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Table of Content

    10 December 2019, Volume 40 Issue 12
    Contents
    Articles: Inorganic Chemistry
    Synthesis of Highly Luminescent Carbon Dots@Polyacrylate Sodium Composites with High Loading Fraction and Their Application in Light-Emitting Diodes
    Zijie WU,Xin LI,Zhiwei LI,Di LI,Yuechen ZHAI,Ding ZHOU,Songnan QU
    2019, 40(12):  2427-2435.  doi:10.7503/cjcu20190481
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    Luminescent materials have wide application prospects in many fields, and hence they have drawn increasing attention. In this work, carbon dots(g-CDs) and polyacrylate sodium(PAAS) were used as raw materials. By combining g-CDs aqueous solution with PAAS, a luminescent composites(g-CDs@PAAS) was obtained. Because the PAAS has a large number of carboxyl group and strong water imbibition thereof, while there are lots of carboxyl, hydroxyl and amino groups on g-CDs surface, leading to the combination of PAAS with g-CDs through hydrogen bonding interaction. In the as-prepared composites, g-CDs maintain monodisperse, which effectively overcomes the aggregation-induced solid-state luminescence quenching of g-CDs. This synthetic method is simple to operate and has no loss of raw materials during the preparation. The loading g-CDs fraction in g-CDs@PAAS is up to 30%, and its photoluminescence quantum yields could achieve 52%. In addition, the g-CDs@PAAS composites have good thermal stability, photostability, and organic solvent resistance. These advantages ensure that g-CDs@PAAS composites can be used as the color conversion layer in the manufacturing of white light-emitting diode.

    Preparation and Catalytic Performance of Bowl-shaped Amphiphilic ZSM-5 Zeolites Supported Gold Nanoparticles
    Siqi SUN,Ying WANG,Chuanyin SUN,Runwei WANG,Zhendong ZHANG,Zongtao ZHANG,Shilun QIU
    2019, 40(12):  2436-2442.  doi:10.7503/cjcu20190415
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    Bowl-shaped amphiphilic ZSM-5 zeolites, which have a lipophilic outer surface and a modified hydrophilic inner surface, were prepared by asymmetric modification via a classical amino graft-in situ reduction process. The gold nanoparticles were selectively grown on the inner surface of the zeolites. The samples were characterized by means of XRD, SEM, TEM, IR and XPS, and their catalytic properties for hydrogenation of nitrobenzene to aniline were investigated. Under very mild conditions(room temperature, water as solvent, without nitrogen protection) and lower reactant concentration(0.03 mol/L, lower than the solubility of nitrobenzene in water at room temperature), the catalyst exhibited the same catalytic activity and selectivity as other catalysts using organic solvents, and was significantly higher than other catalysts using water as catalyst. The amphiphilic structure of the support was proved to be the main reason for improving the catalytic effect. After six cycles, the catalytic activity and selectivity of the catalyst remained at the same level.

    Synthesis and Physical Properties of Cobalt-Zinc Hybrid Porous Metal-organic Frameworks
    Baozhen SHI,Shan LI,Dianpeng WANG,Yunzhi ZHOU,Jinyu SUN
    2019, 40(12):  2443-2447.  doi:10.7503/cjcu20190395
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    Coordination polymer ZnCo(BTC)(OH)(H2O)3(NMP)(DMF)(H2O)1.5 was synthesized by slowly diffusing a balanced amount of organic amine into a solution of 1,3,5-benzenetricarboxylate(H3BTC), zinc nitrate and cobalt nitrate. X-ray single crystal diffraction shows that the compound crystallizes in cubic, space group P213, and its cell parameter is 1.43863(20) nm. Its physical properties were characterized by elemental analysis(EA), energy-dispersive X-ray spectroscopy(EDS), X-ray powder diffraction(XRD), N2 sorption and variable-temperature magnetic susceptibility. The gas sorption shows this compound holds Ⅰ-isotherm characteristic of micropore, which is 0.84 nm of pore size and 832 m 2/g of langmiur surface area. The magnetic results show that it exhibits antiferromagnetism in the temperature range of 37—300 K.

