SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Ying Wang,Zhenting Zhao,Yongjiao Sun,Pengwei Li,Jianlong Ji,Yong Chen,Wendong Zhang,Jie Hu
Pristine tin dioxide (SnO 2 ) and Au-loaded SnO 2 composite nanoparticles were synthesized by a simple hydrothermal method. The phase structure, composition, and morphology of synthesized Au-loaded SnO 2 composite nanoparticles were comprehensively investigated. Furthermore, the gas sensing performance of the as-prepared pristine and Au-loaded SnO 2 gas sensors toward low concentration of hydrogen (H 2 ) were systematically evaluated. The results indicated that compared to the pristine SnO 2 gas sensor, the Au-loaded SnO 2 composite nanoparticles could not only significantly improve the gas sensing response, but also decrease the optimum working temperature. Moreover, the experimental results showed that the 4.0 at.% Au-loaded SnO 2 gas sensor exhibited the highest response (25) to 100 ppm H 2 at 250 °C, which was about five times higher than that of the pristine one. In addition, it also provided a rapid response/recovery time (1 s/3 s) and a low detection limit (1 ppb). Therefore, Au-loaded SnO 2 composite nanoparticles are more suited for hydrogen detection compared to pristine SnO 2 gas sensor.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2016
·Vol. 28
·期 1
·958-962
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IF 1.798
Wang Han,Li Haiying,Li Shouchun,Liu Li,Wang Lianyuan,Guo Xuexin
Biomorphic In 2 O 3 –ZnO hollow microtubules were synthesized by using cotton as template and followed by calcination. This environmental-friendly method using biomaterials as templates can be used to synthesize metal oxide semiconductor materials with specific morphologies. The structural and microscopy characterization were carried out with X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. The SEM images display the porous structure of the as-obtained hollow microtubules, which is beneficial to increase gas sensing properties of materials. Gas sensors based on In 2 O 3 -doped ZnO hollow microtubules were investigated and the test results demonstrate the excellent acetone sensing properties of such porous materials. The response of In 2 O 3 –ZnO hollow microtubule sensors to 100 ppm acetone at the optimum temperature of 300 °C is 62.5, meanwhile the response and recovery times are 3 and 7 s, respectively. Moreover, even at 0.1 ppm of acetone detectable response can be observed, and the value is 2.82. At the same time the sensors have selectivity to acetone.
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Journal of Materials Chemistry A
·
2016
·Vol. 4
·期 39
·15072-15080
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IF 8.262
Yuwan Yang,Bien Tan,Colin D. Wood
The preparation of soluble microporous polymers for large-scale gas storage and separation with low cost, scalability and synthetic diversification is extremely challenging. Here, we report the synthesis of solution-processable hypercrosslinked polymers (SHCPs) by folding polystyrene molecules at high dilution. A low cost knitting method is employed and by slowly adding an external crosslinker, intramolecular cross-links were introduced. Despite being highly cross-linked, the resulting hypercrosslinked polymers dissolve in a range of organic solvents to form thermodynamically stable homogenous liquids. By increasing the concentration of polystyrene and the amount of crosslinker, the BET surface area of SHCPs increased with the largest surface area of 724 m2 g−1. Moreover, they also show comparable gas uptake properties reaching 8.11 wt% CO2 adsorption (1.13 bar and 273 K), 1.01 wt% H2 adsorption (1.13 bar and 77 K), and 0.14 wt% CH4 adsorption (1.13 bar and 273 K). The reaction offers a route to new classes of solution-processable microporous polymers as promising materials for gas storage and separation.
