Impact of Nickel Phosphides Over Ni/SiO2 Catalysts in Dry Methane Reforming

A series of relative inert SiO2 supported NiP-x/SiO2 catalysts, containing different ratio of metallic nickel to nickel phosphides, were employed to clarify the synergistic effect of metallic nickel-nickel phosphides in dry methane reforming reaction. Ni/SiO2 catalyst exhibits good activity but severe carbon deposition and visible nickel particles sintering in dry methane reforming, which results in evident deactivation after 50 h reaction. The presence of P increases the dispersion of nickel species, results in smaller nickel species particles size. The co-existence of metallic nickel and nickel phosphides species was confirmed by multiple characterizations. Because of the relative stronger CO2 dissociation properties, NiP-x/SiO2 catalysts exhibit higher resistance of carbon deposition. In addition, P content makes great difference to not only carbon deposition but also activity in dry methane reforming. NiP-3/SiO2, which has good activity, stability and anti-coking properties in dry methane reforming, is the optimal catalyst in our study scope. [GRAPHICS] .