检索结果-南通市图书馆

Study on Highly Active Catalysts and a Once-Through Process for Methanol Synthesis from Syngas

Journal of Natural Gas chemistry 2003年第1期12卷 49-55页

作者： xin dong, bingshun shen, hongbin zhang, guodong lin, youzhu yuandepartment of chemistry, state key laboratory of physical chemistry for solid surfaces, xiamen university, xiamen 361.05, china Department of chemistry State Key Laboratory of Physical Chemistry for Solid Surfaces Xiamen University Xiamen 361005 China

Highly active CNT-promoted co-precipitated Cu-ZnO-Al_2O_3 catalysts,symbolized as Cu_iZn_jAl_k-x%CNTs, were prepared, and their catalytic activity for once-throughmethanol synthesis from syngas was investigated. The results illustrated that, under the reactionconditions (at 493 K, 5.0 MPa, the volume ratio of H_2/CO/CO_2/N_2= 62/30/5/3, GHSV= 4000 h^(-1),the observed single-pass CO-conversion and methanol-STY over a Cu_6Zn_3Al_1-12.5%CNTs catalystreached 64% and 1210 mg/(h-g), which was about 68% and 66% higher than those (38% and 730 mg/(h·g))over the corresponding CNT-free catalyst, Cu-6Zn_3Al_1, respectively. The characteristic studies ofthe catalysts revealed that appropriate incorporation of a minor amount of the CNTs into theCu_iZn_jAl_k brought about little change in the apparent activation energy of the methanol synthesisreaction, however, led to a considerable increase in the catalyst's active Cu surface area andpronouncedly enhanced the stationary-state concentration of active hydrogen-adspecies on the surfaceof the functioning catalyst, which would be favorable to increasing the rate of the COhydro-genation reactions. Moreover, the operation temperature for methanol synthesis over theCNT-promoted catalysts can be 10-20 degrees lower than that over the corresponding CNT-free contrastsystem, which would contribute considerably to an increase in equilibrium CO-conversion andCH_3OH-yield.

关键词： carbon nanotubes Cu_iZn_jAl_k-x%CNTs catalyst methanol synthesis CO/CO_2 hydrogenation syngas

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

CHOLESTERIC LIQUID CRYSTALlinE CHARACTER ON THE SURFACE OF CHITOSAN/POLYACRYLIC ACID COMPOSITES

引用

Chinese Journal of Polymer Science 2001年第3期19卷 247-253页

作者： Yan-ming dong Yu-song Wu Mian Wang Department of Materials Science & state key laboratory for physical chemistry of solid surfaces, xiamen university xiamen 361.05, china xiamen Univ Dept Mat Sci Xiamen 361005 Peoples R China xiamen Univ State Key Lab Phys Chem Solid Surfaces Xiamen 361005 Peoples R China

The cholesteric liquid crystalline structure in chitosan/polyacrylic acid composite films was studied by surface techniques. A periodical lamellar-like structure was observed in the permanganic acid etched film surface by both scanning electron microscopy (SEM) and atomic force microscopy (AFM), instead of the thumb-print texture which can be detected with polarized optical microscopy. It is suggested that the periodical lamellar-like structure is induced by the etching selectivity between cholesteric layers due to different molecular arrangement on the film surface. Four kinds of perpendicular disclinations, i.e. chi --> tau (-) + lambda (+), chi --> lambda (-) + tau (+), chi --> tau (-) + tau (+) and chi --> lambda (-) + lambda (+) were found in the composite films from SEM observations. The smallest periodicity of lamellar-like structure (equals to half pitch) is 20 similar to 40 nm measured with AFM.

