physical Chemistry

Synthesis and Electrochemical Performance of Carbon-coated FeF₂ Nanocomposite^†

YAO Fengnan,LI Yu,FENG Wei

2019, 40(7):  1418-1424.  doi:10.7503/cjcu20190169

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A hybrid nanostructure of FeF₂ coated by carbon was synthesized through thermal decomposition at high temperature, and its structure and morphology were characterized. The results show that FeF₂ is successfully coated by carbon, and Fe₃C is partially formed. The electrochemical measurements show the obtained material displays a reversible discharge capacity of 246.7 mA·h/g after 100 cycles at 0.1C, and the capacity retention is up to 93.6% compared with the discharge capacity at the second cycle, exhibiting excellent cycling stability.



Solvent and Substituent Effects on Spectral Characteristics and Excited-state Intramolecular Proton Transfer of 2-(2-Aminophenyl) Benzothiazole^†

LI Qing, YI Pinggui, TAO Hongwen, LI Yangyang, ZHANG Zhiyu, PENG Wenyu, LI Yuru

2019, 40(7):  1425-1432.  doi:10.7503/cjcu20190127

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A group of 2-(2-aminophenyl)benzothiazole(APBT) derivatives was synthesized with electron-donating or withdrawing substituent introduced at the nitrogen atom in amino. Solvent and substituent effects on their spectral characteristics and excited state intramolecular proton transfer(ESIPT) were further investigated by ultraviolet absorption spectrum, fluorescence emission spectrum and density functional theory(DFT) calculations. The results showed that, compared to non-polar solvent cyclohexane, the increase of solvent polarity and the formation of hydrogen bond between APBT and solvent molecule cause the maximum absorption peaks and fluorescence emission peaks of APBT red-shift a few nanometers. The ESIPT of APBT was also influenced to some extent by solvent effects. It was found that the charge distributions of nitrogen atom in amino be changed when substituent were introduced in APBT molecules. There were only a single fluorescence emission peak of APBT and its electron-donating substituent derivatives. The peaks were generated by enol tautomer and no ESIPT happened. However, the electron-withdrawing substituent, such as COCH₂Cl, would make the APBT derivatives to occur ESIPT reaction and the dual fluorescence peaks with different wavelength appeared in cyclohexane solution, which should be respectively assigned to enol and keto tautomers. The theoretical calculation of quantum chemistry agreed well with the spectral experimental results.



Promoted Formic Acid Electrooxidation Using PdN_x/C Catalyst Prepared with Hyperbranched Polymer^†

YU Yancun, WANG Xian, GE Junjie, LIU Changpeng, XING Wei

2019, 40(7):  1433-1438.  doi:10.7503/cjcu20190116

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Nitrogen-doped PdN_x/C(x denoted as the amine-terminate and palladium molar ratio) catalyst derived from hyperbranched polymer was prepared via in-situ polymerization, and the electrocatalytic oxidation of formic acid was investigated. The morphology and surface electronic state of the catalytically active component Pd were investigated by transmission electron microscopy(TEM), high resolution transmission electron microscopy(HRTEM), X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD). The results indicate that the Pd nanoparticles remain an average size of 2 nm using polymer modification, and maintain high dispersion, with surface Pd mainly presenting as Pd(0). Compared with the Pd/C catalyst, the Pd unit mass specific activity of PdN₂₀/C for formic acid electrooxidation was increased by 10.9%.



Theoretical Studies on Cationic Chalcogen and Pnicogen Bonds in Binary and Ternary Complexes^†

