摘要
通过共沉淀法制备了ZrO_2和Al_2O_3载体,采用等体积浸渍法制备了MoO_3质量分数为5%的Mo/ZrO_2和Mo/Al_2O_3催化剂,并用于甲烷化反应。在三种反应气氛下对两种预硫化的Mo基催化剂进行评价,发现ZrO_2载体均可显著促进甲烷化反应,同时能够促进水汽变换(WGS)反应。通过XRD、H_2-TPR、XPS和TEM等表征发现,两种载体上Mo物种的硫化程度以及暴露的活性位数量不同,从而导致两种催化剂上催化性能差异显著。与Mo/Al_2O_3相比,Mo/ZrO_2催化剂上的MoO_3更易被还原,硫化程度也更高,并且Mo^(4+)的含量更高,Mo6+的含量更低。虽然ZrO_2载体上MoS_2尺寸较大,边位置的Mo比例有所降低,但是由于MoS_2沿ZrO_2颗粒表面弯曲生长,使得MoS_2基面成为反应的活性位;因此,Mo/ZrO_2催化剂在甲烷化与WGS反应中表现出更优异的催化性能。
Mo/ZrO2 and Mo/Al2O3 catalysts with a MoO3 loading of 5% were prepared by incipient wetness impregnation method; the effect of support on the performance of Mo-based catalysts in methanation was then investigated in three different feeds. The results indicate that ZrO2 as a support can promote the methanation and water-gas shift（ WGS） reaction. ZrO2 is beneficial to the sulfuration and reduction of MoO3. The Mo sulfidation degree and the content of Mo4＋ on Mo/ZrO2 are higher than that on Mo/Al2O3. Besides,the curved MoS2 basal plane on Mo/ZrO2 can provide the active sites for methanation and WGS,which is effective to enhance the performance of Mo-based catalysts in methanation.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2017年第7期854-862,共9页
Journal of Fuel Chemistry and Technology
关键词
CO/CO2加氢
甲烷化
载体
硫化程度
CO/CO2 hydrogenation
methanation
oxide supports
sulfidation degree