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ANALYTICAL LETTERS
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2014
·
IF 1.019
Na Wang,Jing Liu,Ling He,Tie Zhou,Bo Rong,Liang Wang,Xiang Zhao
An effective method for characterizing Chinese lacquer as binding medium in historical artwork has been developed by on-line methylation pyrolysis-gas chromatography–mass spectrometry (pyrolysis GC–MS). The characteristic pyrolytic components of Chinese lacquer were identified in artificially aged pure and pigmented lacquer. Methylation of urushiol (mainly composed of catechol derivatives) was performed by adding tetramethyl ammonium hydroxide to convert phenolic hydroxyl groups into methylated derivatives to improve the resolution of catechol derivatives and urushiol monomers. The mechanism of formation of small molecular components was proposed, and the influence of different mineral pigments (azurite, malachite, ochre, and cinnabar) on the determination of characteristic components was discussed. Aliphatic hydrocarbon components, benzene derivatives, catechol derivatives, and urushiol monomers were proposed as characteristic pyrolytic components. In addition to 3-pentadecene-catechol, 3-pentadecane-catechol, and 3-heptadecene-catechol, 3-pentadecene-phenol was also identified as an urushiol monomer in Chinese lacquer. Four pigments slightly reduced the detection of aliphatic hydrocarbon components, but were unconspicuous for the detection of benzene derivatives. Azurite, malachite, and cinnabar decreased the measurement of urushiol monomers, but ochre significantly increased their relative abundance. The established on-line methylation pyrolysis GC–MS procedure and summarized data were successfully applied to the identification of samples collected from Terra-Cotta Warriors and Horses of Qin Dynasty (221–207 BC), Han Yang Mausoleum of Han Dynasty (206 BC–24 AD), and Dazu Grotto of Tang Dynasty (618–907 AD).
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2015
·
IF 2.729
Jinkai Hao,Shuchun Yu,Yongyi Jiang,Xiaojin Li,Zhigang Shao,Baolian Yi
In this paper, antimony doped tin oxide (ATO) was firstly used as a conductive material in the microporous layer (MPL). ATO had higher electrochemical stability than XC-72 carbon powder. With the same thickness of MPL, the electrochemical corrosion behavior of gas diffusion layers (GDLs) prepared with ATO and XC-72 carbon powder in the simulated PEMFC operation environment were examined and the results showed that the GDL prepared with ATO had higher durability after oxidation for 55 h. Besides, the fuel cell performance with the GDLs prepared with ATO and XC-72 carbon powder as the cathode GDLs were evaluated and a very small difference between those two cells was observed at low current densities, which demonstrated that GDL prepared with ATO had wide application prospects.
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Analytical Methods
·
2015
·Vol. 7
·期 7
·3229-3237
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IF 1.821
Xueyan Zhang,Hongyun Ji,Xudong Zhang,Zhen Wang,Dan Xiao
Graphene Quantum Dots (GQDs) have potential to be an excellent stationary phase because of their high surface area, adsorption affinities and rich functional groups. The rich functional groups of GQDs can form hydrogen bonding and π–π electrostatic stacking interactions with volatile aromatic compounds or unsaturated organic compounds. Herein, GQDs were explored as the stationary phase for gas chromatographic capillary column separation of alkanes and aromatic isomers with 3-aminopropyldiethoxymethyl silane (3-AMDS) as the coupling reagent. GQD coated capillary columns exhibit high separation efficiency for ethylbenzene, styrene, xylene, propylbenzene, alkanes, and dichlorobenzene isomers at low temperature. The elution sequence of the analytes follows an increasing order of their boiling points, even for p-dichlorobenzene and m-dichlorobenzene, which have close boiling points (p-dichlorobenzene, 173.4 °C, m-dichlorobenzene, 173 °C). The separation behavior of the column for different organic substances is related to van der Waals forces or π–π interactions between the test analytes and GQDs. Compared with the commercial HP-5 and HP-innowax capillary columns, GQD coated columns allowed fast and efficient separation of the analytes at low temperature without temperature-programming. The relative standard deviations (RSD) of five replicate separations for the test analytes on the GQD coated capillary column were 0.1–1.6%, 0.7–4.0%, 0.8–8.5%, and 1.2–2.2% for retention time, peak area, peak height, and half peak width, respectively.