关键词： chitosan cholesteric order liquid crystalline fingerprint texture lamellar structure SEM AFM

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An Ab Initio Study of N_2O Decomposition on MgO Catalyst

引用

Chinese Chemical Letters 1998年第6期9卷 583-586页

作者： xin LU xin XU Nan Qin WANG and Qian Er zhang(state key laboratory for physical chemistry of solid surfaces, Institute of physical chemistry,Department of chemistry, xiamen university, xiamen 361.05) xiamen Univ Dept Chem State Key Lab Phys Chem Solid Surfaces Inst Chem Phys Xiamen 361005 Peoples R China

Ab initio calculations based on density functional theory have been used to study thedecompsition of N_2O on MgO. The reaction is predicted to occur on O_3c and O_(4c) atoms, but not onO_(5c) atoms, with an activation barrier of 25-27 kcal/mol, in agreement with the experimental valueof 35 kcal/mol. Natural bond orbital analysis shows that the reaction leaves O ad-atoms on thosesurface O anions to form a peroxide-like 'O^2_(2-)' species. The )O-O bond stretching frequency ispredicted to be in the range from 820 cm(-1) to 825 cm(-1).

关键词： Ab initio calculation N_2O decomposition MgO catalyst

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

SYNTHESIS OF POLYCATECHOL WITH ELECTROCHEMICAL ACTIVITY AND ITS PROPERTIES

引用

Chinese Journal of Polymer Science 2002年第6期20卷 517-524页

作者： Yong Kong Shao-lin Mu Bing-wei Mao Department of chemistry School of Sciences, Yangzhou university Yangzhou 225002, china state key laboratory of physical chemistry of the solid Surface, xiamen university,xiamen 361.05, china Yangzhou Univ Sch Sci Dept Chem Yangzhou 225002 Peoples R China xiamen Univ State Key Lab Phys Chem Solid Surface Xiamen 361005 Peoples R China

The electrochemical polymerization of catechol on platinum has been carried out using repeated potential cycling between -0.2 and 1.1 V (versus SCE). The electrolytic solution consisted of 0.2 mol dm(-3) catechol, 0.5 mol dm(-3) NaCl and 0.1 mol dm(-3) Na2HPO4 with pH 8.72. Catechol can not be polymerized at pH greater than or equal to 10.12. Polycatechol has an electrochemical lactivity at pH less than or equal to 4. The anodic and cathodic peak potentials of polycatechol shift towards more negative values as the pH of the solution increases from 1 to 4. The electrochemical activity of polycatechol hardly changes in this pH region, but it decreases slowly with time. This is caused by oxygen in air, which leads to an irreversible oxidation of polycatechol. This property is favorable for protecting metals from corrosion. Raman and FTIR spectra of polycatechol and catechol are quite different. AFM images of polycatechol films provide evidence that the image of the oxidized state of polycatechol is markedly different from that of the reduced one. This difference is caused by doping and dedoping of polycatechol.

关键词： catechol polycatechol electrochemical activity Raman spectra FTIR spectra AFM images

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A simple solvothermal route towards the morphological control of ZnO and tuning of its optical and photocatalytic properties

引用

Science china chemistry 2010年第8期53卷 1711-1717页

作者： JIANG YaQi,LI FangFang,SUN Ran,XIE ZhaoXiong & ZHENG LanSun state key laboratory for physical chemistry of solid surfaces Department of chemistry,College of chemistry and Chemical Engineering,xiamen university,xiamen 361.05,china 1. state key laboratory for physical chemistry of solid surfaces Department of chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China

ZnO nanoparticles with different morphologies were solvothermally synthesized by controlling the alkali (sodium hydroxide) concentration in an isopropanol *** products were characterized by means of powder X-ray diffraction,UV-visible absorption spectra,scanning electron microscopy,transmission electron microscopy,and selected area electron *** morphologies of the formed ZnO nanocrystals were dependent on the concentration of the alkali,and with increases of sodium hydroxide concentration,the ZnO nanocrystals evolved from rod to hexagonal bipyramid,and then to a flower-like *** flower-like nanostructure resulted from the etching of the hexagonal bipyramid by the excess *** photoluminescence and photocatalytic properties of the prepared ZnO were *** difference of green emission among the ZnO nanocrystals indicated that a higher sodium hydroxide concentration led to a higher level of *** size,the surface structure and defects in the ZnO nanocrystals affected its photo-degradation characteristics.