YI Jiang, QIN Xingmei, CHEN Feiwu

2019, 40(7):  1439-1446.  doi:10.7503/cjcu20190101

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The cationic chalcogen bonds and pnicogen bonds in binary complexes XH₂S⁺…NCH₂P and ternary complexes NCH₂P…PyX(X=NH₂, CH₃, H, CN, F, Cl, Br) with MP2/cc-pVDZ and cc-pVTZ were investigated theoretically. The effects of cationic chalcogen and pnicogen bond length, charge density ρ and ▽²ρ at bond critical points, van der Waals’s surface penetrating distance, the second order stabilization energy and charge transfer on the complex interaction energy were discussed. The results show that cationic chalcogen bond becomes stronger when the substituting group X is an electron-withdrawing group and that pnicogen bond becomes stronger when X is electron-donating group. The possible reason of the abnormal effect of the substituting group —CN on the stability of XH₂S⁺…NCH₂P complex was investigated with the energy-decomposition method. Further, we investigated the synergistic effects of cationic chalcogen and pnicogen bonds in the H₃S⁺…NCH₂P…PyX(X=NH₂, CH₃, H, CN, F, Cl, Br) complexes, and the influences of substituting group on the stability of these ternary complexes. By comparing the second-order stabilization energy and interaction energy of the monomers in these ternary and binary complexes, it is found that cationic chalcogen bond and pnicogen bond have positive synergistic effects on enhancing the stability of these ternary complexes.



Low Temperature NH₃-SCR Activity of Cr Doped V₂O₅-WO₃/TiO₂ Catalyst^†

LI Chunxiao, LI Jian, LIANG Wenjun, LIANG Quanming

2019, 40(7):  1447-1455.  doi:10.7503/cjcu20190091

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A series of different contents of Cr loading catalysts was prepared by impregnation method. De-NO_x activity and SO₂ resistance of Cr doped catalysts were measured and the result shows that the introduction of Cr promotes both of them obviously. When the amount of loading Cr(calculate as Cr₂O₃) is 3%, the catalyst possesses the best low-temperature De-NO_x activity and good N₂ selectivity. Analysis of catalyst characterization shows that the main valence state of chromium in Cr doped catalyst is Cr³⁺. Cr enhances the oxidation of catalyst while increasing the amount of weak, strong acid site and surface active oxygen. The XPS result indicates that loading of Cr decreases the ratio of V⁵⁺/V⁴⁺ and leads a result of the free electrons formed in non-stoichiometric V. The In situ DRIFTs shows Cr loading facilitates the reaction of NO and NH₃ absorbed on Brönsted acid site at low temperature and promote the NH₃-selective catalytic reduction activity.



Effect of Morphological Tuning on Electrochemical Performance of Perovskite LaCoO₃ Anodes^†

FANG Liang,DING Xiaoli,SONG Yun,LIU Dongming,LI Yongtao,ZHANG Qingan

2019, 40(7):  1456-1463.  doi:10.7503/cjcu20190074

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The perovskite-type LaCoO₃ electrode materials with the morphology of bulk, spherical nanoparticles(NPs) and three-dimensional porous framework(3DPF) were prepared to investigate the relations between the morphology and electrochemical lithium storage properties. It is demonstrated that the electrode materials with different morphologies all show the same perovskite structure, but there is a huge difference in specific capacities. At a current density of 500 mA/g, the specific capacities of the bulk, nano-particles, and three-dimensionally porous framework LaCoO₃ electrodes finally stabilized at 157, 579 and 648 mA·h/g, respectively. The improved specific capacity and cycling stability of porous framework LaCoO₃ are mainly attributed to the larger contact area between the active material and the electrolyte, the smaller particles, the more active sites, and the lower transfer resistance and better retention.



Investigation on Pseudo-polyanions of Cationic Cellulose-Sodium Dodecylbenzenesulfonate^†

HU Xueyi, CHEN Miaomiao, FANG Yun, FENG Ruiqin, HAN Huihui

2019, 40(7):  1464-1471.  doi:10.7503/cjcu20190057

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The complexation between typical cationic cellulose(JR400) and a typical anionic surfactant sodium dodecylbenzenesulfonate(SDBS) in aqueous solution was studied by nephelometry, tensiometry, zeta potential method and capillary electrophoresis(CE) in this paper. The turbidity and the zeta potential results show that precipitation zone(PZ) appears near to the isoelectric zone and shrinks with the declined concentration of JR400, and sediment disappears when SDBS in large excess, in addition to being less influenced by molecular weight and substitution degree of the cationic celluloses. The tensiometry results show that there are three critical concentration thresholds though the second critical concentration is commonly overlapped by PZ, which indicates the formation of complexes between SDBS and the polycations similar with “neutral polymer-anionic surfactant” systems. The zeta potential results show that the complexes formed ahead of PZ have the positive zeta potential so that keep the polycation properties, while behind the zone the negative in large excess of SDBS, and the latter is confirmed by CE being pseudo-polyanions. These experimental results and conclusions have great theoretical significance and practical value for studies of polycation-anionic surfactant systems.



