Table of Content

10 July 2015, Volume 36 Issue 7

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Letter

Ion Transport in DNA Superstructure Modified Diamond-shaped Nanopores^†

JIANG Yanan, KANG Qian, GUO Wei, JIANG Lei

2015, 36(7):  1243-1245.  doi:10.7503/cjcu20150267

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Inspired by the biological ion channels, DNA supersandwich structures were self-assembled in diamond-shaped mica nanopores, forming highly efficient gate-like nanofluidic switch. Through asymmetric DNA modification in the mica nanopores, rectified ion transport property was observed. The results revealed that DNA, the flexible biological molecules, can also be used to build nanofluidic devices for gating and rectification function in solid-state nanopores with parallel tetrahedron structures.



Articles: Inorganic Chemistry

Oxygen Permeation Property and Structural Stabiltiy of La-doped BaCo_0.88Nb_0.12O_3-δ Membranes in CO₂ Atmosphere^†

ZHANG Xingxing, WU Chengzhang, ZHOU Jianfang, YANG Gonghui, LIU Yinhe, ZHANG Yuwen, DING Weizhong

2015, 36(7):  1246-1253.  doi:10.7503/cjcu20141082

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La-doped BaCo_0.88Nb_0.12O_3-δ(BLCN-x, x represents the molar ratio of La) perovskite membranes were prepared by solid phase reaction. The structrural stability of membranes was analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM), thermogravimetric(TG) analysis and temperature programmed desorption-mass spectrography(TPD-MS) methods. The results indicated that the CO₂ tolerance properties of BLCN-x membranes were improved markedly with the increase of La content. Specially, the diffraction peaks of witherite can’t be observed for the membranes with a La content higher than 0.5, whatever the membranes were calcined or conducted the oxygen permeation measurement with pure CO₂ sweeping. The initial oxygen permeation flux of BLCN-x membranes would be reduced with the doping of La, however, the oxygen flux of BLCN-x membranes swept by CO₂ was more stable with the increase of La content. Particularly, the oxygen flux of BLCN-0.5 membrane is about 0.46 mL·cm^-2·min^-1 after pure CO₂ sweeping for 10 h. The better structural stability and CO₂ tolerance properties of BLCN-x membranes with higher La content are due to more appropriate Goldschmidt tolerance factor and the enhanced average metal-oxygen bond energy.



Mechanism of the Interaction Between a Phosphorus-containing Tripod Ligand Europium(Ⅲ) Complex and Bovine Serum Albumin^†

YANG Shuilan, SONG Pan, SHE Wenjie, YANG Tianlin

2015, 36(7):  1254-1263.  doi:10.7503/cjcu20141088

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Under the simulated physiological condition(Tris-HCl buffer, pH=7.3), the interaction of N-bis(benzene-diamino formyl)methyl phosphate europium(Ⅲ) complex[Eu(pic)₃L] and bovine serum albumin(BSA) was studied by fluorescence spectrometry, cyclic voltammetry and UV spectroscopy. The results indicate that no fluorescent compound Eu(pic)₃L-BSA(ratio 1∶1) is formed and the complex can markedly quench the intrinsic fluorescence of BSA via a static quenching process. The binding constant(K) and binding site number(n) were calculated according to the double logarithm regression equation under different temperatures, the thermodynamic parameters show that the main force between complex and BSA is hydrogen bonding and van der Waals forces. The complex and BSA may have dipole-dipole non-radiation energy transfer accor-ding to the Foster’s theory of dipole-dipole non-radiation energy transfer. The effects of metal ions Fe³⁺ and Cu²⁺on the interactions between BSA and complex were investigated, and the results show that Fe³⁺ and Cu²⁺ may play “ion bridge” role in complex and BSA, making the stability of Eu(pic)₃L-BSA enhanced. Cyclic voltammetry results indicate that non-electric activity compound Eu(pic)₃L-BSA is formed, which lower the free complex concentration in the solution.



Analytical Chemistry

Synthesis of Photoluminescence Ag₂Te Quantum Dots in Second Near-infrared Window^†

WANG Jiamei, ZHU Chunnan, ZHU Dongliang, TIAN Zhiquan, LIN Yi, PANG Daiwen

2015, 36(7):  1264-1268.  doi:10.7503/cjcu20150306

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Ag₂Te quantum dots(QDs) with an emission in the second near-infrared window were synthesized by tuning the ratio of Ag precursor to Te precursor using 1-octanethiol as a ligand. The products were characterized by transmission electron microscopy(TEM), X-ray powder diffraction(XRD), X-ray photoelectron spectroscopy(XPS), UV-Vis-NIR absorption spectroscopy and the corresponding photoluminescence(PL) spectroscopy. The as-prepared Ag₂Te QDs have a narrow size distribution, good dispersibility with fluorescence emission at 1320 nm and a PL quantum yield of 4.2%.



Colorimetric Detection of Dopamine Based on Silver Nanoparticles^†

FENG Juanjuan, ZHAO Yiman, WANG Haiyan

2015, 36(7):  1269-1274.  doi:10.7503/cjcu20150273

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A simple and sensitive colorimetric method for the detection of dopamine was proposed based on the redox reaction between silver ion and dopamine, which was catalyzed by silver nanoparticles(AgNPs), causing the color change. The increase of dopamine concentration led to red shift of absorption peak and increase of the absorbance. Meanwhile, the color of the solution changed from pale yellow and deep yellow. Under optimal conditions, a linear range of 0.05—16 μmol/L between the absorbance and dopamine concentration and a detection limit of 0.04 μmol/L was obtained. The proposed method was sensitive, simple, low-cost and selective, which could be applied for the detection of dopamine in human serum.



