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10 April 2017, Volume 38 Issue 4

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Cover and Content of Chemical Journal of Chinese Universities Vol.38 No.4(2017)

2017, 38(4):  0-0. 

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Articles: Inorganic Chemistry

Preparation of High-Performance QD-encoded Magnetic Barcodes^†

LU Si, ZHANG Dingshengzi, LIU Bing, XU Hong, GU Hongchen

2017, 38(4):  509-516.  doi:10.7503/cjcu20160788

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The key element of the suspension array based multiplexed assays lies in the preparation of barcodes. Quantum dots(QDs) are ideal candidate fluorophores for optical encoding because of their outstanding fluorescent properties. By using chloroform/butanol mixed solution as CdSSe/ZnS QD reaction solvent, hydrophobic CdSSe/ZnS QDs were loaded onto the surface of magnetic polystyrene spheres via the modified layer-by-layer assembly proposed here. By the adjustment of QD concentration, high-performance CdSSe/ZnS QD encoded magnetic barcodes with different fluorescence intensity levels were successfully prepared. By comparing the CdSSe/ZnS QD encoded magnetic barcodes respectively prepared by using chloroform and chloroform/butanol mixed solution as reaction solvent, it was testified that the mixed solution helped to avoid the good QD solvent’s damage to the morphology of polymer spheres and facilitated the assembly of CdSSe/ZnS QDs. The prepared CdSSe/ZnS QD encoded magnetic barcodes demonstrated good dispersity in water, narrow distribution of fluorescence intensity and uniform morphology. This method paves a new way for simple, accurate and controllable preparation of QD-encoded barcodes with high encoding capacity.



Surface Modification of Au Nanorods and Their Interaction with H₂\begin{array}{c}{O_2}^{†}\end{array}

SHI Wen, SHAN Guiye, CHEN Yanwei

2017, 38(4):  517-521.  doi:10.7503/cjcu20160930

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The interaction conditions for H₂O₂ with Au nanorods(Au NRs) were investigated by changing the concentrations of H⁺ and Br^- in the reaction solution. Au NRs with positively surface were modified by poly(sodium-styrenesulfonate)(PSS) via electrostatic interaction to detect the effect of different ligands on the interaction between H₂O₂ and Au NRs. Different PSS concentration led to the corresponding change in localized surface plasmon resonance(LSPR) absorption peak of Au NRs. The results demonstrated that the increase of H⁺ concentration led to the increase of etching reaction ratio of Au NRs. The role of Br^- was depicted as stabilizing gold ions during the etching process of Au NRs. PSS molecules on Au NRs inhibited the etching process. In addition, the stability of PSS-modified Au NRs had great relation with the concentration of PSS molecules. When the amounts of PSS and hexadceyl trimethyl ammonium bromide(CTAB) were the same, the zeta potential was zero. Thus, Au NRs were unstable. With increasing the amount of PSS, the surface zeta potential became negatively and the stability of Au NRs increased.



Effect of Surface Mechanical Attrition Treatment on Bioactivity of Biomedical Titanium Alloy^†

HUANG Run, PAN Chengling*, ZHANG Lan

2017, 38(4):  522-529.  doi:10.7503/cjcu20160909

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Ti-25Nb-3Mo-3Zr-2Sn(TLM) titanium alloy was treated via surface mechanical attrition treatment(SMAT) method in this paper, subsequently the biomineralization, protein adsorption and osteoblast adhesion behaviors of treated and untreated titanium alloy samples were explored. The characteristic results by means of XRD, OM, TEM, AFM, XPS, SEM, EDX and contact angle experiment revealed that SMAT process did not alter the phase composition and grain size of TLM samples, however, it would obviously alter the surface roughness, topography, hydrophilicity and oxygen content of different chemical state of TLM samples. After immersed in the simulated body fluid solutions for 28 d, no new chemical compounds were detected on the untreated surface, nevertheless, hydroxyapatite precursor with a diameter of 1—2 μm and Ca/P ratio of 1.58 was observed on the treated surface. In vitro experimental results showed that the SMAT-treated sample could adsorb more proteins from the serum and osteoblasts exhibited much better adhesion condition on its surface. The SMAT-treated sample possessed superior biomineralization, protein adsorption and cellular adhesion-promoted capacity to the untreated sample, which was related with much larger surface roughness, better hydrophilicity and higher content of basic Ti—OH contained on the SMAT-treated surface.