Molecular Dynamics Simulation of Different Configurations of PAO Molecules in Shear Iron Plates^†

LIU Shasha, WANG Lin, YUAN Shiling, CAO Xiaorong

2019, 40(7):  1472-1479.  doi:10.7503/cjcu20190043

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The viscosity, friction and distribution of linear and branched polyalphaolefin(PAO) lubricants molecules on sheared iron plates were investigated with molecular dynamics simulation at the molecular level. The simulation results show that compared to the linear PAO lubricants, the shear viscosity of branched PAO lubricants are less affected by the shear rate; the friction coefficient of branched PAO lubricants is less than that of linear PAO lubricant; due to the presence of side chains, the branched PAO molecules are difficult to spread on the surface of iron, resulting into the complex network structure between different adsorbed layers of lubricants and reducing the mobility of branched PAO molecules under the additional shear force. The network structure of lubricants on the surface represents one stable lubricant film, and prolongs the life of lubricants.



Preparation and Oxygen Reduction Performance of Fe, N co-Doped arbon Nanoplate with High Density of Active Sites^†

YIN Wenjing, LIU Xiao, QIAN Huidong, ZOU Zhiqing

2019, 40(7):  1480-1487.  doi:10.7503/cjcu20190020

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Fe, N co-doped carbon nanoplate catalyst with high active sites was developed via methods of polymerization of triazine polyimide and carbonization within melting salt of ZnCl₂/KCl with the aid of g-C₃N₄ to anchor Fe³⁺. The as-prepared NPT-C₃N₄-0.5 catalyst displays high specific surface area of 1794 m²/g. The iron atoms uniformly distribute in the carbon skeleton with an increased doping amount up to the molar percentage of 1.13%, 3.3 times of the one without g-C₃N₄, which can be attributed to the coordination between g-C₃N₄ and iron to decrease its aggregation under high temperature. The catalyst exhibits excellent catalytic activity for oxygen reduction reaction(ORR) in acid media. Typically, the half-wave potential(E_1/2) of the catalyst can reach up to 0.79 V(vs. RHE) and only decreases by 30 mV after 10000 potential cycles of accelerated durability test in acid media, showing high activity towards ORR.



Synthesis of Amine Functionalized ZPS-PVPA Supported Chiral Mn^Ⅲ(salen) and Asymmetric Catalytic Olefin Epoxidation^†

ZOU Xiaochuan,WANG Yue,WANG Cun,HU Shiwen,SHI Kaiyun

2019, 40(7):  1488-1494.  doi:10.7503/cjcu20190011

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Using zirconium poly(styrene-phenylvinyl-phosphonate)-phosphate(ZPS-PVPA) as a catalyst carrier, the hydroxyl group in the inorganic zirconium hydrogen phosphate was modified by 3-aminopropyltrimethoxysilane. Then, the chiral Mn^Ⅲ(salen) was axially immobilized onto amine functionalized ZPS-PVPA. The immobilized catalyst were characterized by FTIR, DR UV-Vis, AAS, SEM, TEM, XPS, X-ray and EDS. The successful preparation of heterogeneous catalysts was confirmed. Subsequently, the catalytic performance of the supported catalyst for α-methylstyrene, styrene and indene was examined in detail. The results showed that the reaction was carried out at 0 ℃ for 3 h, the amount of catalyst was 0.03 mmol, the e. e. value was 91.5% with a 99% conversion when α-methylstyrene was investigated using m-chloroperoxybenzoic acid as oxidant and in the present of the axial ligand N-methylmorpholine nitrogen oxide(NMO). In addition, the recycling performance of the catalyst was examined using indene as a substrate. After 10 times of repeated use of the catalyst, the e. e. values(>90%)are significantly better than those achieved under a homogeneous counterparts(e. e. 65%).