Comparative Analysis of O-glycans from Human Hepatocellular Carcinoma HepG2 and Normal Liver Cells L02^†

PAN Liying, GU Xiao, WANG Chengjian, QIANG Shan, HUANG Linjuan, ZHANG Ying, WANG Zhongfu

2015, 36(7):  1275-1281.  doi:10.7503/cjcu20150062

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HepG2(a primary hepatocellular carcinoma cell line) and L02(ones derived from normal liver tissue) cells were chosen as model cell lines for research. The O-glycans of the total proteins extracted from HepG2 and L02 cells were released by Carlson reductive β-elimination. The released O-glycans previously purified by Dowex 50 WX8-400 cation exchange resin and C₁₈ cartridges were identified by electrospray ionization mass spectrometry(ESI-MS)and MS/MS. For comparision studies, β-cyclodextrin was used as the internal standard for relative quantitative analysis of the O-glycans derived from HepG2 and L02 cells by MS. As results, 10 O-glycans were observed in HepG2 cell line and 9 O-glycans were detected in L02 cell line. Moreover, 9 O-glycans were observed in both HepG2 and L02 cells, wherears 1 truncated O-glycan assigned as H1A1(NeuAc-GalNAc, sialyl Tn antigen, ubiquitous in cancer cells), was only found in HepG2 cells. t-Test results show that 5 and 2 O-glycans in HepG2 cells have significant differences(P<0.01 and P<0.05, recpectively), when compared to those of L02 cells. Our studies show methodological significance in structural investigation of O-glycans expressed in hepatocellular carcinoma and early biomarker discovery in clinical diagnose.



Simultaneous Detection of Ascorbic Acid, Dopamine, Uric Acid and Tryptophan on the PEI-graphene Modified Electrode^†

LI Chong, JIA Liping, MA Rongna, JIA Wenli, WANG Huaisheng, YANG Haitao, GUO Aixiang

2015, 36(7):  1282-1290.  doi:10.7503/cjcu20141143

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Ascorbic acid(AA), dopamine(DA), uric acid(UA) and tryptophan(Trp) are considered as crucial small biomolecules for physiological processes in human metabolism. Abnormal levels of these species will lead to the occurrence of some diseases and disorders. In this paper, polyethyleneimine(PEI) covalent functionalized graphene(PEI-G) was used to modify glassy carbon electrode and applied for the simultaneous and sensitive determination of the four molecules.The PEI-G nanocomposite was characterized by fourier-transform infrared spectroscopy(FTIR), ultraviolet-visible(UV-Vis), X-ray powder diffraction(XRD) and transmission electron microscopy(TEM). The electrochemical behaviors of AA, DA, UA and Trp on PEI-G modified electrode were studied in detail. And the optimal experimental conditions for the simultaneous determination of AA, DA, UA and Trp were explored. The results showed that the oxidation peaks of the four species could be well separated and the peak to peak separations were 298 mV(AA-DA), 130 mV(DA-UA) and 350 mV(UA-Trp), respectively. The linear response ranges for the simultaneous detection of AA, DA, UA and Trp were 50—5800 μmol/L, 30—2570 μmol/L, 0.05—400 μmol/L and 6—1000 μmol/L, with the detection limits of 16.67 μmol/L, 10 μmol/L, 0.017 μmol/L and 2 μmol/L, respectively. The proposed method provides a promising strategy for the simultaneous detection of these species in practical application.



Organic Chemistry

Design, Synthesis and Biological Activity of Novel Sulfonylurea Derivatives Containing Dimethoxymethyl-substituted Pyrimidine Moiety^†

CHEN Wei, WEI Wei, LIU Ming, HUA Xuewen, LI Yuxin, LI Yonghong, ZHANG Xiao, LI Zhengming

2015, 36(7):  1291-1297.  doi:10.7503/cjcu20150100

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Sulfonylureas(SUs) as one of the most active herbicides targeted on acetolactate synthase(ALS). ALS was found not only in plants, but also in fungi and bacteria. In order to study the multi-biological activity of sulfonylurea(SU), a series of novel SU derivatives containing dimethoxymethyl pyrimidine moiety was designed, synthesized according to bioisosteric principles. The bioassay results indicated that the title compounds exhibited favorable herbicidal activity. Compounds 6a and 6g showed 100% pre-emergence inhibition activity against Brassica napus at the dosage of 75 g/ha, which were near to that of Monosulfuron and Chlorsulfuron(100%). In addtion, some of the title compounds also exhibited moderate antifungal activity. Compounds 6i and 6o showed over 80% antifungal activity against three fungi in vitro at the concentration of 50 mg/L, and closed to that of Chlorothalonil and Carbendazim. It provided useful information for designing new SU with highly herbicidal activity and fungicidal activity.



