检索结果-南通市图书馆

selective oxidation mediated synthesis of unique SexTey nanotubes, their assembled thin films and photoconductivity

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第2期11卷 665-675页

作者： Yang, Yuan Liu, Guo-Qiang Gao, Min-Rui Xia, Yu Yu, Shu-Hong Division of Nanomaterials and Chemistry Hefei National Laboratory for Physical Sciences at the Microscale Collaborative Innovation Centre of Suzhou Nano Science and Technology CAS Centre for Excellence in Nanoscience Department of Chemistry Hefei Science Centre of CAS University of Science and Technology of China Hefei China

One-dimensional hollow nanostructures have potential applications in many fields and can be fabricated using various methods. Herein, a selective-oxidation route for the synthesis of unique SexTey nanotubes （STNTs） with a controlled morphology using TexSey@Se core-shell nanowires （TSSNWs） as a template is reported. Because of the lower redox potential of TeO2/Te compared to that of H2SeO3/Se, the Te in TSSNWs can be preferentially oxidized by an appropriate oxidant of HNO2 to form STNTs. The inner diameters and wall thicknesses of the STNTs can be tuned by modulating the core diameters and shell thicknesses of the TSSNWs, respectively. The STNTs can be assembled into a monolayer composed of well-arranged nanotubes using the Langmuir-Blodgett technique. A device based on films stacked with 10 STNT monolayers was fabricated to investigate the photocoductivity of the STNTs. The STNTs exhibited a good photoresponse over the whole ultraviolet-visible spectrum, revealing their votential for application in ovtoelectronic devices.

关键词： selective oxidation core-shell nanowires nanotubes assembled thin films photoconductivity

selective oxidation of methane to formaldehyde by oxygen over silica-supported iron catalysts

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2009年第3期18卷 288-294页

作者： Jieli He Yang Li Dongli An Qinghong Zhang Ye Wang State Key Laboratory of Physical Chemistry of Solid Surfaces National Engineering Laboratory for Green Chemical Productions of Alcohols Ethers and Esters College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 Fujian China

FeOx-SiO2 catalysts prepared by a sol-gel method were studied for the selective oxidation of methane by oxygen. A single-pass formaldehyde yield of 2.0% was obtained over the FeOx-SiO2 with an iron content of 0.5 wt% at 898 K. This 0.5 wt% FeOx-SiO2 catalyst demonstrated significantly higher catalytic performances than the 0.5 wt% FeOx/SiO2 prepared by an impregnation method. The correlation between the catalytic performances and the characterizations with UV-Vis and H2-TPR suggested that the higher dispersion of iron species in the catalyst prepared by the sol-gel method was responsible for its higher catalytic activity for formaldehyde formation. The modification of the FeOx-SiO2 by phosphorus enhanced the formaldehyde selectivity, and a single-pass formaldehyde yield of 2.4% could be attained over a P-FeOx-SiO2 catalyst （P/Fe = 0.5） at 898 K. Raman spectroscopic measurements indicated the formation of FePO4 nanoclusters in this catalyst, which were more selective toward formaldehyde formation.

关键词： selective oxidation methane formaldehyde iron catalyst sol-gel method

selective oxidation of propane to acrylic acid over mixed metal oxide catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2008年第2期17卷 191-194页

作者： Wei Zheng Zhenxing Yu Ping Zhang Yuhang Zhang Hongying Fu Xiaoli Zhang Qiquan Sun Xinguo Hu School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150001 Heilongjiang China Daqing Petroleum Co Ltd Daqing 163453 Heilongjiang China

The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio （Mo1V0.31Te0.23Nb0.12）. The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H8 ：O2 ： H2O ： N2 = 4.4： 12.8 ： 15.3 ： 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.

关键词： propane oxidation catalysts preparation acrylic acid selective oxidation

selective oxidation of Methane to Methanol Using Molecular Oxygen on MoOx/(LaCoO3+Co3O4)Catalysts

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2003年第10期14卷 1066-1069页

作者： Xin ZHANG, De Hua HE, Qi Jiang ZHANG, Bo Qing XU, Qi Ming ZHUState Key Laboratory of C1 Chemistry and Technology, Department of Chemistry, Tsinghua University, Beijing 100084 State Laboratory of C1 Chemistry and Technology Department of Chemistry Tsinghua University

Comparatively high CH3OH selectivity (60.0%) and yield (6.7%) were obtained on MoOx/(LaCoO3+Co3O4) catalysts in selective oxidation of methane to methanol using molecular oxygen as oxidant. The interaction between MoOx and La-Co-oxide modified the molecular structure of molybdenum oxide and the ratio of O7O ' on the catalyst surface, which controlled the catalytic performance of MoOx/(LaCoO3+Co3O4) catalysts.

关键词： Methane selective oxidation methanol molybdenum oxide species O-/O2- ratio.

selective oxidation of Propane over CsFePVAsMo Heteropoly Compound Catalyst

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2004年第8期22卷 831-836页

作者：蔡铁军余长林邓谦彭振山龙云飞吕晓萌 Department of Chemistry & Chemical Engineering Hunan University of Science & Technology Xiangtan Hunan411201 China

Both the partially reduced and non-reduced multi-component heteropoly compound catalysts with Keggin structure were prepared and used for the selective oxidation of propane. The catalysts were characterized by IR, H2-TPR, NH3-TPD, SEM and XRD. The addition of Cs increased the selectivity of acrylic acid and acetic acid. The selective oxidation performance was greatly improved with the addition of As. Among all of the tested catalysts, the catalytic performance of the Cs1.8Fe0.16HxPVAs0.4Mo11O40 (non-reduced) was the best and the maximum yield of acrylic acid reached 16.42%.