    Structure and Host Luminescence of YXO4(X=Nb, V)
    Hongjie WANG,Chongyang ZHU,Su ZHANG,Ran PANG,Lihong JIANG,Da LI,Guanyu LIU,Jize CAI,Jing FENG,Chengyu LI
    2019, 40(12):  2448-2455.  doi:10.7503/cjcu20190352
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    A series of YNb1-xO4xV samples were synthesized by high temperature solid phase method. Different structures were obtained by continuously varying the concentrations of Nb and V. It was found that the luminescence of the V$O^{3-}_{4}$ group and the luminescence of the Nb$O^{3-}_{4}$ group are located at around 420 and 400 nm. However, the small amount of V 5+ doping in YNbO4 and the small amount of Nb 5+ doping in YVO4 have significantly different effects on their luminescent behaviors. By continuously varying the ratio of V and Nb, the luminescent properties do not continuously change from one characteristic luminescence to another, but reach the minimum emission intensity at a certain composition. In this paper, the changes in structure, composition and luminescence were studied. The results show that there are two luminescence quenching mechanisms.

    Facile Strategy to Prepare Fluorescent Porous Aromatic Frameworks for Sensitive Detection of Nitroaromatic Explosives
    Lixin XIA,Hongcui ZHANG,Bin FENG,Dongqi YANG,Naishun BU,Yunbo ZHAO,Zhuojun YAN,Zhangnan LI,Ye YUAN,Xiaojun ZHAO
    2019, 40(12):  2456-2464.  doi:10.7503/cjcu20190284
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    Three fluorescent porous aromatic framework materials donated as LNU-9, LNU-10, and LNU-11 were prepared via Suzuki coupling reactions of 1,3,6,8-tetrabromofluorene(TBrPy) with boric acid monomers. The structures and properties of the LNUs were characterized by Fourier transform infrared spectro-scopy(FTIR), thermogravimetric analysis(TGA), nitrogen adsorption-desorption, solid ultraviolet spectroscopy and fluorescence spectroscopy. The disappearance of vibration peaks at 1349, 1144, 495 cm -1 in FTIR spectrum is attributed to the breakage of C—Br and C—B(OH)2 bonds, respectively, indicating the complete polymerization of building monomers into porous skeletons. Powder X-ray diffraction(PXRD) and transmission electron microscopy(TEM) images reveal all the LNUs have amorphous structure. The thermogravimetric ana-lysis results demonstrate the excellent thermal stability of LNUs. In addition, these materials exhibit high chemical stability, as verified by no dissolution or decomposition in various organic solvents such as methanol, ethanol, tetrahydrofuran, acetone, dichloromethane, chloroform, N,N'-dimethylformamide, dimethylsulfoxide, etc. Besides, their large specific surface areas in the range of 800—1500 m 2/g and excellent fluorescence properties make them suitable for the detection of specific nitro explosives. After benzene, bromobenzene, aniline, toluene, chlorobenzene and phenol were added into the methanol solution of LNUs respectively, the luminescence intensity had little change, demonstrating there is no specific interaction between porous skeleton and organic substances. On the contrast, fluorescence of LNUs was almost completely quenched in the respective solution of nitrobenzene, p-nitrophenol, and p-nitrochlorobenzene, indicating the selective detection capability for nitro compounds of the LNUs. Based on these results, we prepared a novel portable paper sensor which realized the facile and rapid real-time detection of nitro explosives, demonstrating an impressive pro-spect in trace detection.

    Analytical Chemistry
    Rolling Circle Amplification-based Polyvalent Molecular Beacon Probe for Signal-amplifying and Sensitive-Detection of Thrombin
    Zhiqing ZHANG,Shanshan WANG,Zichen ZHANG,Jie MA,Xiufeng WANG,Ting ZHOU,Fang WANG,Guodong ZHANG
    2019, 40(12):  2465-2470.  doi:10.7503/cjcu20190450
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    A long chain structure of DNA synthesized by rolling circle amplification(RCA) was used to turn on aptamer-based molecular beacons(MBs). Owing to the multiple complementary repeat units, the RCA scaffold can hybridize tens or hundreds of MBs to form polyvalent aptamer probes. The unfold ability and the fluorescence intensity of MBs were both improved by RCA compared to short single chains. Experimental results demonstrated that the system is significantly more effective than monovalent molecular beacon in targeting thrombin and signal sensitivity because of multivalent effects. Once the poly valent molecular beacon binding to the thrombin, there was a linear relationship between fluorescence signal and thrombin concentration, and the detection limit of thrombin concentration was 0.2 nmol/L. The establishment of this system is conducive to the realization of highly sensitive and specific detection of thrombin.