Morphology Control and Lithium Storage Performance of Micro/nano Li-rich Cathode Material^†

YANG Jinge, LI Yujie, LU Di, CHEN Yufang, SUN Weiwei, ZHENG Chunman

2019, 40(7):  1495-1500.  doi:10.7503/cjcu20180829

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Hierarchical micro/nano Li-rich Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ cathode material was synthesized by urea-based hydrothermal method followed by a heat treatment. The structure and morphology of precursor particles and cathode material particles could be tailored by different reaction solvents. The fusiform Li-rich layered material Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ delivers an discharge capacity about 300 mA·h/g at a current density of 0.1C and 92 mA·h/g at 5C. Also, the cathode material has a capacity retention of 85% after 70 cycles at 0.5C, showing an excellent cycling performance and rate performance. This method is instructive for synthesizing other cathode materials in energy storage field.



Surfactant-assisted Formation of Nanoporous Pt Particles as Co-catalyst Loaded on P25 and Enhanced Photocatalytic Performance^†

JI Lei,GUO Fanzuo,WANG Kehan,WANG Lei

2019, 40(7):  1501-1509.  doi:10.7503/cjcu20180823

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Highly dispersed PtNi alloy particles were loaded on P25 as co-catalyst by chemical reduction in the presence of surfactant polyvinylpyrrolidone(PVP) and octoxinol(Triton X-100). The PtNi alloy particles were then de-alloyed to remove Ni atoms of the alloy selectively to obtain Pt nanoparticles having surface nanoscale hollow pore structure. The obtained sample showed an excellent activity for degrading the methylene blue(MB) dye and photocatalytic hydrogen production as compared with the case without the use of surfactant. This beneficial effect was ascribed to the following key factors: (1) the nanoporous structure increased surface area and active sites for H₂ production; (2) longer active site residence time of photogenerated electrons and reactants which is attributed to a confinement effect within the nanoporous structures. At the same time, the experimental results show that OH· and ·{\mathrm{O}}_2^{-} are the main active species of the photocatalytic degradation of MB.



Influence of Structure Evolution of CuY Catalyst During the Reaction Process on Its Catalytic Performance for Oxidative Carbonylation of Methanol^†

YIN Jiao, ZHANG Guoqiang, YAN Lifei, JIA Dongsen, ZHENG Huayan, LI Zhong

2019, 40(7):  1510-1519.  doi:10.7503/cjcu20180790

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Chloride-free CuY catalyst prepared by solid state reaction with NH₄Y zeolites as support and copper acetylacetone as copper source was evaluated for oxidative carbonylation of methanol to dimethyl carbonate(DMC). Combining the results of X-ray diffraction(XRD), N₂ adsorption-desorption isotherm, thermogravimetric(TG) analysis, NH₃-temperature-programmed desorption(NH₃-TPD), transmission electroon microscopy(TEM) and X-ray photoelectron spectroscopy(XPS) characterization, the influence of copper species evolution during the reaction process on its catalytic performance was disclosed. The results indicated that Cu⁺ was the dominant Cu species of fresh catalyst with the percentage of 48%. As the reaction proceeded, the active center Cu⁺ was gradually oxidized to Cu²⁺, and then formed CuO, part of which gradually migrated to the outer surface of the catalyst. With the reaction time extended to 100 h, the percentage of Cu⁺ gradually decreased to 36.7%, while the percentage of CuO continued to increase, accordingly resulting in the decrease of the space-time yield and selectivity of DMC and the increase of the selectivity of byproducts dimethoxymethane(DMM) and methyl formate(MF). With the reaction time extended to 190 h, the percentage of Cu⁺ decreased slowly to 33.6%, the space time yield and selectivity of DMC tended to be stable. When the reaction time extended to 300 h, the copper species in the catalyst remained unchanged, and the catalytic performance of the catalyst remained stable.