Syntheses of Carboxyl Functionalized Benzotriazol-based Ionic Liquids and Their Application in Extraction-oxidative Desulfurization^†

XUE Fei, MA Rong, SUN Yadong, ABDUKADERA Ablimit, ZHANG Yonghong, LIU Chenjiang

2015, 36(7):  1298-1303.  doi:10.7503/cjcu20150192

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A new class of ionic liquids(ILs) 1-alkyl-3-carboxymethyl double trifluoromethanesulfonimide was synthesized and characterized. Ionic liquids and hydrogen peroxide were tested in extraction-oxidative desulfurization system, and the sulphur removal efficiency of S-compounds in the model oil was investigated. The results showed that the 1-butyl-3-carboxymethyl double trifluoromethanesulfonimide salt([C₂O₂BBTA][NTf₂]) was both extractant and catalyst, n(H₂O₂)∶n(S)=2.5∶1, m(Model oil)∶m(Ionic liquid)=5∶1, at 75 ℃ for 1 h. The ratios of desulfurization to the model oil of dibenzothiophene(DBT), benzothiophene(BT) and 4,6-dimethyldibenzothiophene(4,6-DMDBT) reached 98.3%, 98.3% and 96.6%. Ionic liquid can be recycled for 10 times with an unnoticeable decrease in desulfurization activity. The method can realize deep desulfurization the depth have the advantages of both simple operation and mild reaction condition.



Artificial Hydrolase Based on Short Peptides Self- and Co-assembly Nanofiber^†

LÜ Yuqi, WANG Mengfan, QI Wei, SU Rongxin, HE Zhimin

2015, 36(7):  1304-1309.  doi:10.7503/cjcu20150161

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The catalytic triad(Ser/His/Asp) of natural hydrolase were introduced into the peptide segment of 9-fluorenylmethoxycarbonyl-diphenylalanine(Fmoc-FF), 9-fluorenylmethoxycarbonyl-phenylalanine-phenylalanine-histidine(Fmoc-FFH), 9-fluorenylmethoxycarbonyl-phenylalanine-phenylalanine-serine(Fmoc-FFS) and 9-fluorenylmethoxycarbonyl-phenylalanine-phenylalanine-aspartate(Fmoc-FFD) were designed to construct the artificial hydrolase. Based on the self-assembly and co-assembly of Fmoc-peptides, a series of supramole-cular nanofibers built from the self-assembly of Fmoc-FFH(SA-H), self-assembly of Fmoc-FFS(SA-S), self-assembly of Fmoc-FFD(SA-D), co-assembly of Fmoc-FFH and Fmoc-FFS(CoA-HS), co-assembly of Fmoc-FFH and Fmoc-FFD(CoA-HD), co-assembly of Fmoc-FFD and Fmoc-FFS(CoA-DS), co-assembly of Fmoc-FFH, Fmoc-FFD and Fmoc-FFS(CoA-HDS) were obtained as artificial hydrolases. SA-H exhibited the highest hydrolysis activity for p-nitrophenyl acetate(PNPA). It was found that the well-ordered structure of nanofiber is important for catalytic activity, and the β-sheet structure come from the week interactions between Fmoc groups. The kinetics behavior, optimum temperature and pH studies showed the typical enzymatic cha-racteristics of artificial hydrolase as that of natural enzyme. In addition, metal ions Ca²⁺, Ba²⁺ can activate the artificial hydrolase, whereas Mg²⁺, Ni²⁺, Co²⁺, Cu²⁺, Zn²⁺ inhibit the activity.



Inhibitory Effect of Phenolic Compounds on Amyloid Fibrillation of Insulin^†

ZHANG Yujie, CAO Na, ZENG Chengming

2015, 36(7):  1310-1314.  doi:10.7503/cjcu20150087

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More than 20 human diseases are considered to be associated with amyloid fibrillation in polypeptides. Polyphenolic compounds have been demonstrated to disrupt amyloid structures and attenuate cytotoxicity of amyloid fibrils. In the present study, the inhibitory effects of four phenolic compounds on amyloid formation were investigated using bovine insulin as a model peptide. The results indicated that catechol and hydroquinone inhibited insulin fibrillation and bonded to the peptide chains with quinone moieties, showing a similar effect to benzoquinone. In contrast, phenol and resorcinol did not modify insulin with a quinone moiety, showing no effect on amyloid fibrillation. Furthermore, catechol and hydroquinone were less effective as an inhibitor of insulin fibrillation under anaerobic conditions, suggested that the formation of quinone intermediates via oxidation and subsequently transform insulin into quinopeptide were prerequisites for a phenolic compound to inhibit amyloid fibrillation. The results show that quinone intermediates are the active form for phenolic compounds to inhibit insulin amyloid fibrillation.



Synthesis and Biological Activities of 1,2,4-Triazole Schiff Bases Containing Pyrazole Rings^†

WANG Zijian, SUN Xiaohong, LIU Yuanfa, CHEN Bang, SHEN Shengqiang, JIN Ruyi, MA Haixia

2015, 36(7):  1315-1320.  doi:10.7503/cjcu20150036

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An important class of compounds formed by 1,2,4-triazole and its derivatives were reported to exhibit a broad spectrum of biological activities. And pyrazole derivatives usually have antifungal, anticancer and herbicidal activities. The compounds containing 1,2,4-triazole and pyrazole would provide better biological activities simultaneously according biological activity of the superposition principle. In the present work, a series of novel 1,2,4-triazole Schiff bases containing pyrazole rings was synthesized by multistep reactions. Their structures were characterized by IR, ¹H NMR, ¹³C NMR, HRMS, elemental analyses and X-ray diffraction techniques. The biological activities of the target compounds for the against four vegetable pathogens containing Gibberll nicotiancola, Gibberlla saubinetii, Fusarium oxysporium f. sp. niveum and Pythium solani were evaluated. The preliminary results indicated that most of the compounds exhibit relatively good antifungal activities, especially compounds G9, G10 and G15 showed better biological activity than triazolone.