    3D-QSAR Model of Polybrominated Biphenyls Tri-effect Modified by Standard Deviation Standardization Method and Its Application in Environmental Friendly Molecular Modification
    Luze YANG,Miao LIU
    2019, 40(12):  2471-2479.  doi:10.7503/cjcu20190402
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    A CoMFA model of tri-effect comprehensive values of infrared vibration intensity, bioconcentration and toxicity of PBBs via standard deviation method was constructed. The influence of PBBs’ molecular force fields on comprehensive values were analyzed to determine substitution sites. And the modification for PBB-153 with easy infrared detection, low bioconcentration and toxicity was accomplished. The CoMFA model had a good fitting and predicting ability on PBBs comprehensive values of infrared vibration intensity, bioconcentration and toxicity and had a good stability, the influencing force fields were electrostatic fields(E, 59.9%) and steric fields(S, 40.1%), respectively. Five substituents with higher electropositivity than Br were selected for single and double substitution of the target molecule PBB-153 according to the contour maps of CoMFA model, and six PBB-153 derivatives with increased tri-effect comprehensive values were screened. Predicting or calculating results of single effect of PBB derivatives indicated that the constructed CoMFA model can be applied to the modification of PBBs molecules. In addition, the flame retardancy and environmental friendliness of designed derivatives was comparable to the target molecule and the stability of derivatives was well. The results of 2D-QSAR model showed that the influence trends of dipole moment, maximum negative charge and the number of ortho Br atomic on the three single effects and comprehensive values were consistent.

    Benzimidazole-Derived Fluorescence Enhancement Probe for Visual Detection of HClO
    Yong ZHANG,Cheng SHEN,Zhirong XING,Guiqi CHEN,Zi LU,Zhibing HOU,Xuemei CHEN
    2019, 40(12):  2480-2485.  doi:10.7503/cjcu20190366
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    A novel benzimidazole-derived fluorescence enhancement probe 2-{[4-(1H-benzo[d]imidazol-2-yl)benzylidene]amino}-3-aminoma-leonitrile(ZY12) was synthesized, and its recognition of HClO was researched with spectral methods. The results showed that ZY12 demonstrated relatively high selectivity and sensitivity to ClO -. It had quick response and strong anti-interference ability. Upon addition of ClO - to ZY12 solution, the fluorescence intensity of reaction system increased with the increasing concentration of ClO -, accompanied with fluorescence color change from faint blue to bright blue, realizing the visual detection of ClO -. ZY12 could quantitatively detect ClO - at concentrations ranging from 1.8×10 -6—3.4×10 -5 mol/L with a detection limit of 2.8×10 -7 mol/L. ZY12 was used to determine ClO - in various water samples, and it could also be applied to intracelluar ClO - imaging in living HeLa cells.

    Synthesis of a Colorimetric Fluorescent Probe of Cr 3+ and Its Application in Cell Imaging
    Yingying ZHANG,Yiwen HUANG,Bing ZHAO,Liyan WANG,Bo SONG
    2019, 40(12):  2486-2493.  doi:10.7503/cjcu20190354
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    Colorimetric fluorescence probe B was synthesized from 2,3,3-trimethyl-3H-benzo[e]indole and p-dimethylaminobenzaldehyde using acidic solvent as catalyst and ethanol as solvent. In the mixed system(pH=7.4) of V(EtOH)∶V(HEPES)=9∶1, the color of solution B changed from pale yellow to purple-red after added Cr 3+ to probe B solution, indicating that probe B can recognize Cr 3+ with naked-eye. Fluorescence emission spectra shows that probe B had good selectivity of Cr 3+, high sensitivity and good recognition ability with EDTA. The binding constant(Ka) of probe B on Cr 3+ was 0.28×10 2 mol/L and the detection limit was 1.90×10 -8 mol/L. The detection limit was lower than the maximum Cr 3+ content(9.60×10 -8 mol/L) in drinking water stipulated by WHO. In addition, the concentration of Cr 3+in actual water samples was quantitatively detected by fluorescence emission spectra. Probe B has been applied to the detection of Cr 3+ in living cells, which has a good application prospect and practical value.