In situ Solvothermal Synthesis, Structure and Luminescent Properties of a Compound with Copper(Ⅰ) Halides Chain^†

XIN Bingjing, LI Peng, LUO Lisha, XIA Tian, LI Guanghua

2017, 38(4):  530-532.  doi:10.7503/cjcu20160757

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A new compound formulated (C₁₀H₂₂N₂)₃[Cu₉I₁₄Br](C₁₀H₂₂N₂=N,N'-diethyl-1,4-diazabicyclo-[2.2.2]octane) was synthesized under solvothermal condition via in situ copper reduction and characterized by single crystal X-ray diffraction(XRD), elemental analysis, powder X-ray diffraction(PXRD) and Infrared spectroscopy. (C₁₀H₂₂N₂)₃[Cu₉I₁₄Br] crystallizes in monoclinic crystal system, space group C2/c with a=2.6233(5) nm, b=1.6299(3) nm, c=1.6707(3) nm, β=117.31(3)°, V=6.347(2) nm³. The title compound is constructed by organic cationic templates and anionic copper(Ⅰ) halide chains. The organic templates in this structure originated from the in situ N-alkylation reaction between N,N'-dimethyl-1,4-diazabicyclo[2.2.2]octane and alcohol solution. At ambient temperature, the title compound showed excellent luminescent property.



Synthesis, Structure and Thermochromic Properties of Al-doped Sm₃Fe₅O₁₂ Garnets^†

QI Hui, LIU Huanhuan, WANG Shan, YUAN Long, HOU Changmin

2017, 38(4):  535-540.  doi:10.7503/cjcu20160736

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A series of Sm₃Fe_5-xAl_xO₁₂(x=0, 0.1, 0.3, 0.5) samples was prepared via high-temperature solid state method and characterized by powder X-ray diffraction(XRD), scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(IR), X-ray photoelectron spectroscopy(XPS), UV-Vis-NIR spectroscopy. The results showed that all the samples are pure phase and Fe—O bonds are the main chromatic groups. The colors of all the samples(x=0, 0.1, 0.3, 0.5) turned from yellowish-green at room temperature to reddish brown at higher temperature(240 ℃).



Analytical Chemistry

Electrochemical Detection of Penicillin Based on Titanium Nitride Nanoparticles Carbon Paste Electrode^†

SUN Yiyan, LU Shanfu, WANG Haining, XIANG Yan

2017, 38(4):  541-546.  doi:10.7503/cjcu20160859

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A titanium nitride nanoparticles(TiN) modified carbon paste electrode was prepared to detect penicillin. The effects of the mass ratio of titanium nitride to graphite, electrode area, pH value and concentration of the buffer solution on the detection of penicillin were studied. With the optimized conditions, the electrode offered a minimum detection limit of 2×10^-5 mol/L and a linear dynamic range of 4×10^-5—3.2×10^-3 mol/L. Moreover, the detection mechanism was an adsorption action, which was revealed by the zeta potential and electrochemical impedance spectroscopy characterizations. Overall, the TiN modified carbon paste electrode shows good stability, high selectivity, excellent repeatability and a promising application in penicillin detection.



Sensitization for Determination of Iron by Microwave Plasma Torch Atomic Emission Spectrometry^†

LI Jiahui, ZHANG Qikai, ZHAO Shanlin, LI Ping

2017, 38(4):  547-553.  doi:10.7503/cjcu20160771

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The sensitizing effects of surfactant and lanthanum on the determination of iron by microwave plasma torch atomic emission spectrometry(MPT-AES) were studied to solve the low detection sensitivity and weak resistance to matrix interference under low-power working condition using argon as carrier gas and working gas. The operating conditions and the influence of coexisting elements on the determination of iron were investigated in detail. The results show that the non-ionic surfactant has an inhibiting effect on the determination of iron, while cationic surfactant and lanthanum chloride have a sensitizing effect, and the lanthanum salt shows the best effect. Lanthanum salts used as sensitizer can not only increase the sensitivity of MPT-AES determination of iron, but also increase the allowable amount of coexisting elements. When the concentration of La³⁺ in the test system is 0.500 mg/mL, the determination of iron could not be interfered by at least 40 times of zinc, 30 times of cobalt, 20 times of nickel and manganese, 15 times of calcium, 10 times of magnesium, copper and sodium. The emission intensity of iron increased up to 2.4 times, and the detection limit decreased from 27.5×10^-3 μg/mL to 8.5×10^-3 μg/mL when using lanthanum salts as sensitizer. The method was applied to the determination of iron in crude oil samples, and the measured results agree with that obtained by flame atomic absorption spectrometry.