Polymer Chemistry

Preparation of PVA Two-dimensional Photonic Crystal Hydrogel and Its Responsive Behavior to Ethanol^†

REN Chenrui, LIU Genqi, QIN Xiatong, LIU Chenhui, FAN Xiaodong

2019, 40(7):  1520-1526.  doi:10.7503/cjcu20180862

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A poly(vinyl alcohol) two-dimensional photonic crystal hydrogel(PVA·2DPCH) was prepared by infiltrating poly(vinyl alcohol) aqueous solution into two-dimensional photonic crystal array using glutaraldehyde as a cross-linking agent. By measuring the diameter change of the Debye ring, the responsive behavior of PVA·2DPCH in ethanol aqueous solution was investigated. The results showed that the diameter of the Debye ring was nearly unchanged when ethanol volume fraction increasing from 0 to 60%. When ethanol volume fraction exceeded 60%, PVA·2DPCH showed very sensitive response to ethanol. The diameter of the Debye ring increased with the increasing of the volume fraction of ethanol, and the response time took only 30 s. In the range of 60%—100% ethanol volume fraction, the diameter change of Debye ring(ΔD) was linearly related to the ethanol volume fraction(V_e). In the range of 60%≤V_e≤75%, the linear regression equation is ΔD=50.30V_e-31.74, r²=0.9734. In the range of 75%<V_e≤100%, the linear regression equation is ΔD=111.14V_e-74.03, r²=0.9902. Based on these, a novel visual testing method for ethanol in aqueous solution by Debye ring method was established, and it was simple and fast, which is used to determine the ethanol content in medicinal alcohol with satisfied results.



Synthesis, Characterization and Photovoltaic Properties of Truxene Based Star-Shaped Non-Fullerene Acceptors^†

SONG Meining, HAO Haijing, CHEN Weiping, GU Fang, BA Xinwu

2019, 40(7):  1527-1534.  doi:10.7503/cjcu20180792

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Small molecular non-fullerene acceptors(NFAs) have recently drawn tremendous attention. In this work, a class of star-shaped NFAs, namely 2,2',2″-{[(5,5,10,10,15,15-hexahexyl-10,15-dihydro-5H-diindeno[1,2-a：1',2'-c]fluorene-2,7,12-triyl)tris(thiophene-5,2-diyl)]tris(methanylylidene)}tris(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene)trimalononitrile(NFT-C6) and 2,2',2″-{[(5,5,10,10,15,15-hexadecyl-10,15-dihydro-5H-diindeno[1,2-a：1',2'-c]fluorene-2,7,12-triyl)tris(thiophene-5,2-diyl)]tris(methanylylidene)}tris(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene)trimalononitrile(NFT-C10), have been designed and synthesized by an alkyl-substituted truxene as the central group and three strong electron withdrawing cyano-1,3-indanone as the terminal groups. The highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) energy levels of the compounds both lies at -5.66 and -3.75 eV, respectively. The NFT-C6 and NFT-C10 films show intense absorption from 400 nm to 700 nm with a maximum at 606 and 586 nm, respectively. The polymer solar cells(PSCs) devices using (PBDB-T=poly{[(2,6-{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]-benzo[1,2-b：4,5-b']dithiophene})-alt-{5,5-[1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c：4',5'-c']dithiophene-4,8-dione]})(PBDB-T) as a donor, and NFT-C6 or NFT-C10 as an acceptor have been fabricated, which shows a power conversion efficiency(PCE) of 1.09% and 5.23%, respectively. The external quantum efficiency(EQE) spectra indicated broad photocurrent response from 300 nm to 700 nm of the devices. The aggregation properties of the device have been investigated by atomic force microscopy(AFM). The height and phase images of the active layers indicated that the PBDB-T： NFT-C10 based film showed proper phase separation with dozens of nanometers, which was benefit to exciton dissociation and produced desired device performance. On the other hand, the low short-circuit current density, fill factor and PCE of the ITO/ZnO/PBDB-T：NFT-C6/MoO₃/Ag photovoltaic device was attributed to the overlarge phase separation size between the donor and the acceptor. These results demonstrated that truxene based star-shaped NFAs have promising application in PSCs devices.