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JOURNAL OF MEMBRANE SCIENCE
·
2014
·
IF 4.908
Hong Wu,Xueqin Li,Yifan Li,Shaofei Wang,Ruili Guo,Zhongyi Jiang,Chan Wu,Qingping Xin,Xia Lu
Facilitated transport mixed matrix membranes (FT-MMMs) were fabricated by incorporating polyethylenimine functionalized ordered mesoporous silica (PEI-MCM-41) into poly(ether-block-amide) (Pebax ® MH 1657). The polyethylenimine both in the pore channels and on the surface of MCM-41 rendered abundant amine carriers to facilitate the transport of CO 2 through reversible reaction and simultaneously improved the filler–polymer interface compatibility. The membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile test, dynamic mechanical analysis (DMA), and X-ray diffraction (XRD). The results indicated that incorporation of PEI-MCM-41 generated stronger interfacial interactions and resulted in higher polymer chain rigidification at the filler–polymer interface compared with unmodified MCM-41. The as-prepared FT-MMMs showed increased gas permeability and selectivity, and the highest ideal selectivities for CO 2 /CH 4 and CO 2 /N 2 were 41 and 102 (at a CO 2 permeability of 1521 Barrer), respectively. Compared to the membranes doped with pristine MCM-41, the permeability, the ideal CO 2 /CH 4 selectivity and the ideal CO 2 /N 2 selectivity of the PEI-MCM-41-doped membranes were increased by 102.3%, 115.8% and 96.1%, respectively, at 20 wt% filler loading and surpassed the 2008 Robeson upper bound line.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2013
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IF 2.39
Haiyan Song,Heng Yang,Xicheng Ma
Three porous ZnO nanostructures were synthesized by annealing their basic zinc carbonate (BZC) precursors, which were prepared via a simple hydrothermal process using urea solution with different zinc salts (zinc acetate, zinc chloride or zinc sulfate) under the same conditions. The influences of different anonic species (CH 3 COO − , Cl − and SO 4 2 - ) on the morphologies, structures and gas sensing performances of the obtained porous ZnO nanostructures have been reported. The products were characterized by XRD, TG-DSC, FTIR, SEM, TEM and BET. All the BZC precursors are the mixture of Zn 5 (CO 3 ) 2 (OH) 6 and Zn 4 CO 3 (OH) 6 ·H 2 O. After annealing, porous ZnO nanostructures obtained from zinc sulfate show the largest specific surface areas. SAED patterns of the same size selected area (500 nm in diameter) show that the porous ZnO nanostructures obtained from zinc sulfate and zinc chloride often display polycrystalline nature, while those obtained from zinc acetate often display single or quasi-single crystalline nature. The gas sensing performances of these three porous ZnO nanostructure samples toward some typical volatile organic compounds (including acetone, 2-chlorophenol and formaldehyde, etc.) were investigated comprehensively. The porous ZnO nanostructure obtained from zinc sulfate shows the most superior gas-sensing properties, followed in turn by the ZnO samples obtained from zinc chloride and zinc acetate. The results are tentatively attributed to the different total specific surface area, crystalline nature and accumulated morphologies of the porous ZnO samples.
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RSC Advances
·
2014
·Vol. 4
·期 104
·60253-60259
·
IF 3.708
Jianjiang He,Chunge Niu,Chao Yang,Jide Wang,Xintai Su
Reduced graphene oxide (rGO)–zinc oxide (ZnO) composites were synthesized by a two-step hydrolysis–calcination method, using GO and Zn(Ac)2 as precursors. The structure and morphology of the as-prepared samples were characterized by thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and field emission scanning electron microscopy. It was shown that the well-dispersed ZnO nanoparticles (NPs) were deposited on rGO homogeneously. So far as ZnO NPs with different diameters were synthesized in the varied samples, the ZnO NPs with an average diameter of around 10 nm which were obtained at the heating temperature of 300 °C for 4 h exhibited higher photocatalytic activity than the others. A relatively low amount of rGO–ZnO composites (5 mg) demonstrated enhanced photocatalytic activity to decompose methyl orange (MO, 40 mg L−1) and methylene blue (MB, 10 mg L−1) under low-power ultraviolet light. Furthermore, rGO–ZnO composites exhibited high sensitivity, and a response can be achieved at 50.09 to 1000 ppm acetone. In addition, the ultraviolet light-induced photocatalytic mechanism as well as gas sensing mechanism was also discussed. Both rGO and crystallinity played important roles in improving photocatalytic activity and gas sensing properties.