    Multiple Analyses of Tumor Invasion Based on an Integrated Microfluidic System with Bi-directional Solute Concentration Gradient
    Jie WANG,Yu ZHANG,Min YU,Jin FANG
    2019, 40(12):  2494-2501.  doi:10.7503/cjcu20190206
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    A simple integrated microfluidic system with continuous 2D concentration gradient for multiple evaluation of tumor invasion was developed. The continuous bi-directional gradient was established vertically by solute diffusion and horizontally by Christmas tree-shaped network. The microfluidic system managed to quantitatively evaluate different invasive potentials of different cell lines(HEK-293, MCF-7, SGC-7901) and effects on tumor invasion by multiple factors. Human gastric cancer SGC-7901 cells were driven to invade into matrix under vertical FBS(Fetal bovine serum) gradient and revealed an increased invasion distance with the obvious concentration gradient. Given the continuous bi-directional gradient of FBS and Staurosporine, the invasion distance and increased number of human gastric cancer SGC-7901 cells were gradually inhibited along with the increase of drug concentration. In conclusion, the established bi-directional gradient microfluidic system provides multifunctional application in investigation of tumor invasion, cell interaction under complex environmental factors or combined chemotherapy.

    Organic Chemistry
    Synthesis and Biological Activity in vitro of Imidazo[4,5-c]quinoline Derivatives
    Yanjie LI,Ensi WANG,Xiaowei SHAO,Xingmin ZHANG,Shengxiu NIU,Lijuan YANG,Yi WU
    2019, 40(12):  2502-2511.  doi:10.7503/cjcu20190544
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    In search of new and efficient PI3K/mTOR inhibitor based on the imidazoquinoline structural framework, 15 novel imidazo[4,5-c] quinoline were synthesized via SNAr reaction of 4-chloroquinoline with aniline, the Traube condensation reaction of aromatic diamine with triphosgene and the Suzuki coupling reaction of bromo-compounds with 3-quinoline boronic acid. The structures of the key intermediates and target compounds were confirmed by 1H NMR, 13C NMR and HRMS. Imidazo[4,5-c] quinolin analogues(8Aa—8Ae, 8Ba—8Be, 8Ca—8Ce) were evaluated for their in vitro activities against PI3Kα/mTOR by ADP-Glo kinase assay and TR-FRET assay, all compounds displayed strong activities.

    Physical Chemistry
    Construction and Catalytic Performances of Fe-aminoclay Nanostructured Lipase
    Xiaoyu FAN,Ke WANG,Shiyong SUN,Biaobiao MA,Rui LÜ
    2019, 40(12):  2512-2520.  doi:10.7503/cjcu20190444
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    Lipase from Aspergillus oryzae was immobilized on Fe-aminoclay support via 1-(3-dimethylami-nopropyl)-3-ethylcarbodiimide hydrochloride(EDC) as covalent crosslinking agent. The nanocomposite structure of immobilized lipase(Feclay-lipase) was characterized by means of X-ray diffraction(XRD), transmission electron microscope(TEM) and Fourier transform infrared spectroscopy(FTIR). The enzymatic properties of free lipase and Feclay-lipase were studied by enzymatic kinetics. The results showed that the optimal immobilization efficiency of Feclay-lipase was 82.88%, immobilization capacity was 414.4 mg/g support, and the enzyme activity was 28.24 U/mg, which was three times higher than that of free lipase(8.21 U/mg). The optimum reaction temperature of Feclay-lipase increased from 45 ℃ to 55 ℃, the optimum pH shifted to alkalinity, and the catalytic activity of Feclay-lipase did not decrease significantly after storage at 4 ℃ for one month.

    Main Luminescent Centers of Carbonized Polymer Dots
    Xue ZHANG,Yijia GENG,Songyuan TAO,Shuping XU,Weiqing XU
    2019, 40(12):  2521-2525.  doi:10.7503/cjcu20190401
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    Polyacrylic acid and ethylenediamine were used as precursors to synthesize carbonized polymer dots(CPDs) by hydrothermal method. Fluorescence spectroscopy and time-dependent single photon counting were used to characterize the CPDs formed under different carbonization temperatures(200, 240 and 280 ℃). The luminescence mechanism of these CPDs was explored by comparing their fluorescence lifetimes and the photobleaching process under a 375 nm light. The results prove that the luminescence of these CPDs are contributed by both the carbon core state and the molecular state.

