Abstract
A series of NiP-x/Al(2)O(3) catalysts containing different ratio of metallic nickel to nickel phosphides, prepared by varying Ni/P molar ratio of 4, 3, 2 through a co-impregnation method, were employed to investigate the synergistic effect of metallic nickel-nickel phosphides in dry methane reforming reaction. The Ni/Al(2)O(3) catalyst indicates good activity along with severe carbon deposition. The presence of phosphorus increases nickel dispersion as well as the interaction between nickel and alumina support, which results in smaller nickel particles. The co-existence of metallic nickel and nickel phosphides species is confirmed at all the P contained catalysts. Due to the relative stronger CO(2) dissociation ability, the NiP-x/Al(2)O(3) catalysts indicate obvious higher resistance of carbon deposition. Furthermore, because of good balance between CH(4) dissociation and CO(2) dissociation, NiP-2/Al(2)O(3) catalyst exhibits best resistance of carbon deposition, few carbon depositions were formed after 50 h of dry methane reforming.