摘要
采用硝酸铝和硝酸钴的乙醇溶液与钼酸铵的碳酸铵水溶液共沉淀制备了Al2O3负载Co-Mo双金属氧化物前驱体,结合氨程序升温还原法制得了氮化物催化剂Co-Mo-N/Al2O3.利用X射线衍射和N2物理吸附方法表征了制备的前驱体和钝化态Co-Mo-N/Al2O3催化剂的晶相和孔结构,用程序升温脱附、程序升温表面反应及扫描电子显微镜考察了共沉淀法和浸渍法制备的催化剂的晶格稳定性、活性中心和表面形貌,用氨分解反应表征了Co-Mo-N/Al2O3催化剂的活性.结果表明,焙烧温度对催化剂比表面积有较大影响,低温焙烧的样品中活性组分散性较好,673K焙烧制得催化剂的氨分解活性最高.与浸渍法制备的Co-Mo-N/Al2O3催化剂相比,共沉淀法制备的催化剂具有更高的晶格稳定性、更均匀的活性组分分布和更高的氨分解活性.
The alumina-supported Co-Mo bimetallic oxide precursor was prepared by coprecipitation of ethanolic solution of Al（NO3）3 and Co（NO3）2, and aqueous solution of （NH4）2CO3 and （NH4）6Mo7O24. The Co-Mo bimetallic nitride catalyst Co-Mo-N/Al2O3 was synthesized by the NH3 temperature-programmed reaction based on the prepared oxide precursor. X-ray diffraction and N2 physical adsorption were used to investigate the effect of calcination temperature on the phase and structural parameters of the catalyst. Temperature-programmed desorption, temperature-programmed surface reaction, and scanning electron microscopy were used to study the crystal stability, properties of active sites, and the surface morphology of the catalysts prepared by the coprecipitation method and impregnation method. The results indicated that the BET surface area of the samples was highly dependent upon the calcination temperature. The Co-Mo active components were dispersed more uniformly in the samples calcined at low temperature. The highest catalytic activity for ammonia decomposition was obtained from the sample calcined at 673 K. Compared with the sample prepared by impregnation, the Co-Mo-N/Al2O3 catalyst prepared by coprecipitation has higher activity, higher crystal stability, and more uniform dispersion of the active comoonents.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第7期613-618,共6页
基金
浙江省教育厅资助项目(Y200805843)
关键词
钴
钼
氧化铝
氨分解
共沉淀法
浸渍法
cobalt
molybdenum
alumina
ammonia decomposition
coprecipitation method
impregnation method