    Preparation and Electrochemical Properties of Calcium Bronze/Carbon Nanotubes Composites
    Jian LIU,Haihui DU,Tianjiang SUN,Qingshun NIAN,Haixia LI,Zhanliang TAO
    2019, 40(12):  2526-2533.  doi:10.7503/cjcu20190397
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    A new layered material, calcium bronze(CaxV2O5·nH2O, CVO) nanoribbons as cathode materials of aqueous zinc ion batteries(AZIBs) was prepared by hydrothermal method. Three kinds of calcium bronze@carbon nanotubes composites(CVO@CNTs) were synthesized by adjusting the content of CNTs in the precursor solution. The synthesized CVO had a fine nanobelts structure with a length of about 10 μm and a width of several hundred nanometers. Selected area electron diffraction(SAED) spectrum showed that CVO was single crystal. The CV test revealed that the CVO had multiple redox peaks, corresponding to different stages of zinc ion insertion/desertion. The zinc storage mechanism includes pseudocapacitive behavior and battery behavior. When applied as the cathode material of AZIBs, the specific capacity of CVO was stable at 210.1 mA·h/g at a current rate of 1C(1C=300 mA/g). The addition of CNTs could decrease the charge transfer impedance of CVO@CNTs composites. More importantly, the one-dimensional CTNs twisted between the nanoribbons could effectively avoid the stack of nanoribbons, increase the contact area between active materials and electrolyte, and improve the utilization of active materials. Therefore, CVO@CNTs composites exhibited a higher capacity at the same test condition. Among them, CVO@CNTs-40 exhibited a highest specific capacity of 274.3 mA·h/g at a current rate of 1C. What’s more, this cathode material delivered a high rate capability and high capacity retention of more than 92% over 1000 cycles, at a current rate of 20C.

    Molecular Dynamics Simulation of Adsorption of Methylene Blue by Graphene Oxide
    Ying MA,Tian WANG,Heng ZHANG
    2019, 40(12):  2534-2541.  doi:10.7503/cjcu20190392
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    The adsorption distribution and kinetic properties of methylene blue on graphene oxide surfaces with different oxidation degrees were studied by molecular dynamics method. The adsorption process and main mechanism of methylene blue from aqueous solution to graphene oxide surface were proposed from the trajectory displacement of methylene blue, and the reasons for the adsorption stability were explained. In the adsorption process, methylene blue is mainly attracted by the electrostatic attraction of oxygen-containing functional groups on the graphene oxide surface and enters the graphene oxide surface vertically, and is concentra-ted on the surface of the graphene oxide in a parallel manner firstly. Methylene blue is not easily desorbed from the adsorption site of high oxidation degree graphene oxide secondly. In the adsorption equilibrium process, comparing with the low oxidation degree graphene oxide, the interaction between the high oxidation degree graphene oxide and methylene blue is enhanced and more hydrogen bonds are formed to bind the methylene blue molecules movement in the adsorption layer, so that the interface between the graphene oxide and the methy-lene blue solution forms a stable adsorption layer.

    Study on Improving Storage Life of Lithium Ion Batteries Based on Construction of Polymer Functional Protective Film on the Surface of Graphite Anode
    Yujie LI,Yong LIU,Qizhi ZHAO,Chunman ZHENG
    2019, 40(12):  2542-2548.  doi:10.7503/cjcu20190387
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    Graphite anode uniformly coated with polyvinyl alcohol(PVA) was prepared by solution impregnation method. The morphology and electrochemical properties of graphite coated with PVA were stu-died. LiNi0.8Co0.15Al0.05O2(NCA) was used as cathode material and graphite coated with PVA was used as negative material to assemble soft-packed batteries. The effects of PVA coating on the electrical performance and storage life of full-scale batteries were studied. The results show that PVA coating can effectively inhibit the reaction between electrolyte and graphite-embedded lithium and prolong the storage life of the battery.

