焙烧温度对负载型Mo基催化剂结构与甲烷化性能的影响

Effect of calcination temperature on structure and methanation performance of supported Mo catalyst

以浸渍法制备得到的CeO2-Al2O3复合氧化物载体于500℃或700℃焙烧处理,浸渍Co和Mo物种后得到Co-Mo/(CeO2-Al2O3)催化剂前驱体,再于500℃或700℃进行焙烧处理得到催化剂。采用N2物理吸附、H2程序升温还原、X射线衍射及扫描电子显微镜对催化剂进行了表征,在固定床上于550℃,3MPa,5000h-1,n(H2)/n(CO)为1.0且含有H2S的合成气中对催化剂的甲烷化性能进行了测试。结果表明CeO2-Al2O3载体的焙烧温度对催化剂比表面积有较大影响,而催化剂表面Co与Mo物种的分散度主要受催化剂前驱体焙烧温度的影响。当CeO2-Al2O3载体于500℃焙烧催化剂前驱体于700℃焙烧后,Co与Mo物种的分散度最好,催化剂甲烷化活性最高。

CeO2-Al2O3 supports prepared by impregnation were calcinated at 500℃ or 700℃, then loaded with Co and Mo by impregnation, and the obtained Co-Mo/（CeO2-Al2O3） catalyst precursors were subjected to a second heat treatment at 500℃ or 700℃. The catalysts were characterized by N2 adsorption, H2-TPR, XRD and SEM, and their methanation performances were tested at 550℃, 3MPa, 5000h-1, and n （H2）/n （CO）=1.0 in the syngas containing H2S. The results indicated that the surface area of the catalyst was mainly affected by the calcination temperature of CeO2-Al2O3 support. While the dispersion of Co and Mo species were largely determined by the heat treatment temperature of catalyst precursor. The catalyst with the CeO2-Al2O3 support caicinated at 500℃ and the catalyst precursor treated at 700℃ showed the highest Co and Mo dispersion and the highest activity in methanation reaction.