Highly Efficient Preparation of Resorufin-β-D-glucuronide^†

WANG Xinxin, LÜ Xia, GE Guangbo, FENG Lei, XIN Hong, LI Yaoguang, CAO Yunfeng, HAN Guanying, GUO Bin

2015, 36(7):  1321-1327.  doi:10.7503/cjcu20141107

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Resorufin-β-O-glucuronide(REG) is a substrate of the β-glucuronidase enzyme which exhibited almost no fluorescence, upon addition of β-glucuronidase a high fluorescent compound resorufin will be released. Resorufin, is a fluorescent compound possessing good optical properties. On the basis of the off-on type fluorescent reaction, REG can be served as the good fluorescent substrate of β-glucuronidase. However, commercial available REG is rather expensive due to the difficulty for preparation of REG and the studies on REG are very limited. This study aimed to adopt the mild biosynthesis approach to efficiently prepare REG, based on resorufin can be extensively metabolized to REG by UDP-glucuronosyltransferases(UGTs). REG was prepared using resorufin as the starting material and liver microsomes from cynomolgus monkeys(CyLM) as the enzyme source. Resorufin(RE, 100 μmol/L) was incubated in Tris-HCl(50 mmol/L, pH=7.4, with 1% DMSO) with CyLM(0.5 mg/mL) at 37 ℃ for 4 h. After the optimization of the incubation conditions, the conversion of REG was more than 80%. A unique solid-phase extraction column(SPE) packed with C18WAX was used to enrich and purify the product REG with high yield. The product was then identified by both LC-MS and NMR techniques. Finally, a high throughput screening method for β-glucuronidase inhibitors was well established, based on the accurate kinetic parameters of REG towards β-glucuronidase and the absorption and emission spectrum of REG.



Physical Chemistry

Inverse CeO₂/La₂Sn_1.7Co_0.3O_7-δ Catalyst for Methane Catalytic Combustion^†

LI Lingcong, HU Ruisheng, BAI Yaqin, LI Jingjia, TANG Hailian, WANG Junhu, JI Shengfu

2015, 36(7):  1328-1336.  doi:10.7503/cjcu20150117

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The inverse CeO₂/La₂Sn_1.7Co_0.3O_7-δ catalyst was prepared by sol-gel and impregnation method calcined at 900 ℃ and investigated in the methane catalytic combustion. The catalytic activity evaluated for methane combustion showed that the methane conversion temperature of T₉₀ was 564 ℃, compared with the pure La₂Sn_1.7Co_0.3O_7-δ prepared in the same condition and mechanical mixing of La₂Sn_1.7Co_0.3O_7-δ and CeO₂, T₉₀ decreased by 78 ℃ and 135 ℃, respectively, and the inverse CeO₂/La₂Sn_1.7Co_0.3O_7-δ catalyst not only had the excellent methane combustion activity, but also had the well thermal stability and reusable performance. The excellent performance of the inverse CeO₂/La₂Sn_1.7Co_0.3O_7-δ catalyst was represented by the characterizations of XRD, TEM, AFM, TPR, BET, XPS and Mössbauer spectra. XRD characterization showed that the inverse CeO₂/La₂Sn_1.7Co_0.3O_7-δ catalyst not only had the La₂Sn_1.7Co_0.3O_7-δ structure, but also had the CeO₂ phase, and the CeO₂ had been well disperse on the La₂Sn_1.7Co_0.3O_7-δ composite oxide; TPR indicated that the CeO₂/La₂Sn_1.7Co_0.3O_7-δ had lower reduction temperature compared to La₂Sn_1.7Co_0.3O_7-δ, XPS and Mössbauer spectra indicated that the Sn⁴⁺ is the main valence state in the inverse catalyst, and the lattice oxygen play an important role in catalytic activity; TEM and BET tests showed that the CeO₂/La₂Sn_1.7Co_0.3O_7-δ particles had better dispersed and larger surface area than La₂Sn_1.7Co_0.3O_7-δ. All above explained the reasons of the CeO₂/La₂Sn_1.7Co_0.3O_7-δ catalyst had excellent catalytic activity toward methane combustion.



Investigation on the Factors Affecting Hydrogen Peroxide Concentrations in Natural Biofilm Systems^†

DONG Deming, SUN Jiaqian, ZHAO Tianyu, LI Ming, HUA Xiuyi, LIANG Dapeng, GUO Zhiyong

2015, 36(7):  1337-1343.  doi:10.7503/cjcu20150102

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In this study, hydrogen peroxide(H₂O₂) was selected as a representative of reactive oxygen species(ROS) to investigate the effect of factors, such as light/dark variation, dark pretreatment of biofilms, biofilm quantity, presence of ligands and pH value of the solutions, on H₂O₂ concentrations in natural biofilms-water systems. The results indicated that H₂O₂ concentration increased rapidly under illumination, and the H₂O₂ concentration decreased(to about 2/3) when the systems switched to darkness. Dark pretreatment signi-ficantly reduced both the H₂O₂ concentrations and the increasing rate. The increase and decrease of biofilm quantity led to corresponding change of H₂O₂ concentrations in the systems. The presence of organic ligands reduced the H₂O₂ concentrations(by about 1/2—1/3). H₂O₂ concentrations in neutral and acidic systems(pH=7 and 5) were about 1.5 times as high as that in basic system(pH=9). These factors affected H₂O₂ concentrations in the biofilm systems by affecting three key processes, which were H₂O₂ generation of natural biofilms, H₂O₂ decomposition and H₂O₂ removal by biofilms.