Synthesis and Antioxidant Capacity of Dendrimer Bridged Antioxidant with Semi-hindered Phenolic Groups^†

LI Cuiqin, ZHAI Xue, SUN Peng, GAO Yuxin, ZHANG Zhiqiu, WANG Jun, LI Feng

2019, 40(7):  1535-1543.  doi:10.7503/cjcu20180749

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A dendrimer bridged antioxidant with semi-hindered phenolic groups and symmetrical structure was synthesized using 1.0G dendrimer as raw material. The structure and the purity of the dendrimer bridged antioxidant with semi-hindered phenolic groups were verified by elemental analysis, Fourier transform infrared spectoscopy(FTIR), ¹H nuclear magnetic resonance spectroscopy(¹H NMR), mass spectrometry(MS) and cryoscopic method. The antioxidant capacity of the dendrimer bridged antioxidant with semi-hindered phenolic groups was evaluated by the 1,1-diphenyl-2-picrylhydrazine(DPPH) assay and differential scanning calorimetry(DSC) method, and its antioxidant capacities was compared with those of the corresponding dendrimer bridged antioxidant with total-hindered phenol groups. The results showed that the free radical scavenging activities of the dendrimer bridged antioxidant with semi-hindered phenolic groups were affected not only by the antioxidant concentration but also by the reaction time. The antioxidant activity at the scavenging time of 30 min was about twice of which at the scavenging time of 400 min for the dendrimer bridged antioxidant with semi-hindered phenolic groups. Because of the semi-hindered phenolic effect, the antioxidant capacity of the dendrimer bridged antioxidant with semi-hindered phenolic groups was superior to that of the corresponding dendrimer bridged antioxidant with total-hindered phenolic groups in DPPH system and high density polyethylene(HDPE) resin.



Preparation of Polybenzimidazole/Polyvinylpyrrolidone Proton Exchange Membranes for Vanadium Redox Flow Battery^†

SONG Xipeng, LIU Jinyu, WANG Lihua, HAN Xutong, HUANG Qinglin

2019, 40(7):  1543-1551.  doi:10.7503/cjcu20180720

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A series of proton exchange membranes(PEMs), based on polybenzimidazole(PBI) with different mass ratios of polyvinyl pyrrolidone(PVP) loadings, was prepared and investigated in vanadium redox flow battery(VRFB). The results showed that the addition of PVP effectively increased the water absorption, acid doping level(ADL) and proton conductivity of the PBI membrane. All membranes exhibit lower vanadium permeability than that of Nafion115 membrane, which were widely used in VRFB. Especially, the PBI/PVP-5 membrane exhibited higher bonded acid level of 2.47 mmol/g and proton conductivity of 4.81 mS/cm than that of PBI/PVP-0, as a result, the selectivity(3.12×10⁵ S·min·cm^-3) of PBI/PVP-5 is twice as much as the original PBI membrane(1.12×10⁵ S·min·cm^-3). At the current of 120 mA/cm², the voltage efficiency(VE=71.60%) and energy efficiency(EE=70.9%) of the cell employing PBI/PVP-5 increased about 10% compared with the original PBI membrane, respectively. The self-discharge time of VRFB assembled with PBI/PVP-5 reached to 307 h. All experimental results reported in this paper indicate that incorporation of PVP can increased water update(WU), ADL and proton conductivity of the PBI membrane at the same time. PBI/PVP proton exchange membranes, especially PBI/PVP-5 show promising prospects for VRFB applications.



Preparation and Osteogenic Induction Activity of CBD-BMP2-MP/PLGA 3D Printed Composite Scaffolds^†

LIU Guomin, LU Tiancheng, JI Xuan, JIA Wenyuan, LI Yalong, ZHAO Yian, LUO Yungang