Glucose Biosensor Based on Dy₂(MoO₄)₃-AuNPs Composite Nanomaterial^†

HUANG Haiping, YUE Yafeng, XU Liang, LÜ Lianlian, HU Yongmei

2017, 38(4):  554-560.  doi:10.7503/cjcu20160693

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Nanometer material of dysprosium molybdate[Dy₂(MoO₄)₃] was hydrothermally synthsized and employed for the fabrication of glucose biosensor by immobilizing glucose oxidase(GOD) on the Dy₂(MoO₄)₃-AuNPs composite nanomaterial. Dy₂(MoO₄)₃ and Dy₂(MoO₄)₃-AuNPs were characterized by transmission electron microscopy(TEM), UV-Vis spectrometry and energy-dispersive spectrometry(EDS). The electrochemical behavior of the biosensor was studied via the electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV). The experimental results indicated that Dy₂(MoO₄)₃-AuNPs nanocomposite material presented good biocompatibility for GOD and could accelerate the electron transfer rate between the immobilized GOD and the electrode. The biosensor showed a good linear relationship in the concentration range of glucose from 0.01 mmol/L to 1.0 mmol/L with the lowest detection limit of 3.33 μmol/L(S/N=3). Additionally, the biosensor owned satisfying stability and reproducibility.



Rapid Qualitative Analysis of Active Molecules in Tablets Using Microwave Plasma Torch Mass Spectrometry by the Regulation of Power^†

WANG Xinchen, YANG Meiling, ZHANG Xiaoping

2017, 38(4):  561-566.  doi:10.7503/cjcu20160686

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A microwave plasma torch mass spectrometry(MPT-MS) method was applied for the qualitative analysis of active ingredients in tinidazole and chlorpheniramine tablets. By changing the microwave power, both the parent ion and abundant fragment ions of the target were obtained in the full-scan mass spectra. These fragment ions were in accordance with the fragments from tandem mass spectrometry experiments, and even more abundant. Therefore, MPT source, with both hard ionization and soft ionization properties, could be used for the fast qualitative analysis of active ingredients in tablets, because it can obtain both parent and fragment ions in the full-scan mass spectrometry experiments. This rapid, accuracy, and no pollution MPT-MS method is useful for developing MPT coupled to a simple mass analyzer and realizing the miniaturization of mass spectrometer.



Studies of Electrochemical Polymerization of Thionine Using a Wavelength-interrogated Surface Plasmon Resonance Sensor^†

GONG Xiaoqing, WAN Xiumei, LU Danfeng, GAO Ran, CHENG Jin, QI Zhimei

2017, 38(4):  567-574.  doi:10.7503/cjcu20160681

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The electrochemical polymerization of thionine on gold layer was investigated by using a wavelength-interrogated surface plasmon resonance(SPR) sensor that operates at a fixed angle of incidence. The experimental results show that the resonant wavelength of SPR sensor linearly increases with increasing the number of voltammetry scanning cycles and the total redshift of resonance wavelength is 96.6 nm after 100 scanning cycles. The findings indicate that the film growth rate in every scanning cycle is constant and the poly(thionine) film formed after 100 cycles is ca. 71 nm thick based on the best fit of simulation results to the measured data. The poly(thionine) film in acidic buffer solution exhibits high electrochemical activity and its electrochemical reaction is diffusion-controlled. The resonant wavelength of SPR sensor reversibly changes in a voltammetry scanning cycle, indicating the complete reversibility of electrochemical oxidation-reduction reactions for the poly(thionine) film. Compared with the reduced poly(thionine) film, the oxidization of poly(thionine) film leads to a redshift of resonant wavelength, giving a sign that the refractive index of oxidized poly(thionine) film is higher than that of the reduced one.