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WATER RESEARCH
·
2015
·
IF 5.528
Tiecheng Wang,Guangzhou Qu,Jingyu Ren,Qiuhe Yan,Qiuhong Sun,Dongli Liang,Shibin Hu
Degradation of humic acid (HA), a predominant type of natural organic matter in ground water and surface waters, was conducted using a gas phase surface discharge plasma system. HA standard and two surface waters (Wetland, and Weihe River) were selected as the targets. The experimental results showed that about 90.9% of standard HA was smoothly removed within 40 min's discharge plasma treatment at discharge voltage 23.0 kV, and the removal process fitted the first-order kinetic model. Roles of some active species in HA removal were studied by evaluating the effects of solution pH and OH radical scavenger; and the results presented that O 3 and OH radical played significant roles in HA removal. Scanning electron microscope (SEM) and FTIR analysis showed that HA surface topography and molecular structure were changed during discharge plasma process . The mineralization of HA was analyzed by UV–Vis spectrum, dissolved organic carbon (DOC), specific UV absorbance (SUVA), UV absorption ratios, and excitation-emission matrix (EEM) fluorescence. The formation of disinfection by-products during HA sample chlorination was also identified, and CHCl 3 was detected as the main disinfection by-product, but discharge plasma treatment could suppress its formation to a certain extent. In addition, approximately 82.3% and 67.9% of UV 254 were removed for the Weihe River water and the Wetland water after 40 min of discharge plasma treatment.
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PubMed
高影响因子
CATALYSIS COMMUNICATIONS
·
2015
·
IF 3.699
Kun Liu,Zhaoxiang Chen,Peipei Zou,Yuanyuan Wang,Liyi Dai
The oxidation of alcohols to carbonyl compounds in gas-phase is of great importance in organic chemistry and industrial process. Herein, the catalyst CuPd–Cu 2 O/Ti-powder is prepared by depositing Cu(NO 3 ) 2 and Pd(NO 3 ) 2 on Ti powder support followed by in-situ activation in reaction stream, which delivers high-performance for the gas-phase oxidation of alcohols. Compared with Cu/Ti-powder and Pd/Ti-powder, CuPd–Cu 2 O/Ti-powder exhibits higher stability and activity in alcohol oxidation reaction. The catalyst is characterized by XRD, XPS, TEM and ICP. The results indicate that CuPd(alloy)–Cu 2 O formed during the reaction contributes to the high activity and stability.
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JOURNAL OF SEPARATION SCIENCE
·
2017
·Vol. 40
·期 13
·2769-2778
·
IF 2.557
Jia-Ling Dai,Li-Hua Zhao,Jie-Hua Shi
1-Butyl-3-[(3-trimethoxysilyl)propyl]imidazolium chloride ionic liquid was synthesized and chemically modified onto the inner wall of a fused capillary column as a stationary phase for gas chromatography. The 1-butyl-3-[(3-trimethoxysilyl)propyl]imidazolium chloride ionic liquid bonded capillary column was evaluated in detail. The results revealed that the ionic liquid bonded capillary column exhibited high column efficiency of 1.08 × 10 4 plates/m, and good chromatographic separation selectivity ( α ) for polar and non-polar substances, and a good thermal stability between room temperature and 400°C. Moreover, the determination of thermodynamic parameters and the linear solvation energy relationship were further carried out. The results indicated that the chromatographic retention of each probe molecule on the ionic liquid bonded stationary phase was an enthalpy-driven process, and the system constants of the linear solvation energy relationship signified that the dispersion interaction, the hydrogen bonding acidity and hydrogen bonding basicity were dominant interactions between probes and stationary phase among five interactions during the chromatographic separation. However, the contribution of each specific interaction for the stationary phase is ranked as the dispersion interaction > the hydrogen bonding basicity > the hydrogen bonding acidity.
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