8 research outputs found
In situ Time-resolved FTIR and Raman Characterizations of the Partial Oxidation of Methane to Synthesis Gas over Ir/SiO_2 Catalyst
[中文文摘]采用原位时间分辨红外光谱和原位显微Raman光谱技术对Ir/SiO2 上甲烷部分氧化 (POM)制合成气反应的初级产物和反应条件下催化剂表面物种进行了跟踪考察 ,实验结果表明 ,在H2 预还原的新鲜Ir/SiO2 表面 ,CO是V(CH4)∶V(O2 )∶V(Ar) =2∶1∶45混合气反应的初级产物 ,因而甲烷的直接氧化过程是CO生成的主要途径 ;而在稳态反应条件下 ,CO生成的途径可能主要来自CO2 和H2 O与催化剂表面积碳物种 (CHx)和 /或CH4的反应 .催化剂上生成的积碳可能是导致稳态条件下Ir/SiO2 上POM反应机理不同于H2 预还原的新鲜催化剂的主要原因。[英文文摘]In situ time-resolved FTIR and in situ microprobe Raman spectroscopies were used to follow the primary products as well as the surface and gas phase species formed during the reaction of partial oxidation of methane (POM) to synthesis gas over Ir/SiO 2 catalyst. The results suggested that direct oxidation of CH 4 to CO is the dominant pathway of POM reaction over the freshly reduced Ir/SiO 2 catalyst, while the dominant schemes of CO formation over the catalyst under the steady state reaction condition are probably via the reactions of CO2 and H2O with the deposited carbon species (CHx) and/ or CH4 . The mechanistic difference between the POMto synthesis gas over freshly reduced Ir/ SiO2 catalyst and the catalyst under the steady state reaction may have resulted from the formation of significant amount of deposited carbon species in the latter system.国家重点基础研究发展规划 (No.G1999022408); 国家自然科学基金(No.20021002)资助项目
Mechanistic Study of the Partial Oxidation of the Methane to Synthesis Gas over SiO2- and Al2O3-Supported Rh, Ru and Ir Catalysts
本文以探明SiO2负载的Rh、Ru、Ir催化剂上甲烷部分氧化(POM)制合成气的反应机理及其差异本质以及焙烧温度对Rh/Al2O3催化剂POM反应性能的影响为主要目的。首先采用低温N2吸附、H2(或O2、CO)化学吸附、XRD、XPS、程序升温(H2-TPR、O2-TPD、TPSR)等实验技术对相关催化剂进行了表征,并对催化剂的POM反应性能进行了详细考察。在此基础上采用原位时间分辨红外光谱、原位拉曼光谱、CH4脉冲、瞬时产物分析技术等对各贵金属催化剂上POM反应的初级产物、反应条件下活性金属的价态和催化剂表面的碳物种以及催化剂的亲氧能力进行了考察。实验结果表明,在还原态Rh/SiO2上,CO...The present work focuses on the studies of the mechanism of the partial oxidation of methane (POM) to synthesis gas over SiO2-supported Rh, Ru, Ir catalysts and the effect of calcination temperatures on the catalytic performance of Rh/Al2O3 for POM to synthesis gas. The catalysts were characterized by N2 adsorption at low temperature, H2 (or O2, CO) chemisorption, XRD, XPS and temperature-programm...学位:理学博士院系专业:化学化工学院化学系_物理化学(含化学物理)学号:B19992501
甲烷在Ni/TiO_2催化剂表面的活化
考察了Ni/TiO2催化剂甲烷部分氧化和二氧化碳重整制合成气的反应活性,实验表明,以TiO2为载体的镍系催化剂对于甲烷部分氧化制合成气反应具有较好的活性,尤其对H2的选择性较高,对二氧化碳重整制合成气反应具有较好的低温反应活性.采用脉冲-质谱在线分析等技术,在无气相氧条件下向Ni/TiO2催化剂脉冲CH4,发现甲烷在催化剂表面的活化(转化)及其氧化产物的选择性与金属催化剂表面氧的浓度密切相关.CH4与Ni/TiO2催化剂作用过程中存在明显的氢溢流和氧溢流现象,可能是这种溢流效应使得N/TiO2催化剂具有良好的反应活性和抗积碳性能
Rh/SiO_2催化剂上甲烷部分氧化制合成气反应机理的研究(英文)
运用TPSR、TR-FTIR和化学捕获技术(CH3I作捕获剂),探讨了Rh/SiO2催化剂上的POM反应机理,由此提出热分解氧化机理,认为CHx(x=1~3)和CHxO(x=1~3)可能是反应物种
甲烷部分氧化制合成气反应中催化剂积炭的研究(英文)
Ni/Al_2O_3催化剂上甲烷部分氧化制合成气反应是在固定床流动反应装置上进行的。考察了催化剂的床层温度、反应压力、空速和原料气配比对催化剂积炭产生的影响。实验结果表明,积炭速率随催化剂床层温度的升高而降低,当温度低于70℃时,积炭速率骤增:积炭总是发生在催化剂床层的下段;若空速超过3.0×10~5h~(-1),积炭速率随空速增加而明显降低。从FTIR实验结果可知,吸附在Ni/Al_2O_3催化剂表面上的CO,一部分歧化生成了CO_2和C。综上所述,催化剂表面积炭主要来源于以下两个反应: 2CO→C+CO_2,CO+H_2 = C+H_2
带隙法测定SiGe/Si材料的应变状态
从固体模型理论的结果出发,计算了生长于Si(100)衬底上x值小于0.85的Si1-xGex合金材料(能带结构为类蛳结构)的间接带隙与应变的关系,结果表明,应变的SiGe材料的带隙和完全弛豫状态下材料的带隙之差与应变呈线性关系.基于这一结果,提出了用测量带隙来间接测定SiGe/Si应变状态的方法.用带隙法和x射线双晶衍射法测量了不同应变状态下的SiGe/Si多量子阱材料的应变弛豫度,两者可以较好的符合,表明带隙法测量SiGe应变弛豫度是可行的
Activation of methane over Ni/TiO2 catalyst
The reactions of methane partial oxidation (POM) and methane reforming with CO2 to produce synthetic gas over Ni/TiO2 catalyst were studied. The catalyst shows good catalytic performance with high H-2 selectivity for the POM reaction and good low temperature activity for the reaction of methane reforming with CO2. The activation of methane over Ni/TiO2 catalysts was investigated using MS-pulse technique in the absence of gaseous oxygen. It was found that methane activation and its oxidation products were determined by the concentration of surface oxygen species of the catalyst. Both oxygen and hydrogen spillover phenomena were observed during the interaction of methane with Ni/TiO2. The spillover oxygen and hydrogen species over the catalyst may be responsible for the good activity and carbon resistance ability of the Ni/TiO2 catalyst
The Window of the City in the Opening Times:A Review of the Design of Guiyang Longdongbao International Airport Terminal 2
2014年6月7—8日,由新建筑杂志社、当代中国建筑创作论坛学术委员会、贵州省建筑设计研究院、中国民航机场建设集团公司联合举办的“贵阳·新建筑论坛“在贵阳市铂尔曼酒店举行。7日上午,在设计方的带领下与会嘉宾参观了论坛品评对象——贵阳龙洞堡国际机场T2航站楼,下午围绕论坛主题“开放时代的城市窗口“展开品谈。会上围绕航站楼建筑设计创作中的理念、技术以及整体环境的空间和景观体验等方面问题进行了深入探讨,总结了T2航站楼在设计建造过程中的问题,对其建筑设计创作水平给予了较高评价