钴掺杂对碳化钼催化噻吩加氢脱硫性能的影响

以MoO3和CoMo混合氧化物为前驱体, 制备了碳化钼和碳化钼-钴催化剂, 采用XRD, BET, SEM和XPS等技术对其进行了表征, 研究了Co掺杂对碳化钼催化剂噻吩加氢脱硫性能的影响. 结果表明, 掺入适量的Co后制得的CoMo双金属混合氧化物为MoO3和CoMoO4的两相混合体, 经CH4/H2气氛程序升温还原碳化反应生成共生共存的Co-Mo2C, Co以金属细颗粒的形态均匀地分散在生成的Mo2C组分之间. 在共生过程中含Co物种的掺入可降低制备碳化钼所需要的还原碳化温度, 使制备的碳化钼颗粒变小, 比表面积增大, 表面Mo2+含量增多, 从而对碳化钼的噻吩加氢脱硫活性有较好的促进作用, Co的添加量以Co/Mo摩尔比为0.2左右较为适宜. 用化学共沉淀法制得的Co-Mo2C共生共存体系的噻吩加氢脱硫反应活性, 好于由金属Co与Mo2C机械混合法制得的Co+Mo2C二相共存体系. 这表明当两个活性相共存时, 只有经过相互共生过程才能发挥其最佳的协同效应.

Effect of Co Doping on the Cartalytic Performace of Molybdenum Carbide for Thiophene Hydrodesulfurization

Molybdenum carbide and cobalt molybdenum carbide catalysts,prepared by temperature-programmed reaction(TPR) with CH4/H2 gas mixture to carburize molybdenum trioxide and cobalt molybdenum oxide,were characterized via XRD,BET,SEM and XPS techniques.The effect of cobalt doping on the catalytic performance of molybdenum carbide for thiophene hydrodesulfurization(HDS) was studied.The results indicate that the cobalt molybdenum oxide is the compound oxide of MoO3 and CoMoO4,which produces a intergrowth and coexisting product of Co and Mo2C in the TPR carburization.Co dispersed uniformly in the component of Mo2C in the form of fine metallic particles.Co doping could decrease the carburizing temperature and particle size in the preparation process,increase the BET specific surface area and raise the content of Mo2 on the surface of molybdenum carbide catalyst.The thiophene HDS activity of Mo2C was obviously improved in the presence of Co doped by co-precipitation method with Mo,and the maximum synergistic interaction between Co and Mo appears at the Co/Mo molar ratio of 0.2.