Preparation of Ce-modified Raney Ni Catalysts and Their Application in Aqueous-Phase Reforming of Cellulose

摘要

Abstract A series of Ce-modified Raney Ni (RNi) catalysts were successfully prepared by a simple wet chemical route and employed in aqueous-phase reforming of cellulose. Remarkable enhancement in hydrogen selectivity and yield after the Ce introduction was observed. At 533 K and autogenous pressure, a highest hydrogen yield of 17.8 mmol/g_cellulose, which was comparable with that of 5 wt% Pt/AC, could be obtained over Ce-modified catalyst at a Ce:Ni ratio of 0.054. The catalysts were characterized by N₂ adsorption/desorption, XRD, SEM, XPS and H₂-TPD. It was found that cerium existed at the surface of the catalyst as Ce(OH)₃, and more defects were generated during Ce modification. Based on the characterization and catalytic performance, it was suggested that the deposited Ce(OH)₃ may transform into reducible CeO₂ under the reaction conditions, thus promoting the desired water–gas shift reaction, leading to more H₂. On the other hand, the active sites for undesired methanation reaction may be effectively poisoned by Ce modification, thus leading to less undesired methane.