关键词： zinc oxide solvothermal method nanocrystal photoluminescence photocatalysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Controllable incorporation of CdS nanoparticles into TiO_2 nanotubes for highly enhancing the photocatalytic response to visible light

引用

Science china chemistry 2009年第12期52卷 2148-2155页

作者： WANG Chenglin1,SUN Lan1,XIE KunPeng1 & lin ChangJian1,2 1 Department of chemistry,College of chemistry and Chemical Engineering,xiamen university,xiamen 361.05,china 2 state key laboratory of physical chemistry of solid surfaces,xiamen university,xiamen 361.05,china 1. Department of chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China 2. state key laboratory of physical chemistry of solid surfaces Xiamen University Xiamen 361005 China

A constant current electrochemical deposition was employed to incorporate CdS nanoparticles into the TiO2 nanotube arrays (TiO2NTs). The size and amount of CdS nanoparticles in TiO2NTs (CdS@TiO2NTs) were controllable via modulating current,deposition time and electrolyte concentration. It was revealed,from the scanning electron microscopy (SEM) images and X-ray photoelectron spectroscopy (XPS) in depth profile,that CdS nanoparticles were filled into TiO2 nanotubes. A shift of the absorption edge toward the visible region under the optimal electrodeposition condition was observed with the diffuse reflectance spectroscopy (DRS). A 5-fold enhancement in the photocurrent spectrum for TiO2NTs was observed and the photocurrent response range was significantly extended into the visible region because of the CdS incorporation. Compared with pure TiO2NTs,under a visible light irradiation,CdS@TiO2NTs exhibited a 3.5-fold improvement of photocatalytic activity,which was demonstrated by the photocatalytic decomposition of Rhodamine B (RhB).

关键词： TiO2 nanotube CdS photocatalysis RhB

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Novel Ru - K/Carbon Nanotubes Catalyst for Ammonia Synthesis

引用

Chinese Chemical Letters 2000年第4期11卷 373-374页

作者： Yun CAI Jing dong lin Hong Bo CHEN Hong Bin zhang Guo dong lin Dai Wei LIAO (state key Lab of physical chemistry on solid surfaces. Department of chemistry Institute of physical chemistry. xiamen university, xiamen 361.05) xiamen Univ Inst Phys Chem Dept Chem State Key Lab Phys Chem Solid Surfaces Xiamen 361005 Peoples R China

A novel ammonia synthesis catalyst, potassium-promoted ruthenium supported on carbon nanotubes, was developed. It was found that the Ru-K/carbon nanotubes catalyst had higher activity for ammonia synthesis (20.85 ml NH3/h/g-cat) than the Ru-K/fullerenes ( 13.3 ml NH3/h/g-cat) at atmospheric pressure and 623 K. The catalyst had activity even at 473 K, and had the highest activity( 23.46 ml NH3/h/g-cat) at 643 K. It was suggested that the multi-walled structure favored the electron transfer, the hydrogen-storage and the hydrogen-spill which were favorable to ammonia synthesis.

关键词： ammonia synthesis ruthenium carbon nanotubes

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The　Active　Oxygen　Species　for　Oxidative　Coupling　of　Methane　over　CeO_2/BaF_2　Catalyst　by　in　Situ　Confocal　Microprobe　Raman　Spectroscopy

引用

Chemical Research in Chinese Universities 1997年第1期13卷 93-95页

作者： LONG Rui qiang and WAN Hui lin (Department of chemistry and state key laboratory for physical chemistry of the solid Surface, xiamen university, xiamen, 361.05) xiamen UNIV DEPT CHEMXIAMEN 361005PEOPLES R CHINA xiamen UNIV STATE KEY LAB PHYS CHEM SOLID SURFACEXIAMEN 361005PEOPLES R CHINA

ＴｈｅＡｃｔｉｖｅＯｘｙｇｅｎＳｐｅｃｉｅｓｆｏｒＯｘｉｄａｔｉｖｅＣｏｕｐｌｉｎｇｏｆＭｅｔｈａｎｅｏｖｅｒＣｅＯ２／ＢａＦ２ＣａｔａｌｙｓｔｂｙｉｎＳｉｔｕＣｏｎｆｏｃａｌＭｉｃｒｏｐｒｏｂｅＲａｍａｎＳｐｅｃｔ... 详细信息

ＴｈｅＡｃｔｉｖｅＯｘｙｇｅｎＳｐｅｃｉｅｓｆｏｒＯｘｉｄａｔｉｖｅＣｏｕｐｌｉｎｇｏｆＭｅｔｈａｎｅｏｖｅｒＣｅＯ２／ＢａＦ２ＣａｔａｌｙｓｔｂｙｉｎＳｉｔｕＣｏｎｆｏｃａｌＭｉｃｒｏｐｒｏｂｅＲａｍａｎＳｐｅｃｔｒｏｓｃｏｐｙ＊＊Ｓｕｐｐｏｒｔｅ...