Different Electron-withdrawing Groups in π Spacers Effect on the Performance of Dye-sensitized Solar Cells Based on Triphenylamine-cyanoacrylic Acid Dyes^†

GU Dongmei, ZHANG Jianzhao, ZHANG Ji, LI Haibin, GENG Yun, SU Zhongmin

2015, 36(7):  1344-1350.  doi:10.7503/cjcu20150094

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We performed this work in order to rationalize the negative effect of introducing different electron-withdrawing groups in phenylene-based π-spacers on the performance of dye-sensitized solar cells based on five organic dyes consisting of triphenylamine as donor and cyanoacrylic acid as acceptor. UV-absorption spectrum, the electron injection driving force, the shift of the conduction band energy level and the interaction energy of dye-I₂ and so on, were carried out with density functional theory(DFT) and time-dependent DFT, which are associated with the performance of cell. The results reveal that charge recombination between injected electrons and iodine as well as the electron injection driving force limit the open-circuit photovoltage and the short-circuit current density, respectively, eventually led to the reduce of conversion efficiency. Therefore, in design and development more efficient dyes in future, except for considering the absorption spectrum, the interaction between dyes and I₂ and the electron injection efficiency should be taken into account as the critical factors for the efficiency of dye-sensitized solar cell(DSSC).



Controllable Preparation of Cu₂O Microcrystals and Their Visible-light Photocatalytic Activity Toward Degradation of Methylene Blue^†

LI Feng, WANG Guiyan, ZHANG Yan, LI Hongren

2015, 36(7):  1351-1357.  doi:10.7503/cjcu20150091

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Cuprous oxide microcubes were prepared by solvothermal method in glycol and water medium using copper acetate as copper source, citrate as a shape directing agent. The samples were characterized by X-ray powder diffraction(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS). The results indicate that uniform cubic Cu₂O microcrystals with the size of 0.6—1.5 μm were synthesized at 180 ℃ for 5 h by controlling the molar ratio of sodium citrate to copper acetate. The visible-driven photocatalytic activity of Cu₂O microcrystals toward the degradation of methylene blue(MB) was investigated. The results show that after 100 min visible light irradiation, the degradation rate of methylene blue with initial concentration of 30 mg/L reached 98% by using 0.3 g/L Cu₂O microcrystals in the presence of H₂O₂. The decomposition rate of MB was still above 96% even after 8 recycling uses, thus Cu₂O microcrystals show high catalytic activity and excellent stability. The photocatalytic mechanism was discussed based on the active species during photocatlytic process.



Theoretical Studies on the Phenoxyalkanoic Herbicides Adsorption on Kaolinite Surface^†

WANG Liang, ZHANG Chao, ZHONG Mingjing, QIAN Ping

2015, 36(7):  1358-1366.  doi:10.7503/cjcu20150078

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Octahedral(Al—O) surface model Al₁₃O₄₈H₅₇ and tetrahedral(Si—O) surface model Si₁₃O₃₇H₂₂ were constructed, and the B3LYP/6-31G(d,p) level was used to research the interaction and properties including optimal structures, structural parameters, adsorption energies, natural bond orbit(NBO) charge distributions, between Kaolinite and 2,4-dichlorophenoxyacetic acid(2,4-D), 2,4-dichlorophenoxypropanoic acid(2,4-DP), 2,4-dichlorophenoxybutyric acid(2,4-DB), 2-methyl-4-chlorophenoxyacetic acid(MCPA), 2-methyl-4-chlorophenoxypropanoic acid(MCPP), 2-methyl-4-chlorophenoxybutyric acid(MCPB). Simultaneously, adsorption of MCPP on Kaolinite surface was stronger than that of MCPA. Combined with conclusion of experiment that 2,4-D has higher adsorption than MCPA, we can infer that 2,4-D and MCPA tend to be adsorbed on tetrahedral surface. Therefore, interaction of herbicides on Kaolinite should be taken full account of to ensure the feasibility of leaching in removing herbiside residues in the process of fertilization.



Preparation of Ag₂O/TiO₂ Nanowires Heterojunction and Their Photocatalytic Activity Under Visible-light Irradiation^†

WANG Wei, HE Jiaojie, CUI Fuyi, WANG Ce

2015, 36(7):  1367-1371.  doi:10.7503/cjcu20150051

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In order to improve the activity of TiO₂ based photocatalysts, Ag₂O/TiO₂ nanowire(Ag₂O/TNWs) heterojunctions were prepared via a facile precipitation method. Scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and the decolorization experiment of methyl orange(MO) in aqueous solution were employed to characterize the as-prepared samples. Compared to the particle-structured catalyst of Ag₂O/P25 with the same loading ratio(mass ratio 1∶1), the Ag₂O/TNWs heterojunction exhibited greatly enhanced photocatalytic activities under visible light irradiation, indicating the advantage of the one-dimensional structure of TNWs.