    Synthesis of Flower-like Structured Mn/CuO-CeO2 and the Catalytic Performance for CO Oxide Reaction
    Long TIAN,Yan LONG,Shuyan SONG,Cheng WANG
    2019, 40(12):  2549-2555.  doi:10.7503/cjcu20190382
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    The unique properties make CeO2 play important roles in many catalytic reactions. However, CeO2 alone as a catalyst is fairly unfavorable due to its low catalytic activity and poor stability for high-temperature reactions. Therefore, in this work, we constructed the composite of CeO2 and transition metal oxides for the purpose of increasing the stability and improving the catalytic performance of CeO2. We synthesized the Mn/CuO-CeO2 composite nanomaterials with different components and three-dimensional flower-like structures via solvent thermal method. The XRD patterns confirmed that the synthesis formed solid solutions affording the single phase of fluorite-type CeO2. And the SEM images showed the composites have flower-like structures which were assembled by numerous nanocrystals and the structural unit of each nanocrystal was nanoparticles with a size of about 10 nm. The catalytic activity of the catalyst increases successively in the order of CeO2<CuO-CeO2<xMn/CuO-CeO2 mainly associated with the strong interaction between constituents owing to the highly dispersed copper and manganese species. And with the increase of Mn doping, the catalytic activity of the composite increases first and then decreases. When nCenCunMn=25∶5∶2, the catalyst exhibited the best catalytic performance: the complete transformation of CO can be achieved at 173 ℃ in CO oxidation test, and it showed good stability.

    Corrosion Inhibition of Q235 Steel by Ionic Liquid Based on the 2-(Dimethylamino)ethyl Methacrylate
    Qiuchen DONG,Guanghua ZHANG,Wanbin ZHANG,Xue ZHANG,Jing LIU
    2019, 40(12):  2556.  doi:10.7503/cjcu20190370
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    A 2-(dimethylamino)ethyl methacrylate type ionic liquid with hydrophobic structure(DEMA) was prepared from 2-(dimethylamino)ethylmethacrylate and 4-vinylbenzyl chloride. The corrosion inhibitory property of DEMA on Q235 steel in 1 mol/L hydrochloric acid solution and their adsorption behavior on Q235 steel surface were studied by means of mass loss measurement, electrochemical technique, force microscopy(AFM), contact angle measurement and quantum chemical calculation. The mass loss results show that DEMA has good corrosion inhibition effect on Q235 steel in hydrochloric acid, and it can maintain strong adsorption at higher temperature(60 ℃). The results of electrochemical tests are consistent with that of mass loss test. Contact angle test results show that DEMA can significantly enhance the hydrophobicity of the surface of Q235 steel. Thermodynamic and activation energy parameters show that the adsorption of DEMA on Q235 steel surface is spontaneous and exothermic, conforming to the Langmuir’s adsorption isotherm and mainly based on chemical adsorption. Quantum chemical calculation results show that the entire structure of DEMA contains a large number of adsorbed active sites. Thermogravimetric analysis(TGA) shows that DEMA has good thermostability. DEMA has the advantages of mild preparation condition, good thermal stability and excellent corrosion inhibition performance, thus it has important industrial application value and theoretical reference. At the same time, the studies also provide a new idea for the structural design of corrosion inhibitor.

    Synthesis and Reusable Properties of Robust Al2O3-SiO2 Aerogel
    Enshuang ZHANG,Hongyan HUANG,Tao LIU,Lijuan HE,Hui GUO,Wenjing LI,Fan ZHANG,Jieying YANG,Hao ZHANG,Yingmin ZHAO
    2019, 40(12):  2566-2573.  doi:10.7503/cjcu20190369
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    An Al2O3-SiO2 composite aerogel with robust mechanical property was constructed by nanocrystalline assembly. Due to different heat resistance of Al2O3 and SiO2, robust Al2O3-SiO2 aerogel can be prepared by controlling treating temperature. The effects of Al/Si molar ratio and treating temperature on microstructure were studied and the best experiment condition was obtained. The aerogel gets densities of 0.25 g/cm 3, specific surface of 123.9 m 2/g, thermal coefficient of 0.029 W·m -1·K -1 fabricated in the best experiment condition. The test result showed that the microstructures of aerogel unchanged in extreme conditions such as water immersion and freeze. And thermal coefficient of aerogel still remains 0.029 W·m -1·K -1 after 10 cycles heat treatment(800 ℃, 30 min). The robust Al2O3-SiO2 aerogel is expected to solve the problem that thermal insulation material cannot be used repeatedly in future aerospace vehicles and near space vehicles. This method prove a new idea for new aerogel insulation materials.