关键词： Oxygen species Oxidative coupling Methane In situ Raman spectroscopy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Studies on Catalysis in Partial Oxidation of Methane to Syngas(Ⅰ)──Performance and Characterization of Ni-based Catalysts

引用

Chemical Research in Chinese Universities 1996年第1期12卷 70-80页

作者： CHEN Ping zhang Hong-bin lin Guo-dong and TSAI Khi-rui (Department of chemistry &. state key laboratory for physical chemistry of the solid Surface, xiamen university, xiamen, 361.05) xiamen UNIV DEPT CHEMXIAMEN 361005PEOPLES R CHINA xiamen UNIV STATE KEY LAB PHYS CHEM SOLID SURFACEXIAMEN 361005PEOPLES R CHINA

Highly active and selective Ni-based catalysts for partial oxidation of methane (POM) to syngas (CO/H,) have been studied and developed. Spectroscopic characterization by XRD, XPS, EPR, etc. demonstrated that under the POM reaction conditions, the Ni-components of the catalysts investigated were reduced and enriched on the surface to form metallic Ni0-phase. A comparative study of the first series of transition-metals showed that only Ni and Co have a high POM activity and selectivity, whereas the others (including Mn, Fe, Cu, etc. ) give mainly complete combustion products, Co, and H2O. The results favor the following viewpoints: the PoM activity is related with the rapidly changeable valence transitionmetal sites, M0/M2+ (e. g. Ni0/Ni2+ ), on the surface of the functioning catalysts;the transition-metal sites in zero-valence state seem to be responsible for the activation and dehydrogenation of methane by homolytic splitting of its C-H bonds on these sites. and the nature of rapidly changeable valence of the active sties is requisite for activation and rapid conversion of dioxygen.

关键词： Partial oxidation of methane Syngas Ni-based catalysts

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Studies of Catalysis in Partial Oxidation of Methane to Syngas（Ⅱ）──Chemisorbed Species，Energetics and Mechanism

引用

Chemical Research in Chinese Universities 1995年第4期11卷 323-335页

作者： CHEN Ping zhang Hong-bin lin Guo-dong andTSAI Khi-rui(Department of chemistry &state key laboratory for physical Chemistyry of the solid Surface ,xiamen university ,xiamen 361.05) xiamen UNIV DEPT CHEMXIAMEN 361005PEOPLES R CHINA xiamen UNIV STATE KEY LAB PHYS CHEM SOLID SURFACEXIAMEN 361005PEOPLES R CHINA

he characteristic study,by means of in-situ IR spectroscopy, of chemisorbed species on the Ni-catalysts for the partial oxidation of methane(POM)to syngas demonstrated the existence of CH_x(a)and H_xCO(a)adspecies on the functioning Ni-catalysts, Several designed experimental investigations on the reactivities of methane with CO_2 and with O_2,respectively,over the Ni-catalysts, and of CO_2 with the prereduced Ni-catalyst,ats well as of the deposited carbon with CO_2 and with O_2,respectlvely,liave been carried out and the reLqults were unfavorable to the two-step mechanistic interpretation proposed for the POM reaction. By means of tlie BOC-MP Approach,energetics of a set of elementary reactions,which may be involved in the POM process,on the clean(111)surface of Ni,Fe,Cu and Pd, re- spectively,has been *** result;of the experiments and the calculation of the present work favor the direct catalytic dissociation-plus-surface oxidation-plus-further debdrogenation mechanism as the dominant pathway making major contribution to the POM reaction.

关键词： Partial oxidation of methane Syngas Chemisorbed species Energetics. Mechanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：