Influence of CuO on Ce-Zr-O₂ Dispersion on Catalytic Properties in CO Oxidation^†

KONG Lingzhi, WANG Qian, XU Li, YAN Yongsheng, LI Huaming, YANG Xiangguang

2015, 36(7):  1372-1377.  doi:10.7503/cjcu20150018

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Ce-Zr-O₂ solid solution was prepared by citric acid method and 10%M/Ce_0.8Zr_0.2O₂ (M=Co, Mn, Cu) and 1%Pt/Ce_0.8Zr_0.2O₂ were prepared by incipient-wetness impregnation method. It was found that Cu was the best active composition in CO oxidation over M/Ce_0.8Zr_0.2O₂, which CO was completely converted into CO₂ at ca. 120 ℃ and was more active than 1%Pt/Ce_0.8Zr_0.2O₂. It was found that the optimum ratio of Ce to Zr was 4, Cu/Ce_0.8Zr_0.2O₂ showed the best activity in CO oxidation. Deposition method(DP), incipient-wetness precipitation method(IW), hydro-thermal method(HT) and citric acid method(CA) were used to prepare 20%Cu/Ce_0.8Zr_0.2O₂ catalysts. Cu/Ce_0.8Zr_0.2O₂ prepared by deposition method showed better activity in CO oxidation, which CO was completely converted into CO₂ at ca. 100 ℃. The data from H₂-TPR showed that the redox of Cu/Ce_0.8Zr_0.2O₂ was not a determining factor to control the CO oxidation. TEM results showed that the CuO was well dispersed on Ce_0.8Zr_0.2O₂. Based on adsorption data of CO and O₂, the high activity of Cu-based catalyst should be ascribed to the week competitive adsorption between CO and O₂ over Cu/Ce_0.8Zr_0.2O₂. The oxygen vacancy on Ce_0.8Zr_0.2O₂ was a crucial factor to affect the CuO dispersion and to reduce the competitive adsorption between CO and O₂.



Effect of IrO₂ Modification of Ti Mesh on Electrochemical Performance of Collector Layer for Solid Polymer Electrolyte Electrolyzer^†

SONG Yukun, LÜ Hong, HAO Chuanpu, MI Cangen

2015, 36(7):  1378-1384.  doi:10.7503/cjcu20150012

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Modified Ti meshes used as anode collector layer of solid polymer electrolyte(SPE) electrolyzer were prepared through Adams fusion method. The Ti mesh modification synchronized with IrO₂ preparation. The physico-chemical properties of the modified Ti meshes and IrO₂ catalyst were studied by scanning electron microscopy(SEM), X-ray diffraction(XRD) and transmission electron microscopy(TEM). An IrO₂ layer was formed onto the Ti mesh’s surface and the size of anode catalyst IrO₂ was in nanoscale. The SPE electrolyzer employing modified Ti mesh showed a higher performance due to the extension of three-phase activity sites from catalyst layer to diffusion layer. 100 mesh Ti mesh showed lower R_ct and better catalyst loadings compared with 50 mesh one, and owned a good durability as well. Ti meshes with different catalyst loadings were tested and the Ti mesh with 1.38%(mass fraction) catalyst loading exhibited the best performance, which yielded a potential of 2.028 V at a current density of 1 A/cm².



Temperature and Morphology Effect on Surface Thermodynamic Functions of Ag₃PO₄ Microcrystals^†

LIU Zuojiao, FAN Gaochao, HE Liangming, DIAO Kaisheng, HUANG Zaiyin, TAN Xuecai

2015, 36(7):  1385-1388.  doi:10.7503/cjcu20150011

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Different morphologies of Ag₃PO₄ microcrystals, such as dodecahedrons, cubes, and tetrapods, were synthesized by ion-exchange method at room temperature. Based on the essential difference between thermodynamic properties of nano and bulk Ag₃PO₄, the equations for acquiring molar surface thermodynamic functions of nano Ag₃PO₄ were derived via combining the basic theory of chemical thermodynamics with thermokinetic principle. According to the derived equations, molar surface thermodynamic properties such as molar surface Gibbs free energy, molar surface enthalpy and molar surface entropy of the prepared Ag₃PO₄ microcrystals were gained by in-situ microcalorimetry. Moreover, the temperature and morphology effect on these obtained surface thermodynamic functions were discussed. The results revealed that the surface thermodynamic functions of tetrapod Ag₃PO₄ were maximum, followed by cube and dodecahedron Ag₃PO₄. Along with the increase of the temperature, molar surface enthalpy and molar surface entropy increased, whereas molar surface Gibbs free energy decreased.



Polydopamine-doxorubicin Colloidal Nanoparticles for Chemo-Photothermal Synergistic Therapy Against Cancer Cell^†

LIU Yuwei, GUO Zhuo

2015, 36(7):  1389-1394.  doi:10.7503/cjcu20141108

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Polydopamine(PDA) nanoparticles were prepared with ethanol and ammonia in water, which performed an excellent light-heat energy conversion ability. An anti-cancer medicine, doxorubicin(Dox), was loaded on the surface of the polydopamine nanoparticles efficiently through π-π stacking and covalent bond, and then the doxorubicin loaded polydopamine(PDA-Dox) nanoparticles were prepared. The drug delivery property of the materials was studied. As a result, the drug release behavior could be controlled by the pH value of the environment, which was improved in acidic condition. When the PDA-Dox nanoparticles were exposed to the laser irradiation, the cancer cell, HeLa, could be killed efficiently by the materials through the chemo-photothermal synergistic therapy. Combined with the laser irradition, the nanomaterial could kill the cancer cell efficiently with the synergistic therapy between the phototherpy and chemotherapy in vitro.