2019, 40(7):  1552-1560.  doi:10.7503/cjcu20190145

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Collagen binding domain(CBD) was conjugated to bone morphogenetic protein-2 mimetic peptide(BMP2-MP) to prepare collagen-binding BMP2-MP(CBD-BMP2-MP), then, CBD-BMP2-MP was combined with PLGA/collagen(PLGA/COL) composite scaffold for the surface modification of scaffold. SEM, electronic universal testing machine and contact angle measuring instrument were used to evaluate the surface morphology, mechanical strength, hydrophilicity and other material properties of PLGA/COL scaffolds. The binding abilities of CBD-BMP2-MP and BMP2-MP to scaffold materials were evaluated by immunofluorescence analysis. Subsequently, MC3T3-E1 cells were grown on different scaffolds, and cell proliferation, adhesion and osteogenic differentiation on different scaffold were evaluated by CCK-8, fluorescence staining, ARS and qPCR. The results show that the 3D porous scaffold has regular and controllable pore structure, which can create more favorable cell microenvironment for cell growth. The addition of collagen on the scaffold surface improved the hydrophilicity of material, and had no effect on the mechanical properties of material itself, which greatly improved the biocompatibility of the 3D scaffold. Compared with commercial BMP2-MP, CBD-BMP2-MP had better collagen binding ability, which improves the combining capacity of growth factor and PLGA/COL scaffold. The scaffold surface loaded with CBD-BMP2-MP has a strong ability to promote osteoblastic differentiation. MC3T3-E1 cells showed higher calcium deposition capacity, and the levels of osteogenic related gens such as COI-1, Runx2, ALP and OPN were also significantly increased. The results indicated that CBD-BMP2-MP modified 3D porous PLGA/COL scaffold has good biocompatibility and osteogenic activity, and is a promising bone tissue repair material.



Surface Modification of Silica/carbon Black Derived from Rice Husks and Its Influence on Natural Rubber Composites^†

SUI Jiayang, LIU Xiaoyang, QIAN Miaomiao, ZHU Yanchao, XUE Beichen, FENG Yi, TIAN Yumei, WANG Xiaofeng

2019, 40(7):  1561-1570.  doi:10.7503/cjcu20190077

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Surface modification of silica/carbon black(SiCB) derived from rice husks was carried out by grafting with natural rubber latex(NRL). The effect of different pre-treatments on the grafting efficiency was investigated and the mechanical properties of NR/NRL-grafted SiCB vulcanizates were tested. The results indicated that the SiCB pre-treated by nitric acid and 3-(trimethoxysilyl) propyl methacrylate(γ-MPTMS) can be effectively grafted with NRL via the strong interfacial bonding. The above modified SiCB(SiCB_MR10) exhibited good dispersion state and superior reinforcement ability, attributed to the use of NRL as a compatibilizer for filler-matrix composites. The tensile strength, stress at 300% elongation and tear strength of NR/SiCB_MR10 were 61.06%, 27.15% and 15.90% higher than those of NR/SiCB_P, respectively. The modified SiCB_MR10 achieved the similar reinforcement with the conventional carbon black(N774) in mechanical properties of NR vulcanizate. The results showed that SiCB_MR10 exhibited an ideal reinforcing effect on rubber.



Structure and Properties of Damping Materials with Super Fatigue Resistance Based on Chloroprene Rubber^†

ZHANG Xinping, ZHANG Jianping, CAI Lei, ZONG Xin, HE Aihua

2019, 40(7):  1571-1578.  doi:10.7503/cjcu20190016

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A new type of synthetic trans-1,4-poly(butadiene-co-isoprene) copolymer rubber(TBIR) was introduced into the traditional chloroprene rubber(CR) as damping matrix for railway track damping rubber cushion. It was found that CR/TBIR blends exhibited excellent comprehensive properties including significantly increased tensile strength and modulus of the CR/TBIR compounds, the obviously improved tensile strength, tear strength, compression permanent deformation, dynamic and static stiffness ratio and fatigue resistance of the CR/TBIR vulcanizates. Especially, the 1st flexural fatigue lifetimes showed 50%—400% improvements for unfilled CR/TBIR vulcanizates and 40%—180% improvements for the filled CR/TBIR vulcanizates; the 6th flexural fatigue lifetimes showed 60%—500% improvements for the unfilled CR/TBIR vulcanizates and 30%—120% improvements for filled CR/TBIR vulcanizates. Compared with the unfilled CR/TBIR vulcanizates, the 1st flexural fatigue lifetime, tear strength and tensile property of the filled CR/TBIR vulcanizates improved greatly, which were attributed to the better filler dispersion and improved filler-polymer interactions in the CR/TBIR vulcanizates. Compared with pure CR vulcanizate, m(CR)：m(TBIR)=90：10(mass ratio) vulcanizate exhibited balanced comprehensive performances with loss factor changed little.