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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高影响因子
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
Analytical Methods
·
2015
·Vol. 7
·期 7
·3229-3237
·
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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高影响因子
ANALYTICAL LETTERS
·
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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高影响因子
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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高影响因子
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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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2013
·
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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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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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Xiao Wang,Shouwei Zhang,Minghui Shao,Jinzhao Huang,Xiaolong Deng,Peiyu Hou,Xijin Xu
ZnO/ZnFe 2 O 4 hollow nanocages have been designed and synthesized through a metal organic frameworks route, which involves two steps including the synthesis of Fe(III)MOF-5 nanostructured cages precursors and the subsequent transformation to ZnO/ZnFe 2 O 4 hollow nanocages by thermal annealing in air. The ZnO/ZnFe 2 O 4 architecture is constructed by hollow nanocages with the scale around 100 nm. To demonstrate its functional properties, the as-prepared products are utilized as sensing material for gas sensor. Significantly, the ZnO/ZnFe 2 O 4 hollow nanocages exhibit enhanced response to acetone (25.8) with the detection limit of 1 ppm at an optimum temperature of 290 °C toward its two individual compositions (ZnO nanocages (7.9) and ZnFe 2 O 4 nanospheres (8.1)). Moreover, the response of the ZnO/ZnFe 2 O 4 nanocages is even larger than that of other architectures, which follows the order hollow nanocages > double shell > hollow microsphere > hybrid hollow sphere > nanoparticle with rod. The remarkable gas sensing performance enhancement of ZnO/ZnFe 2 O 4 nanocages can be attributed to the unique porous and hollow structure, heterojunction and high response/surface area ratio.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 27
·期 5
·5153-5157
·
IF 1.798
Liu Lili,Li Shouchun,Guo Xin,Wang Lianyuan,Liu Li,Wang Xuesong
It has been reported a lot that nanowire and nanotube semiconductor oxide type sensor possess excellent sensing property. Many works ascribed excellent sensing properties to the big specific surface area. Herein, In 2 O 3 nanofiber and nanotube were synthesized by single nozzle electrospinning and followed by calcination with different heating rate. And the samples were characterized by scanning electron microscopy, and powder X-ray diffraction. Their gas sensing properties were studied to investigate the advantages of their morphologies, and the response and recovery dynamic curves were also tested to investigate their gas sensitive characteristics. The results show that acetone sensing sensitivity based on nanotubes is better than that of nanowires.
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高影响因子
ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Donghai Wu,Guanghua Lu,Ran Zhang,Qiuhong Lin,Jingjing Yao,Xinghou Shen,Wei Wang
In this study, ferrite modified carbon nanotubes (MFe 2 O 4 /CNTs, M: Fe, Mn) were prepared and employed as cathodic catalysts to assist electro-peroxone (i.e., combined ozonation with electrolysis process using a carbon-polytetrafluoroethylene cathode) treatment of emerging pollutant diatrizoate (DTZ) in aqueous solution. The structural and surface property of synthesized catalysts was studied, and the performance of electro-peroxone process using MFe 2 O 4 /CNTs based gas diffusion cathode (GDC) was systematically investigated from the kinetic and mechanistic viewpoints. Results show that the combination of ozonation and electrolysis exhibited synergistic degradation of DTZ. Approximately 71.9% DTZ had been degraded with MFe 2 O 4 /CNTs based GDC after 10 min, 13.2% higher than with bare CNTs based GDC, implying that the combined treatment efficiency could be enhanced by the presence of MFe 2 O 4 . The performance of MFe 2 O 4 /CNTs catalytic electro-peroxone process was positively correlated with inlet ozone concentration (10–30 mg/L), and an increase in applied current stimulated DTZ degradation at a low cathodic current density (5–40 mA/cm 2 ) but inhibited the degradation at a high cathodic current density (40–60 mA/cm 2 ). The MFe 2 O 4 /CNTs catalytic electro-peroxone treatment also showed a significant dependence on initial pH and reaction temperature, but was little affected by supporting electrolyte concentration. Higher removal efficiency was obtained at a lower initial DTZ concentration. The comparison tests reveal that peroxone reaction was the main pathway of hydroxyl radicals (HO ) production in the present system, and the presence of MFe 2 O 4 at the cathode could promote HO generation. These observations suggest that electro-peroxone is efficient for DTZ degradation in aqueous solution, and MFe 2 O 4 /CNTs are good and promising cathodic materials and catalysts for this process.
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高影响因子
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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高影响因子
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