溶胶-凝胶法制备Na_2WO_4^-Mn/SiO_2催化剂及其甲烷氧化偶联反应性能的研究  

Oxidative Coupling of Methane over Na_2WO_4-Mn/SiO_2 Catalysts Prepared by Sol-gel method

作　　者：王嘉欣[1] 丑凌军[1] 张兵[1] 杨建[1] 赵军[1] 李树本[1] 

机构地区：[1]中国科学院兰州化学物理研究所羰基合成与选择氧化国家重点实验室

出　　处：《天然气化工—C1化学与化工》2006年第2期1-5,共5页Natural Gas Chemical Industry

基　　金：国家自然科学基金面上项目(20373081)

摘　　要：采用溶胶-凝胶法制备了一系列5%Na2WO4-2%Mn/SiO2催化剂;用XRD、XPS、BET、O2-TPD和CO2-TPD等方法对催化剂进行了表征,并考察了对甲烷氧化偶联反应的催化性能。结果表明,与常规浸渍法相比,采用溶胶-凝胶法制备的Na2WO4-Mn/SiO2催化剂中W和Mn的原子浓度在催化剂表面和体相分布较为接近,而且两种制备方法所得的催化剂具有相似的催化性能,Na2WO4与α-方石英之间的相互作用,催化剂释放晶格氧的能力,碱性强弱是影响甲烷氧化偶联活性的关键因素。A series of 5wt% Na2WO4-2wt% Mn/SiO2 catalysts were prepared by sol-gel method. The structure and physical chemistry properties of these catalysts were characterized by XRD, XPS, BET, O2-TPD and CO2-TPD techniques, and their catalytic performances for the oxidative coupling of methane （OCM） were evaluated in a continuous micro-reactor. The results of X-ray diffraction （XRD） studies indicate that the main crystallite phases are Mn2O3, Na2WO4 and α-cristobalite, and the precursors of silica are transformed ultimately into highly crystallite α-cristobalite. O2-TPD, CO2-TPD and XPS results show that there is a synergic effect of lattice oxygen, basicity and elemental concentrations on surface, which is responsible to the high activity for the oxidative coupling of methane.

关 键 词：溶胶-凝胶法 Na2WO4-Mn/SiO2催化剂 甲烷氧化偶联 

分 类 号：O643.3[理学—物理化学]