PCA-LDA Analysis of Human and Canine Blood Based on Non-contact Raman Spectroscopy^†

ZHENG Xiangquan, LIAO Xin, XU Yi, HONG Mingjian

2017, 38(4):  575-582.  doi:10.7503/cjcu20160676

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Efficient and rapid non-destructive screening method for human and animal blood has great significance and practical prospects in export inspection and quarantine, forensic testing and other areas. By taking full advantages of Raman spectroscopy and combination of mathematical and statistical methods, species discriminant model for human blood and canine blood was established in this paper. First of all, the non-destructive Raman spectroscopy test for blood samples was focused. The factors which affected the non-destructive test were investigated in details, such as the material of anticoagulant tubes, the focus position and exposure time in Raman detecting and so on. Raman spectra of human and canine blood samples were obtained under the optimal conditions. The effective spectra were accumulated with 633 nm excitation in spectral range of 200—1800 cm^-1 with a 5 s integration time and 2 accumulating times. Laser power was selected approximately 8.85 mW. In view of the complexity of the blood sample composition and the high signal background of the Raman spectrum, the pretreatment method of wavelet denoising and piecewise polynomial baseline correction for the series of Raman spectra was proposed and solved effectively the recognition rate of the Raman spectrum. The model of multivariate statistical algorithm was established from the training data which set consisted of 30 spectra from human blood and 33 spectra from dog blood and the testing data which included five spectra from human blood and five spectra from dog blood by combining principal component analysis(PCA) with linear discriminant analysis(LDA) in MATLAB to identified the species of human and dog blood. The classification accuracy of proposed model for the calibration set and the blind test are 95.23% and 90.00%. Studies have shown that based on the non-contact method of testing blood samples Raman and PCA-LDA classification model has broad application value and prospect in the fields of import and export inspection and quarantine blood nondestructive identification.



Organic Chemistry

Design, Synthesis and Electroluminescence of Organic Conjugated Compounds Based on Pyrene-imidazole^†

LIU Yulong, LU Fang, LU Ping

2017, 38(4):  583-590.  doi:10.7503/cjcu20170049

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A series of organic fluorescent materials based on pyrene-imidazole was designed and synthesized by one-pot reactions. The compounds were thoroughly characterized by ¹H NMR and ¹³C NMR spectroscopy, mass spectroscopy and elemental analysis and corresponded well with their expected structures. The conjugation degree, spatial structure, the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO) energy levels are fine-tuned by the various substituents at C1 position of imidazole. They also increase the thermal stabilities of these pyrene-imidazole derivatives. These materials show potential applications in organic light-emitting diodes.



Design, Synthesis and Biological Evaluation of Novel O²-(2,4-Dinitrophenyl)diazeniumdiolates as Anti-tumor Agents^†

YAN Chang, ZOU Yu, FU Junjie, HUANG Zhangjian, ZHANG Dayong, ZHANG Yihua

2017, 38(4):  591-597.  doi:10.7503/cjcu20160798

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O²-(2,4-Dinitrophenyl)diazeniumdiolate(PABA/NO) possesses significant anticancer activity but poor stability. To search for new agents with stronger activity and better stability, PABA/NO was employed as a lead compound. A series of PABA/NO analogues was designed and synthesized with an appropriate secondary amine as the amine moiety in the diazeniumdiolate structure, and replacing the ester bond of the benzene ring with a carbon-nitrogen bond. The structures of the synthesized compounds were characterized by means of ¹H NMR, ¹³C NMR and HRMS. All the target compounds showed strong inhibitory effects against colon cancer HCT-116 cells to a varying extent. Compound 4h(IC₅₀=7.945±0.421 μmol/L) was the most potent against HCT-116 cells, superior to PABA/NO (IC₅₀=12.134±0.675 μmol/L). There was observed that a positive correlation existed between activity and NO release levels. The most active compound 4h released higher levels of NO in colon cancer cells than that in the normal ones. In addition, compound 4h showed better stability in plasma than PABA/NO. These results suggested compound 4h might be a promising anticancer agent, and worthy of further study.



Synthesis, Characterization and Tribological Properties of Imidazol Cheat Boron Ionic Liquids with Different Alkyl Length^†

ZHANG Yunxiao, SHANG Wangji, SUN Liwen, LIU Dan, TONG Dingyi, CAI Tao, LIU Shenggao

2017, 38(4):  598-605.  doi:10.7503/cjcu20160684

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Four environmental-friendly ionic liquids containing imidazol cations with different alkyl chain lengths and bis(salicylato)borate anion were synthesized. Their structures were characterized by NMR, ICP-OES and tribo-performance was studied on four-ball machine and SEM-EDX as well. Tribological properties are largely influenced by alkyl chain lengths. C_nMImBScB(n=2,4,6,8) have excellent friction reducing properties, in particular, the coefficient of friction and wear scar diameter lubricated by PEG200 under 392N reduce 58.46% and 20.5%, respectively, when mass fraction of 2% C₈MImBScB is introduced. The elemental mapping of worn surfaces reveal that the formation of cheat boron ionic liquids constitutes a tribo-chemical thin film, which not only protect the contact surface against the wear at some extent but also reduces the friction significantly.