    Synthesis and Electrochemical Properties of Spinel Lithium Manganese Cathode Material LiNi0.01Co0.03Mn1.96O4
    Yuzhen DUAN,Jinyu ZHU,Junming GUO,Mingwu XIANG,Xiaofang LIU,Hongli BAI,Changwei SU
    2019, 40(12):  2574-2582.  doi:10.7503/cjcu20190346
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    Ni-Co co-doped LiNi0.01Co0.03Mn1.96O4(LNCMO) cathode material with a polyhedral morphology was prepared via a solid-state combustion method. Results show that the LNCMO sample has excellent rate performance and long cycling stability, it delivers the initial discharge capacity of 110.6 and 102.3 mA·h/g with capacity retention rate of 75.7% and 78.3% after 1000 cycles at 1C and 5C at 25 ℃, respectively. At high current rate of 10C and 20C, the capacity retention rates of 78.8% and 54.2% are obtained after 1000 cycles, respectively. Even at 1C under high temperature of 55 ℃, the capacity retention rate of 76.6% is also maintained after 1000 cycles. The LNCMO sample shows larger Li + ion diffusion coefficient(4.77×10 -11 cm 2/s) and lower apparent activation energy(23.37 kJ/mol) compared to the Co-doped sample.

    Synthesis of Carbon Nanoparticles with Efficient Solid-state Emission and Its Application for Imaging of Latent Fingerprints
    Guiping WANG,Ping ZHANG,Guiyan WANG
    2019, 40(12):  2583-2589.  doi:10.7503/cjcu20190343
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    A facile reaction temperature-controlled pyrolytic method was developed to prepare solid-state fluorescent carbon nanoparticles(CNPs) using sodium citrate and urea as precursors. The obtained CNPs exhibit bright emission in the solid state without any other additional solid matrices. The phase, microstructure, surface functional groups, and optical properties of the CNPs were characterized by means of X-ray powder diffraction(XRD), transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), UV-Vis spectroscopy and photoluminescence spectra(PL). The results indicated that the CNPs were amorphous carbon structure, nearly spherical shape with diameter of ca. 5—15 nm, and C=O, C=N and O=C—N groups on the surface. Under 365 nm UV light excitation, CNPs exhibit bright blue-green emission in the solution and solid state. The CNPs powder was directly employed as fluorescent reagent for the visualization of latent fingerprints(LFPs) on different non-infiltrating surfaces. Results indicate that CNPs can be used as fluorescent probe to rapidly visualize the precision substructure of LFPs by the powder dusting method, showing high contrast with low background interference. Importantly, the CNPs powder could successfully achieve the fluorescent imaging for LFPs after aged for 30 d. The results demonstrate that CNPs could be used as a developer for effective latent fingerprint detection in forensic science.

    Construction of Ag2CO3/Bi2O2CO3 p-n Heterojunction and Its Photocatalytic Activity
    Junjin WANG,Guoying ZHANG,Yaqiu SUN,Jingwang LIU
    2019, 40(12):  2590-2597.  doi:10.7503/cjcu20190329
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    Ag2CO3/Bi2O2CO3(BOC) composite photocatalysts were prepared by a successive precipitation strategy. SEM and TEM results showed that Ag2CO3 nanoparticles were dispersively deposited on the surface of BOC nanosheets. A good p-n heterojunction structure was formed between the two semiconductors. The surface composite of Ag2CO3 effectively widened the light absorption of BOC and promoted the separation of photoinduced carriers. Accordingly, the photoactivity of Ag2CO3/BOC composite was greatly improved. In particular, the sample with Ag2CO3 content of 0.62% showed the best photocatalytic behavior with degradation rate improved by 1.8 times compared with that of BOC. Combining the detected oxidation species and the band positions of the semiconductors, the formation of space charge layer and the charge migration at the p-n heterojunction interface of Ag2CO3 and BOC were proposed.

    Preparation of Biochar with Mn Enriched in Iris and Its Application in Fenton-like System
    Huibin NIU,Yan GU,Changan ZHANG,Yingping HUANG,Yanfen FANG
    2019, 40(12):  2598-2605.  doi:10.7503/cjcu20190324
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    Mn enriched Brazilian iris(Neomarica gracilis) was converted into biochar and its potential application was studied, which provided a new transformation and application method for manganese enriched plant subsequent treatment. The Mn/biochar materials were obtained by pyrolysis of the Mn-rich Brazilian iris in a N2 atmosphere, and named them as BC-L0, BC-L1, BC-L2, BC-R0, BC-R1 and BC-R2 according to the leaf and root, respectively. SEM/EDS, XRD, XPS, AAS and specific surface area analyzer(SBET) were employed to characterize the morphology, chemical composition of Mn doped on biochar surface. The results showed that the leaf part of the iris was the main enrichment part of Mn, and the maximum Mn enrichment concentration was 13.0 mg/g. Mn2O3 flakes was present on the surface of biochar samples When H2O2 was added, the Fenton-like system could be successfully constructed. At 180 min, the degradation rate of RhB(3×10 -5 mol/L) in BC-L2/H2O2 system reached 50%, indicating that the system can be used to remove organic dyes. Furthermore, the possible catalytic oxidation mechanism of RhB in BC-L2/H2O2 system was proposed. The results of this study showed that by converting Mn-enriched plant into Mn/biochar material under suitable thermal cracking conditions, which helped to construct Fenton-like system and degrade toxic organic pollutants. This study provided the green approaching for treatment of cyclic waste treatment.

