摘要
于不同温度(350℃、450℃、550℃和650℃)焙烧(NH4)6Mo7O24.4H2O,制得不同晶型的MoO3,以其为前驱体程序升温碳化制备了一系列的Mo2C催化剂,用于催化甲烷二氧化碳重整制合成气的反应进行活性评价。并通过热重分析、X射线衍射分析和程序升温还原等表征,讨论了MoO3的晶型与所制备的Mo2C的体相和催化剂性能的关系。结果表明,350℃和450℃焙烧(NH4)6Mo7O24.4H2O可制得较为单一的正斜方晶结构的α-MoO3,α-MoO3通过范德华力连接的层状结构有利于在程序升温碳化过程中由CH4/H2分解产生的活泼氢和活泼碳插入层间,促进了Mo2C的生成,进而催化性能较佳。
MoO3 in different crystal forms was obtained by calcination of （NH4 ）6Mo7O24.4H2O at different temperature （350 ℃, 450 ℃, 550 ℃ and 650 ℃ ）. Mo2C was prepared by temperature-programmed carbonization using these MoO3 as the precursors and characterized by XRD, TPR and thermal analysis （TG, DTG and DTA）. Catalytic behaviors of the as-prepared Mo2C were tested using CH4-CO2 reforming （dry methane reforming, DMR） to synthesis gas as the probe reaction. Effects of the crystal forms of MoO3 on DMR activity of MOEC were discussed. Solely orthorhombic-structure α-MoO3 was obtained via calcinations of （NH4 ）6Mo7O24.4H2O at 350 ℃ and 450 ℃, with unique layered structure, in which the layers were bound together by weak van der Waals forces. The layered structure facilitates insertion of the active hydrogen and active carbon produced from decomposition of CH4/H2 into the layers during temperature-programmed carbonization and thus favored formation of Mo2C with good catalytic properties.
出处
《工业催化》
CAS
2010年第1期50-53,共4页
Industrial Catalysis
基金
国家重点基础研究发展计划(973计划)(2005CB221204)
国家自然科学基金(20576085)
关键词
能源化学
MoO3晶型
Mo2C
甲烷二氧化碳重整
energy chemistry
MoO3 crystal form
molybdenum carbide （Mo2C）
CH4-CO2 reforming （dry methane reforming）