Physical Chemistry

Preparation of Rh/Al₂O₃-Cr₂O₃ Monolithic Catalysts for Dichloromethane Combustion^†

CHEN Wenya, ZHU Li, HE Jun, XIE Yunlong, LU Jiqing, LUO Mengfei

2017, 38(4):  606-612.  doi:10.7503/cjcu20160843

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A series of Rh catalysts supported on Al₂O₃ powder was prepared by impregnation method. Then a series of Rh/Al₂O₃-Cr₂O₃ monolithic catalysts was prepared by coating method, different proportions of Rh/Al₂O₃, Cr₂O₃ and aluminum gel were mixed into a homogeneous slurry, and then was coated onto the cordierite honeycomb ceramic. These catalysts with different Rh contents were tested for catalytic combustion of dichloromethane. It was found that the 0.4 Rh/Al₂O₃-Cr₂O₃(Rh contents: 0.4 g/L) had the highest activity and no chlorine-containing by-products were formed. The catalysts were characterized by various techniques such as XRD, H₂-TPR, NH₃-TPD and BET. The results showed that the addition of Rh can improve the surface acidity and redox performance of the catalyst, and further improve the activity of the catalyst. It was believed that the activity of the catalyst was closely related to its reducibility and surface acidity. Moreover, the addition of Cr₂O₃ is beneficial to the further oxidation of CH₃Cl intermediate and thus improve the selectivity.



Theoretical Studies on the Reaction Mechanism of Criegee Intermediates RCHOO(R=H, CH₃) with NCO Radical^†

MA Qian, WANG Weina, ZHAO Qiangli, LIU Fengyi, WANG Wenliang

2017, 38(4):  613-621.  doi:10.7503/cjcu20160803

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A comprehensive theoretical study about the reaction of RCHOO(R=H, CH₃) with NCO was performed at the CCSD(T)/aug-cc-pVTZ//B3LYP/6-311+G(2df,2p) level. The rate coefficients for the dominant reaction channels were determined at 298—500 K via conventional transition state theory(TST) with a Eckart tunneling. The results show that the detailed mechanism mainly includes addition, oxidation and hydrogen abstraction reactions. N and O atoms of the NCO radical can react to RCHOO(R=H and CH₃) in each reaction mode. Moreover, the end O atom of NCO addition to RCHOO(R=H and CH₃) α-C is favored for the addition reaction, while the reactions involving the end N atom of NCO is advantaged in both oxidation and hydrogen abstraction. The methyl substituents in the CH₂OO produce an increase of the reactivity. Anti-CH₃CHOO shows a higher reactivity than syn-CH₃CHOO towards addition and oxidation reaction, but for the hydrogen abstraction, syn-CH₃CHOO is significantly more reactive than anti-CH₃CHOO. The contribution of anti-CH₃CHOO to the overall rate constant is greater than that of syn-CH₃CHOO, and the total rate constant satisfies a strong negative temperature effect.



Adsorption Characteristics of Different Forms of Ofloxacin to Attapulgite^†

QUAN Yao, BI Erping

2017, 38(4):  622-630.  doi:10.7503/cjcu20160773

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By controlling the pH of reaction system, the adsorption characteristics of different forms of ofloxacin(i. e., OFL^±, OFL⁺, and OFL^-) to attapulgite(ATP) were investigated. The experimental results showed that exchanging with Ca²⁺ and Mg²⁺ on the surface of ATP was the main sorption mechanism for OFL⁺. When OFL⁺ adsorption quantity increased, there will be little amount of hydrogen bonding between OFL⁺ and ATP surface. OFL^± and OFL^- can form surface complexation with iron/aluminum oxide on the surface of ATP. Meanwhile, both OFL^± and OFL^- can form complexes with cations(Ca²⁺, Mg²⁺) dissolved from ATP and then adsorbed on ATP by electrostatic attraction. Because of the lower electronegativity of Ca than Mg, [Ca²⁺-OFL]⁺ cannot exist stably in neutral to weakly alkaline(e. g., pH=7.10—7.70) solution, which results in the situation that OFL^± exchange with Ca²⁺ but form complexes with Mg²⁺ then adsorbed to ATP by electrostatic attraction. When OFL^- was the main form in solution(pH=9.00—10.00), both Ca²⁺ and Mg²⁺ can form complexes with OFL^- and then adsorbed to ATP by electrostatic attraction.