Effect of La(NO₃)₃ and Pr(NO₃)₃ on Kinetic of Dehydroxylation of Kaolinite^†

KUANG Jingzhong, YUAN Weiquan, XU Liyong, LI Lin, HUANG Zhen

2015, 36(7):  1395-1402.  doi:10.7503/cjcu20141004

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The thermal decomposition processes of kaolinite mixed with La(NO₃)₃ and Pr(NO₃)₃ were investigated by thermogravimetric analysis/differential thermal analysis(TG/DTA) simultaneous thermal analysis technique under different heating rates. Thermal analysis data were used for dynamic analysis by the Coats-Redfern integral method and Achar differential method to calculate the kinetic model function, activation energy and pre-exponential factor of dehydroxylation process of kaolinite. The effects of two kinds of rare earth on kinetic parameters of dehydroxylation process of kaolinite were analyzed. The activation energy was validated by Ozawa method. The results show that dehydroxylation of kaolinite and the sample mixed with Pr(NO₃)₃ are controlled by the rate of third-order chemical reaction(F₃), the activation energies are 307.94 and 282.86 kJ/mol, respectively, and the values of pre-exponential factor lnA are 47.8980 and 44.1718, respectively; the kinetic model function of sample mixed with La(NO₃)₃ changes to the second-order chemical reaction(F₂), the activation energy is 196.02 kJ/mol, and the value of pre-exponential factor lnA is 29.5551. Compared with the kaolinite without rare earth, the activation energy and the pre-exponential factor lnA of the sample mixed with Pr(NO₃)₃ have slightly reduced, while those of the sample mixed with La(NO₃)₃ significantly decrease by 36.34% and 38.30%, respectively. The value of the activation energy obtained by Coats-Redfern and Achar method is consistent with the one obtained by Ozawa method.



Polymer Chemistry

Fabrication and Characterization of ZrO₂ Nanofibers with Controllable Crystalline Phase by a Halid-free Approach^†

WU Jie, LU Yanfang, LIU Yang, YU Zheying, XIN Baifu

2015, 36(7):  1403-1408.  doi:10.7503/cjcu20150257

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ZrO₂ nanofibers with controllable crystalline phase were fabricated via a halide-free strategy. Polyvinylpyrrolidone(PVP)/Zr(NO₃)₄ precursor nanofibers were first synthesized using electrospinning method. After sintering such precursor nanofibers at high temperature, the PVP and Zr(NO₃)₄ decomposed and the resulting ZrO₂ nanofibers formed. The crystal structure, morphology and thermal stability were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis. The morphology and crystal structure of ZrO₂ nanomaterials could be tuned by controlling calcination temperature.



Precise Structural Regulation of Poly(L-lactide) Acid Tissue Engineering Scaffolds^†

XUE Li, NIE Taotao, MA Haiyun

2015, 36(7):  1409-1415.  doi:10.7503/cjcu20150231

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A thermal induced phase separation combined sugar template method was used to fabricate the poly(L-lactide) acid(PLLA) scaffolds with a highly controllable inner spatial structure including pore size, inner connectivity and porosity. Scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FTIR) and differential scanning calorimetry(DSC) were used to investigate the spatial structure and property of the PLLA scaffolds. The scaffolds obtained consist of adjustable micro-pores with diameter ranging from 50 μm to 800 μm and inner pore diameter ranging from 10 μm to 200 μm. Different micro- and nano-structures were formed by different solvent systems. The chemical structure of scaffold was little affected by the fabrication method. The crystallinity degree decreased on different levers after phase separation.



Molecular Simulation of Mechanical Property of Poly(phenylenediamine-alt-2,6-diformyl multiphenyl)^†

ZHAO Yao, WU Hongmei, HUANG Huijun, WANG Yuyuan, WANG Meng, DING Yong

2015, 36(7):  1416-1421.  doi:10.7503/cjcu20150201

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Poly(phenylenediamine-alt-2,6-diformyl multiphenyl) was designed. Combination of molecular mechanics(MM) and mechanic properties(MP) modules in Material Studio software were exploited to investigate the mechanical properties of the linear aromatic polyamides. The results show that the linear aromatic polyamides, namely poly(phenylenediamine-alt-2,6-diformyl multiphenyl) can be self assembled as inverted honey-comb like structures. Beyond poly(phenylenediamine-alt-2,6-diformyl biphenyl) and poly(phenylenediamine-alt-2,6-diformyl triphenyl), these linear aromatic polyamides have negative Poisson ratios in xy plane.