关键词： heteropoly compound partially reduced selective oxidation propane acrylic acid

selective oxidation of Isobutane over NH_4CsFePVMoAs Heteropolycompound Catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2005年第1期14卷 54-60页

作者： TiejunCai ZhengjunFang QianDeng ZhenshanPeng DepartmentofChemistryandChemicalEngineering HunanUniversityofScienceandTechnologyXiangtan411201China

A series of NH_4Cs_(1.5)Fe_(0.08)H_xPVMo_(11)As_aO_y heteropolycompoundcatalysts for the selective oxidation of isobutane, having Keggin structure, were synthesized byusing co-precipitation method. The catalysts were characterized by FT-IR, H_2-TPR, TG-DTA, SEM andXRD. Effects of the As content, reaction time, reaction temperature and molar ratio of isobutane tooxygen in feedstock on the activity and selectivity of the catalyst were investigated. Theactivation energy of the catalysts was measured by kinetics researches. Results showed theintroduction of Cs^+ into the catalysts shortened the stable period of them and enhanced theircatalytic activity for the selective oxidation of isobutane. The highest conversion of isobutane andthe total selectivity to liquid products were 18.6% and 81.2%, respectively, which were obtained at380℃ with a space velocity of 975 h^(-1) over the NH_4Cs_(1.5)Fe_(0.08)H_xPVMo_(11) As_(0.3)O_yheteropolycompound catalyst. It is confirmed that completely oxidized products were controlled well.

关键词： heteropolycompound catalyst isobutane selective oxidation methacrylicacid methacrolein

selective oxidation of n-Butane over VPO Catalyst Modified by Different Additives

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2005年第3期14卷 177-180页

作者： Hong Liang Daiqi Ye School of Biological and Chemical Engineering Guangzhou University Guangzhou 510091 China School of Chemical Engineering South China University of Technology Guangzhou 510640 China

A series of vanadyl pyrophosphate catalyst （VPO） modified by different additives have been prepared with the aim to study the performance for selective conversion of n-butane to maleic anhydride（MA）. The addition of various promoters improved the catalytic performance remarkably on both activity and selectivity. The correlation of activity and selectivity of the catalysts with their structure has been discussed. The increase in BET surface areas and surface redox sites leads to an enhanced activity. However, good selectivity can only be obtained on those surfaces with suitable surface acid sites.

关键词： vanadyl pyrophosphate catalyst additives selective oxidation maleic anhydride

Ti-modified Mesoporous Molecular Sieves Containing both selective oxidation and Photocatalysis Centers

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2004年第4期20卷 386-391页

作者： GUOZong-ying HEJing DavidG.Evans DUANXue ZHUYue-xiang XIAOTian-cun TheKeyLaboratoryofScienceandTechnologyofControllableChemicalReactionsofMinistryofEducation BeijingUniversityofChemicalTechnologyBeijing100029P.R.China StateKeyLaboratoryforStructuralChemistryofUnstableandStableSpecies CollegeofChemistryandMolecularEngineeringPekingUniversityBeijing100871P.R.China InorganicChemistryLaboratory OxfordUniversityOX13QRUK

Mesoporous molecular sieves possessing high mesopore volumes and large specific surface areas were prepared and characterized by means of XRD, low temperature N_2 adsorption-desorption measurements, FT IR, Raman, UV-visible diffuse reflectance and XPS spectroscopy. The materials contain both framework and extra-framework Ti centers which exhibit selective oxidation catalytic activity and photocatalytic activity respectively. The catalysis of selective oxidation was studied with the hydroxylation of benzene with hydrogen peroxide and photochemical activity was studied by the yields of ·OH and H_2O_2, respectively.

关键词： Ti-modified mesoporous materials Framework sites Non-framework sites selective oxidation Photocatalysis

selective oxidation of Isobutene over CsFeCoBiMnMoO_x Mixed Oxide Catalyst

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2004年第3期13卷 172-176页

作者： ZhenshanPeng ChanglinYu TiejunCai QianDeng DepartmentofChemistryandChemicalEngineeing HunanUniversityofScienceandTechnologyXiangtan411201China

Mixed oxide catalyst Cs0.1Fe2Co6BiMnMo12Ox was prepared by the coprecipitation method. selective oxidation of isobutene was carried out in a fixed-bed reactor over Cs0.1Fe2Co6BiMnMo12Ox. The results showed that the catalyst had high catalytic activity. Under the optimum reaction conditions (n(i-C4=):n(O2)=1:2-1:4, space velocity=180 h-1, T=360℃), the yields of methacrolein and methacrylic acid can reach 80% and 8%, respectively. The total yield of liquid products (methacrolein, methacrylic acid and acetic acid) can reach about 90%.

关键词： mixed oxide isobutene selective oxidation methacrolein methacrylic acid