    Polymer Chemistry
    Comb-like Polymeric Pour Point Depressants with Aromatic Pandents and Asphaltenes Synergistically Improve the Flow Behavior of Model Waxy Oils
    Fei YANG,Xiaoping ZHANG,Chuanxian LI,Bo YAO,Shutong DAI,Xue XIA,Guangyu SUN
    2019, 40(12):  2606-2614.  doi:10.7503/cjcu20190394
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    The influence of poly-octadecyl acrylate-maleic anhydride(POM), poly-octadecyl acrylate-maleic anhydride-aniline(POMA) and poly-octadecyl acrylate-maleic anhydride-naphthylamine(POMN) copolymers on the flowability of model waxy oil with/without asphaltenes was investigated through rheological tests, differential scanning calorimeter(DSC) analysis, microscopic observation and asphaltenes precipitating tests. The results showed that the above three types of comb-like polymeric pour point depressants(PPDs) could improve the flowability of the model waxy oil without asphaltenes(MO-1) to some extent and the POM showed the best flow improving efficiency on the MO-1: after adding 500 mg/kg POM, the pour point of the MO-1 decreased from 29 ℃ to 23 ℃ and yield stress reduced from 62.20 Pa to 83.35Pa. Comb-like polymers could significantly improve the flowability of model waxy oil with 0.3% asphaltenes(MO-2), and MO-2 showed the best flowability after the addition of 500 mg/kg POMA: the pour point and yield stress of MO-2 dropped to 3 ℃/1.27 Pa, respectively. Therefore, the comb-like polymeric PPDs and asphaltenes can synergistically improve the flowability of waxy oils and the introduction of aromatic pendants in the POM molecules can enhance the interaction of comb-like polymeric PPDs and asphaltenes, thus further increasing the synergistic effect of comb-like polymeric PPDs and asphaltenes.

    Synthesis of DOPO-based Cyclotriphosphazene Macromolecule Flame Retardant and Its Performance in Flame-retarded Epoxy Resin
    Minwen JIANG,Chenhui YIN,Sheng LI,Xiaoli LI
    2019, 40(12):  2615-2622.  doi:10.7503/cjcu20190257
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    A novel inorganic-organic hybrid macromolecule flame retardant, hexa-[4-(N-phenylamino-DOPO-methenyl)-phenoxyl]-cyclotriphosphazene(DOPO-PCP, DOPO=9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide) was synthesized successfully through three-step reactions including substitution, condensation and addition. The chemical structure of DOPO-PCP was characterized by Fourier transform infrared spectroscopy, 1H and 31P nuclear magnetic resonance spectroscopies. All the results conformed the functional groups of the DOPO-PCP designed. Then the thermal stability of DOPO-PCP, pure epoxy(DGEBA) and their composites was analyzed by thermogravimetric analysis, and the properties of flame-retarded cured epoxy were investigated by limited oxygen index(LOI), UL-94 vertical burning test and Cone calorimeter test. Among all the samples, P-1.3 passed UL-94 V-0 level test and its LOI value reached 36.2%, while the phosphorus content in it was only 1.3%. In cone calorimeter test, the heat release rate(HRR) and the smoke production rate(SPR) of P-1.3 went down obviously, meanwhile, its residual char mass increased significantly, demonstrating that DOPO-PCP was favored to flame-retarded DGEBA. Furthermore, the SEM images showed the excellent compatibility between the additives and DGEBA matrix, which made for the formation of the continuous char layer. The mapping photographs displayed the uniform distribution of phosphorus and nitrogen elements in intumescent char layer. As a result, DOPO-PCP was evaluated as a higher efficiency flame retardant by synergistic flame retardant mechanism in both gas phase and the solidification phase.