Solid-state NMR Study on the Dynamics of Thermo-sensitive Cellulose/Poly(N-isopropylacrylamide) Composite Hydrogel^†

WANG Min, GE Hao, SONG Jianhui, XU Min

2015, 36(7):  1422-1430.  doi:10.7503/cjcu20150174

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The cellulose/poly(N-isopropylacrylamide)(PNIPAM) composite thermo-sensitive hydrogel was prepared by interpenetrating polymer network(IPN) approach. Various solid-state nuclear magnetic resonance(NMR) methods including ¹³C cross polarization/magic angle spinning nuclear magnetic resonance(CP/MAS NMR), ¹³C quantitative cross polarization(QCP) NMR, static ¹H NMR and ¹H filtering-spin diffusion NMR experiments were performed to analyze the structure, content, property and dynamics of the composite thermo-sensitive hydrogel. The results show that the cellulose/PNIPAM composite hydrogels have obvious temperature sensitivity. Cellulose molecules are relatively rigid while PNIPAM molecules are flexible. The space between cellulose and PNIPAM chains are very close.



Synthesis and Morphology Control of Janus Nanomaterials^†

ZHOU Peng, LIU Bao, LIANG Fuxin, WANG Qian, QU Xiaozhong, YANG Zhenzhong

2015, 36(7):  1431-1436.  doi:10.7503/cjcu20150152

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We propose a facile method to synthesize Janus nanomaterials by seed interfacial sol-gel process against a polystyrene(PS) hollow sphere using three precursor silanes, (3-aminopropyl) triethoxysilane(APTES), methacryloxy propyl trimethoxyl silane(MPS) and tetraethyl orthosilicate(TEOS). The sol-gel process starts from the exterior surface of the seed sphere. Janus nanomaterials were formed in situ onto the seed sphere surface after a self-organized sol-gel process, which possess 3-methacryloxypropyl- and amine- groups terminated at both sides of the shell. Morphology of the Janus nanomaterials could be tunable from intact shell, nanosheet, porous nanosheet and individual nanoparticles by controlling pH, precursor amount and the fraction of binary emulsifier system. After the removal of PS by dissolution under ultrasonication, Janus nanoparticles were eventually achieved. This method is attractive owing to the easiness to continuously adjust morphology of the Janus nanomaterials. On the other hand, composition of the nanomaterials is also flexibly tunable by using different precursors. What’s more, the Janus nanomaterials can derive other Janus ones after selective modification and favorable growth of desired materials onto the corresponding side.



Influence of Triethylenetetraamine on Properties of Sulfonated Polyacrylamide^†

CAO Xulong, HU Yue, SONG Xinwang, ZHU Yangwen, HAN Yugui, WANG Kunpeng, CHEN Yong, LIU Yu

2015, 36(7):  1437-1440.  doi:10.7503/cjcu20150043

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The water-soluble negatively charged polyacrylamide was prepared by free radical copolymerization method. The interaction between negatively charged sulfonated polyacrylamide and triethylenetetraamine was investigated in aqueous solution and mineralized water. The results indicated that the addition of triethylene-tetraamine can efficiently influence the viscosity and rheological properties of sulfonated polyacrylamide, which provides the theoretical basis for the further application in oil displacement.



Evaporation of Sessile Droplet on Grooved PDMS Substrate and Resultant Cassie-Wenzel Transition^†

ZENG Mengmeng, ZHU Yu, YOU Jichun, LI Yongjin

2015, 36(7):  1441-1446.  doi:10.7503/cjcu20141035

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The evaporation of sessile droplets(water) on grooved polydimethylsiloxane(PDMS) substrate was investigated in detail. The contact angles and diameters of the droplet show clear difference between vertical (V) and parallel (P) directions, indicating the anisotropy of the droplet. Upon evaporation, three stages including constant diameter mode(CDM), constant contact-angle mode(CCM) and combination mode of them have been tracked as well as the results on the flat PDMS. The transition from Cassie to Wenzel state, leading to the simultaneous quick increase of the contact diameter and the sudden decrease of the height and contact angle, was observed in the first stage(CDM). The transition time depends crucially on the area fraction of the protrusion. Furthermore, the anisotropy of the droplet disappears, resulting in the equal diameters in P and V directions in the second stage ( CCM). The results are significant for the control of superhydrophobicity surface.



Structures and Properties of in situ Polymethacrylates/Low-temperature Hydrogenated Butadiene-acrylonitrile Rubber^†

ZHANG Jihua, FENG Huadong, ZAO Weitao, LING Mingbo, LIU Xiaoyan, ZHAO Yunfeng

2015, 36(7):  1447-1454.  doi:10.7503/cjcu20140788

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Salts of poly(methacrylic acid)(SPMAA) modified low-temperature hydrogenated butadiene-acrylonitrile rubber(HNBR) composites were prepared by in situ polymerization of alkali and methacrylic acid(MAA). The effects of SPMAA cations(Na⁺, Mg²⁺ and Al³⁺) on the properties of rubber composites were carefully analyzed by scanning electron microscope, transmission electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry and oil-swelling experiments. With the increase of cation’s charge numbers, ion clusters were developed in the rubber bulk which leads to the weak compatibility between SPMAA and rubber, even big aggregations generated. Various properties of aluminum polymethacrylate(AlSPMAA) modified rubber composites, including the tensile strength and oil-swelling resistance, were far less than those of sodium and magnesium polymethacrylates(NaSPMAA and MgSPMAA) due to these structures of phase separation. Importantly, the glassy temperatures of all rubber composites barely changed neglect of the SPMAA’s species, maintaining the elasticity at the temperature of -30 ℃. Therefore, we believe that the properties of low-temperature HNBR composites can be well tuned by varying the cations of in situ polymethacrylates.