Study on Robust Icephobicity of Tape Surface^†

CHEN Yu, WANG Lei, WANG Bo

2017, 38(4):  631-635.  doi:10.7503/cjcu20160766

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Gluing polymethyl methacrylate(PMMA) microspheres on the tape and planting ZnO nanorods on the microspheres with crystal growth method, we got the microsphere/nanorods topographies, which is characterized as flexibility, larger size, superhydrophobicity and icephobicity in low temperature. The liquid water droplet could suspend on the surface and realize to delay icing performances. The interface of solid/liquid changes little before and after the icing/melting cycle, which indicates the robust stability. This functional anti-icing film composed with tape and PMMA has potential application in the fields such as wind power, high voltage cable and fridge.



Facile Cyclohexane-mediated Hydrothermal Synthesis of Modified δ-MnO₂ with Enhanced Fenton-like Catalytic Activity^†

MA Zichuan, LI Junshu, XING Shengtao

2017, 38(4):  636-641.  doi:10.7503/cjcu20160731

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Unmodified δ-MnO₂(CHM-0) and modified δ-MnO₂(CHM-2, CHM-5 and CHM-10) were prepared via a hydrothermal method employing the reaction between KMnO₄ and different amounts(0, 2, 5 or 10 mL) of cyclohexane. The products were characterized by X-ray diffraction(XRD), field emission scanning electron microscope(FESEM), transmission electron microscopy(TEM) and nitrogen adsorption-desorption measurements. The oxidation products of cyclohexane in the hydrothermal process were identified by gas chromatography-mass spectrometry(GC-MS). Their Fenton-like activity and adsorption capacity for methylene blue(MB) were investigated. The effect of radical scavengers on the degradation of MB was also studied. The results indicate that the adsorption capacity of the modified samples increased with increasing the amount of cyclohexane, and CHM-5 exhibited the highest catalytic activity. The addition of cyclohexane could modify the morphology and crystallinity of δ-MnO₂, and its oxidation products consisted of acetone, cyclohexanol and cyclohexanone. The surface area of CHM-5 was 148.7 m²/g, much larger than 15.9 m²/g of CHM-0. Hydroxyl radicals were the main active species.



Applications of Carbon Fiber Ultra-microelectrode and Powder Microelectrode in Exploring Influences of Non-aqueous Solvents and Cathode Materials on ORR and OER^†

LI Weilun, YAO Ying, ZHANG Cunzhong

2017, 38(4):  642-652.  doi:10.7503/cjcu20160727

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Carbon fiber ultra-microelectrode was used to study the electrochemical reactions of O₂ in dimethyl sulfoxide, acetonitrile and tetraethylene glycol dimethyl ether. The results suggested that in tetrabutyl-ammonium-ion(TBA⁺)-containing electrolytes, the electrochemical reactions were reversible reactions of one-electron transfer; while in lithium-ion(Li⁺)-containing electrolyte, multiple-electrons transfer occurred during the oxygen reduction reaction(ORR) and oxygen evolution reaction(OER). Powder microelectrodes of super P and conductive acetylene black were used as working electrodes to conduct electrochemical experiments. The results showed the ORRs were similar, but the OER had differences on these two materials. Besides, Tafel analyses indicated that during the ORR, one-electron transfer always took place at first whether in different non-aqueous solvents or on different cathodes.



