APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Xiao Shang,Kai-Li Yan,Zi-Zhang Liu,Shan-Shan Lu,Bin Dong,Jing-Qi Chi,Xiao Li,Yan-Ru Liu,Yong-Ming Chai,Chen-Guang Liu
Oxidized carbon fiber (oCF) as support successfully realizes the vertical growth of uniform WS 2 nanosheets arrays for efficient hydrogen evolution reaction (HER) via a facile hydrothermal process. Thanks to oxygen functional groups on oCF, vertical WS 2 nanosheets structures have grown more easily on oCF, which can provide better dispersion, short charge transfer distance and more exposed active sites for HER in comparison with bulk WS 2 and WS 2 nanosheets on bare carbon fiber (CF) fabricated at the same condition. The electrochemical measurements confirmed that WS 2 /oCF possesses better HER activity than bulk WS 2 and WS 2 /CF. Especially, the 10-h stability with unchanged vertical WS 2 nanosheets morphology further demonstrate the positive effect of oxygen functional groups on the enhanced vertical structure and close combination between WS 2 and oCF. It may offer a facile way to realize more exposed active sites from stable electrocatalyst hybrids of transition metal sulfides by surface oxidization of carbon supports.
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JOURNAL OF CHEMICAL THERMODYNAMICS
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2016
·
IF 2.196
Yaran Yin,Chunying Zhu,Youguang Ma
Densities and viscosities of binary {[Bmim][BF 4 ] + H 2 O}, {[Bmim][BF 4 ] + MEA}, (MEA + H 2 O) and ternary mixtures {[Bmim][BF 4 ] + MEA + H 2 O} were measured at T = (293.15–333.15) K. The volumetric and viscometric properties, such as excess molar volume V E , viscosity deviation Δ η , and excess Gibbs energy of activation of viscous flow Δ G ∗E for all mixtures, and apparent molar volume, excess partial molar volume and Grunberg-Nissan interaction parameter G 12 for binary mixtures, were deduced from experimental results, and the intermolecular interactions in solutions were also analysed. The excess molar volumes were correlated using the Redlich-Kister polynomial equation for binary mixtures, and Singh et al. equation for the ternary mixture with corresponding binary parameters. The viscosities of binary and ternary solutions were respectively fitted by Jouyban-Acree equation and its extended equation at each measurement temperature, the correlated values are in good agreement with the corresponding experimental data.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2016
·
IF 2.567
Shuai Zhou,Xiang Zhou,Wei Jiang,Tianhe Wang,Ning Zhang,Yue Lu,Liuhua Yu,Zuozhu Yin
Robust superhydrophobic and exceptionally thermostable graphene aerogels exhibiting a three-dimensional macro- and mesoporous structure have been synthesized through a (3-mercaptopropyl)trimethoxysilane-assisted two-step route with natural drying. The facile synthetic process not only guarantees their excellent performance but also greatly improves their practical production rate. The prepared graphene aerogels hold excellent superhydrophobicity, for which water contact angle exceeded 160 degrees, even after 20 ethanol washing–drying cycles. Furthermore, the self-assembly functionalized-graphene sheets enhance the thermal stability of the nanocomposites, due to the good dispersion of functionalized-graphene sheets and the strong bonding between graphene sheets and polymer chains within the aerogels. The study implies a novel and practical methodology to efficiently fabricate three-dimensional composite materials with enhanced performances.
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ChemCatChem
·
2016
·Vol. 9
·期 3
·458-464
·
IF 4.724
Ting Yang,Lan-Lan Lou,Wenjun Yu,Yajun Feng,Hao Li,Kai Yu,Shuangxi Liu
Graphical Porous but extraordinarily durable : 3 D ordered macroporous alumina–carbon composite supported Pt nanocatalysts are applied in the asymmetric hydrogenation of ethyl pyruvate. They exhibit high catalytic activity and extraordinary durability. The three-dimensionally ordered macroporous alumina-carbon composite materials were firstly prepared through a surfactant-assisted colloidal crystal template method and applied to support Pt nanoparticles. The results of SEM, XRD, TEM, and N 2 sorption analyses revealed that these composite materials possessed highly ordered macroporous structures with meso- and micropores within the skeletons of macropores and that the Pt nanoparticles were well dispersed on these materials with a very narrow size distribution. These prepared Pt nanocatalysts were evaluated in the asymmetric hydrogenation of ethyl pyruvate after chiral modification with cinchonidine. Excellent catalytic activity and enantioselectivity were achieved. More importantly, these catalysts exhibited extraordinary stability and reusability during the reaction and could be reused at least 26 times without significant loss in catalytic activity and enantioselectivity.
