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

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/gcellulose, 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. Addition of Ce to Raney Ni catalysts could significantly enhance the hydrogen selectivity and yield for aqueous-phase reforming of cellulose, while correspondingly suppressing the methanation reaction. A highest hydrogen yield of 17.8 mmol/gcellulose, which was comparable with that of 5 wt% Pt/AC, could be obtained at a Ce:Ni ratio of 0.054.