Performance of WO₃ Modified Graphene Supported Pd Nanocatalysts for Formic Acid Electro-oxidation^†

JIN Yanxian, JIA Wenping, LIANG Danxia, LI Fang, LI Rongrong, ZHENG Mengmeng, GAO Weiyi, NI Jiamin, HU Jiajie, WU Tinghua

2017, 38(4):  653-659.  doi:10.7503/cjcu20160692

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The composites WO₃-GO were prepared by the modification of WO₃ crystal particles onto the surface of graphene oxide(GO), Pd/WO₃-RGO catalysts were prepared by using potassium borohydride as the reducing agent. The performances of the catalysts and the effect of different contents of WO₃ on the catalytic activity were investigated. The Pd/WO₃-RGO catalysts showed significantly enhanced electrocatalytic performances for formic acid oxidation. The peak current density on the best catalyst Pd/20%WO₃-RGO catalyst was 2.5 times that on Pd/RGO catalyst. And more importantly, Pd/WO₃-RGO catalysts showed improved stability and excellent tolerance to CO poisoning. According to XRD, TEM and HRTEM results, Pd/WO₃-RGO catalysts are made of monoclinic WO₃, face centered cubic palladium crystal particles and graphene. WO₃ particles are most likely to be covered or overlapped with Pd particles and Pd nanoparticles have a uniform distribution. The enhanced catalytic activity of Pd/WO₃-RGO can be ascribed to the interaction between Pd and WO₃.



Polymer Chemistry

Intramolecular Reaction in Self-condensing Vinyl Polymerization System with Solvent Effect^†

WANG Yunming, CHANG Peiyang, GU Fang, WANG Haijun

2017, 38(4):  660-668.  doi:10.7503/cjcu20160824

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We present the effect of intramolecular reaction on the average properties of hyperbranched polymers formed in the self-condensing vinyl polymerization system by the method of Monte Carlo simulation. A model to specify the generations of all units in a branched polymer was proposed to model intramolecular reaction, from which a set of kinetic differential equations was given to describe the growth of various polymers. The simulation was performed by means of the intermolecular and intramolecular reaction rates under different solvent conditions. As a result, the number of treelike and cyclic polymers, the size distribution of rings and weight-average molecular weights were obtained, by which the effect of cyclization on the average properties of polymers was discussed. Furthermore, it is shown that cyclization depends on the cooperation of monomer concentration and solvent quality, where monomer concentration plays a key role in intramolecular reaction, while solvent quality becomes significant only at a high concentration. It is expected that the present study is helpful to design the related materials.



Adsorption Behavior of Hydrophilic Luffa Sponges to Heavy Metal Ions in Water System^†

LIU Zhi, LI Bingrui, PAN Yanxiong, SHI Kai, WANG Weicai, PENG Chao, WANG Zhe, JI Xiangling

2017, 38(4):  669-677.  doi:10.7503/cjcu20160760

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A kind of partially hydrolyzed polyacrylamidehydrophilic luffa sponges [luffa-g-(PAM-co-PAANa)] was prepared through grafting polymerization, and the grafting percentage reached up to 161.3%. In typical Cu²⁺ and Pb²⁺ systems, the adsorption behavior of hydrophilic luffa sponges was studied. In a single metal ion system, the adsorption kinetics fits well with the pseudo-second-order kinetic equation. The adsorption capacities increase with the grafting percentage and pH value. In particular, the highest adsorption capacities can reach up to 647 mg/g for Cu²⁺ and 887 mg/g for Pb²⁺. Hydrophilic sample can be regenerated through a simple route and reused in eight adsorption-desorption cycles without any significant loss in the adsorption capacity. The adsorption mechanism was discussed. Definitely, this kind of hydrophilic luffa sponges as effective adsorbent, exhibits potential application in the purification of polluted water system.



Self-assembly Behavior of Amphiphilic Janus Particles in the Acting Process of Breath Figure Method^†

YANG Pinghui, ZHU Jiafeng, SUN Wei, ZHOU Wanrong

2017, 38(4):  678-685.  doi:10.7503/cjcu20160711

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Breath figure(BF) method is a dynamic templating method for surface patterning of polymeric materials. The BF process has been extensively studied as a novel methodology to achieve surface patterning via self-assembly. During the evaporation of the solvent, functional buliding blocks added into the casting solution such as nanoparticles, block copolymers and other components containing hydrophilic parts could be able to spontaneously migrate onto the water/oil interfaces formed between templating water droplets and casting solution during the BF process. As a result, functionalization and modification of the obtained patterned surfaces on selective areas could be achieved at the time when matrices of patterned surfaces are formed. By employing the particles in BF method, the porous film with pore arrays selectively decorated with particles can be fabricated. Based on the combination of interfacial self-assembly of particles and self-assembly process of BF, amphiphilic Janus particles were employed in the breath figures method. Amphiphilic Janus silica particles were prepared by selective chemical treatment on the particle “colloidosomes”. Janus particles enriching the patterned pores present unique assembling characteristics which are much different from previously reported cases with homogeneous particles. The experimental results indicate that Janus particles show optimized assembling morphology when they are involved in the interfacial self-assembly process of BF. By employing Janus particles, a trade-off of the ordering of the honeycomb-structured pore arrays and the density of decorated particles was also achieved. With lower concentration of particles being used, Janus particles show quite different assembling behavior from their homogeneous counterparts. It opens an attractive route to produce functional hierarchically patterned materials by, for example, loading the biological Janus particles for single-cell cultures or catalytic Janus particles for micro-chemical reactors.