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RSC Advances
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2016
·Vol. 6
·期 107
·105723-105728
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IF 3.289
Cheng Chen,Yan Li,Lijian Liu
Oligomers as fluorescent macromolecules are of significant importance and are fairly attractive for high quantum yield two-way conversion luminescence. We report a high conversion rate (ΦF = 0.5184) for a fluorescent oligomer, 1,4-butanediol-bis(5-carbonyl-3-carbethoxy-2-pyrazoline). It was prepared by the novel cyclopolycondensation of 1,4-butanediol-bis(5-carbonyl-3-carbethoxy-2-pyrazoline), a chromophore with good fluorescence (ΦF = 0.0573). After polymerization, a green fluorescent protein (GFP)-mimetic structure was formed, in which a methylene chain (–CH2–CH2–CH2–CH2–) as a flexible group is beneficial due to its folding, and an azo group sits in the rigid pyrazoline ring because of a resonance effect. These factors collectively contribute to the excellent efficiency of the fluorescence performance of the oligomer. Additionally, the oligomer exhibited a weak red shift and a significant fluorescence enhancement compared with the monomer, and we achieved good quality live-cell imaging. The oligomer also allowed for the enhancement of fluorescence intensity through the two-wavelength excitation of a cell rather than increasing the dosage of the dye or the power of the laser.
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INORGANIC CHEMISTRY
·
2017
·
IF 4.857
Yi-Gang Chen,Nan Yang,Xing-Xing Jiang,Yao Guo,Xian-Ming Zhang
The first lead tellurate–nitrate nonlinear-optical (NLO) crystal, Pb9Te2O13(OH)(NO3)3, featuring a 3D anionic diamondlike toplogical structural motif formulated as [Pb9O13]8– constructed by unique nonanuclear basket-shaped Pb@Pb8O14 clusters has been hydrothermally achieved, in which the Pb@Pb8O14 cluster shows a core–shell structure with one PbO10 polyhedron enclosed by eight PbOx (x = 3 and 4) polyhedera via edge and face sharing. The hexavalent Te in TeO5(OH) octahedra is linked to a [Pb9O13]8– cluster to form a rare [Pb9Te2O13(OH)]3+ cationic framework. The compound demonstrates a powder second-harmonic-generation (SHG) response of about 1.2 times that of KH2PO4 (KDP) as well as a wide transparency range. Calculations on the local dipole moment and SHG coefficient reveal that the net polarization is zero because of a Kleinman-forbidden point group. Further analysis shows that the SHG response results from structure-induced variations by thermal vibrations of the lattice rather than the intrinsic dipole moment, which offers another insight on the design of new NLO materials.
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FOOD CHEMISTRY
·
2016
·
IF 4.052
Xiumei Wang,Daoming Li,Man Qu,Rabia Durrani,Bo Yang,Yonghua Wang
Immobilization of lipase MAS1 from marine Streptomyces sp. strain W007 and its application in catalyzing esterification of n-3 polyunsaturated fatty acids (PUFA) with glycerol were investigated. The resin XAD1180 was selected as a suitable support for the immobilization of lipase MAS1, and its absorption ability was 75 mg/g (lipase/resin ratio) with initial buffer pH value of 8.0. The thermal stability of immobilized MAS1 was improved significantly compared with that of the free lipase. Immobilized MAS1 had no regiospecificity in the hydrolysis of triolein. The highest esterification degree (99.31%) and TAG content (92.26%) by immobilized MAS1-catalyzed esterification were achieved under the optimized conditions, which were significantly better than those (82.16% and 47.26%, respectively) by Novozym 435. More than 92% n-3 PUFA was incorporated into TAG that had similar fatty acids composition to the substrate (n-3 PUFA). The immobilized MAS1 exhibited 50% of its initial activity after being used for five cycles.
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ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Jingjing Lin,Xiaoming Yan,Gaohong He,Wanting Chen,Dongxing Zhen,Tiantian Li,Lin Ma,Xuemei Wu
A new series of thermoplastic interpenetrating polymer network (TIPN) anion exchange membranes (AEMs) based on poly [2,2′- (p-oxydiphenylene) −5, 5′-bibenzimidazole] (OPBI) and poly(1, 2-dimethy-3-allylimidazolium) (PDAIm) (PBI/DAIm TIPN) has been developed. With 1, 2-dimethy-3-allylimidazolium (DAIm) polymerization in presence of OPBI polymer chains, two kinds of uncrosslinked polymer chains, i.e. PDAIm and OPBI interpenetrate with each other to form a physically crosslinking network. Small steric hindrance effect of the DAIm monomer and non-covalent crosslinking interpenetrating polymer chains contribute to better compatibility and chains flexibility in the TIPN compared with the blend and semi-interpenetrating networks, which are evidenced by SEM and SAXS, promote the aggregation of hydrophilic groups and induce connective ionic conductive channels. PBI/DAIm TIPN membranes achieve well-balanced performance between high hydroxide conductivity and dimensional stability because of the dynamically forced compatibility feature of TIPN. Especially, the PBI/DAIm TIPN-65/0.5 membrane exhibits high hydroxide conductivity (96.7 mS cm −1 ) and low swelling ratio (4.4%) at 80 °C. With low overall alkali uptake (2.89%) and IEC (0.63 mmol g −1 ) of functional groups, it exhibits excellent chemical stability in 1 M KOH at 60 °C for 96 h (94.0% retention) and high tensile strength (48.2 MPa) in hydrated state. These observations suggest TIPN structure provides a promising solution to the electrochemical-mechanical balance of AEMs.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2015
·Vol. 53
·期 21
·2469-2480
·
IF 3.113
Yong Deng,Xi Wang,Qiulin Yuan,Mengxiang Zhu,Ying Ling,Haoyu Tang
A series of side-chain-functionalized α-helical polypeptides, i.e., poly(γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamate) (6) have been prepared from n-butylamine initiated ring-opening polymerization (ROP) of γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamic acid-based N -carboxyanhydride. Polypeptides bearing oligo-ethylene-glycol (OEG) groups or 1-butylimidazolium salts were prepared from 6 via copper-mediated [2+3] alkyne-azide 1,3-dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α-helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side-chains showed reversible LCST-type phase transition behaviors in water while polymers bearing 1-butylimidazolium and I − counter-anions exhibited reversible UCST-type transitions in water. Variable-temperature UV-vis analysis revealed that the phase transition temperatures ( T pt s) were dependent on the main-chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53 , 2469–2480
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ANALYST
·
2015
·Vol. 140
·期 17
·6047-6053
·
IF 4.107
Min Zhong,Yunlong Dai,Limei Fan,Xiaojing Lu,Xianwen Kan
A facile electrochemical sensor for hydroquinone (HQ) and catechol (CC) determination was successfully fabricated by the modification of poly(3-aminophenylboronic acid) (pAPBA) film and multi-walled carbon nanotubes (MWCNTs) on a glassy carbon electrode (pAPBA/MWCNTs/GCE). The prepared sensor was characterized by scanning electron microscope and electrochemical impedance spectroscopy. Under optimal conditions, differential pulse voltammetry was employed to quantify individual HQ and CC within the concentration range of 5.0 × 10−7–4.0 × 10−5 mol L−1 and 7.0 × 10−6–1.0 × 10−4 mol L−1, respectively. Based on the covalent binding between the boronic acid groups of pAPBA film and the cis-diol-containing molecule, a novel substitution-sensing strategy was proposed for the highly sensitive determination of CC. With the addition of CC into HQ solution, covalent interaction between CC and APBA occurred and the HQ was displaced by CC, resulting in a decrease of HQ oxidation peak current and the increase of the CC oxidation peak current. The summation of both current changes (Δ|IHQ| + Δ|ICC|) were combined for CC sensitive detection in a concentration range of 4.0 × 10−8–1.7 × 10−5 mol L−1 with a limit of detection of 4.3 × 10−9 mol L−1. The sensor was successfully applied to the determination of CC in spiked water samples.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2015
·
IF 4.097
Jianmei Wang,Huihui Zhu,Yuanhong Xu,Wenrong Yang,Ao Liu,Fukai Shan,Mengmei Cao,Jingquan Liu
Herein, a uniform three-dimensional (3-D) graphene nanodots-encaged porous gold electrode was prepared via ion beam sputtering deposition (IBSD) and mild corrosion chemistry for efficient enzyme electrode fabrication. Enzymes, like glucose oxidase and catalase , were modified with pyrene functionalities and then loaded into the graphene nanodots encaged porous gold electrode via non-covalent π–π stacking interaction between pyrene and graphene. The fabricated enzyme electrodes showed profound reusability and repeatability, high sensitivity, inherent selectivity and enhanced detection range. As for glucose analysis a broad linear range from 0.05 to 100 mM was obtained and the linear range for hydrogen peroxide was 0.005 to 4 mM. Detection limits of 30 μM for glucose and 1 μM for hydrogen peroxide were achieved ( S / N = 3), respectively. These electrodes can be applied to analyze the clinical samples with reliable results. The formation mechanism and 3-D structure of the porous electrode were investigated using high resolution transmission electron microscope (HRTEM), atomic force microscopy (AFM), scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS). Most importantly, various other ideal biosensors can be fabricated using the same porous electrode and the same enzyme modification methodology.
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FLUID PHASE EQUILIBRIA
·
2015
·
IF 2.2
Hao Wu,Jing Zhu,Yiwei Wang,Chengwei Chang,Junsu Jin
To understand the phase behavior of 3-hydroxybenzaldehyde (3-HBA) and the solubility effect of 3-HBA and 4-hydroxybenzaldehyde (4-HBA) on each other in supercritical carbon dioxide (SCCO 2 ), the equilibrium solubility of 3-HBA and its mixture with 4-HBA, was measured in SCCO 2 binary system (comprising of a solute and SCCO 2 ) and ternary system (comprising of two solutes and SCCO 2 ) at temperature and pressure given in range of 308–328 K and 11.0–21.0 MPa respectively. Comparing the solubility of 3-HBA and 4-HBA between in the binary system and ternary system, it was found that the equilibrium solubility of both 3-HBA and 4-HBA was enhanced in the ternary system due to the molecular interaction. The experimental data were correlated by Chrastil, Mendez-Santiago and Teja (M-S-T), Sovova, their modified models, and Zhu et al. model. Also a new model was deduced and established based on the Chemistry Association Theory and was verified by 636 groups of solubility data. The correlated results indicated that the new model obtained a less deviation than other models, including the modified Chrastil model, the modified M-S-T model, the modified Sovova model, and Zhu et al. model, all of which have same adjustable parameters.
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