Fabrication of TiO₂-GO/PI Mixed Matrix Membranes by In-situ Polymerization and Their Gas Permeation Property^†

YANG Caihong, MAN Chunli, XUE Wanlei, WANG Ting, CHEN Di, CHEN Qian, WU Liguang

2017, 38(4):  686-693.  doi:10.7503/cjcu20160678

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Titanium dioxide-graphene oxide(TiO₂-GO) nanocomposites were synthesized by impregnation-reduction method using tetrabutyl titanate(C₁₆H₃₆O₄Ti) as the source of TiO₂, then TiO₂-GO/polyimide(TiO₂-GO/PI) mixed matrix membranes were fabricated via in-situ polymerization with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)/4,4'-oxydianiline(ODA)/TiO₂-GO. The structures of TiO₂-GO nanocomposites and TiO₂-GO/PI mixed matrix membranes were characterized by Fourier transform infrared spectroscopy(FTIR), Raman spectroscopy and transmission electron microscopy(TEM), scanning electron microscope(SEM), thermo-gravimetric analysis(TGA) and zeta potential instrument. The effects of TiO₂-doping on the structure of TiO₂-GO nanocomposites and TiO₂-GO/PI mixed matrix membranes were discussed, and the gas permeation properties of the mixed matrix membranes were measured. The results reveal that TiO₂ nanoparticles are impregnated uniformly in GO nanosheets, the dope of TiO₂ would slightly destroy the structure of GO, and the disorder degree of GO structure increased. But the dope of TiO₂ which was helpful to improve the dispersion of TiO₂-GO nanocomposite in the mixed matrix membrane, thus enhance the gas permeation properties of the mixed matrix membrane. However, the excess of TiO₂-doping would lead to the aggregation of TiO₂ particles on the GO surface, which depressed the gas permeation properties of the mixed matrix membrane. When the mass fraction of TiO₂-doping reached 15% in TiO₂-GO nanocomposite, the mixed matrix membrane demonstrated good CO₂ permeability and CO₂/N₂ permeation selectivity, and CO₂ permeability was 360 Barrer, and CO₂/N₂ permeation selectivity reached 31.



Electrochromic Properties of Polyaniline Films on Graphene-ITO Composite Electrode^†

LÜ Xiaojing, YU Pengfei, OUYANG Mi, QIAN Liang, YAN Shuanma, JIN Xiaoqiang, ZHANG Cheng

2017, 38(4):  694-700.  doi:10.7503/cjcu20160636

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Graphene oxide(GO) aqueous solution was synthesized by modified Hummers method. Graphites reacted with concentrated sulfuric acid, potassium persulfate and phosphorus pentoxide to get strong oxidized products, then reacted with concentrated sulfuric acid, sodium nitrate and potassium permanganate. GO solution was obtained through the foaming of hydrogen peroxide, pickling and ultrasonic. After the reduction of metal copper and substrate transformation process, GO-indium tin oxide(ITO) composite electrode was prepared. Then, polyaniline(PANI) film was prepared on the composite electrode by electropolymerization technique and further characterized. Compared to that on ITO electrode, PANI film on GO-ITO composite electrode showed a more homogeneous and uniform nanoparticle morphology and better film-forming character, providing larger interface area between the polymer and electrolyte and more transport channel for counterions. The result showed that PANI film exhibited higher optical contrast with increasing by 13% at 700 nm, faster switching speed with reducing by 2.6 s, high coloration efficiency of 169.6 cm²/C and still remained the original good electrochemical stability. In summary, GO-ITO composite electrode can effectively improve electrochromic performance, endowing the potential applications on electrochromic materials and devices.