Ni based catalyst supported on KIT-6 silica for CO methanation: Confinement effect of three dimensional channel on NiO and Ni particles

Abstract

Several nickel catalysts supported on silica KIT-6 were synthesized via the incipient wetness impregnation method and the performance of the catalysts in CO methanation were investigated in a continuous flow fixed bed reactor. The mesoporous silica KIT-6 has three dimensional framework and large surface area, which can offer adequate sites for the metal to disperse. The amount of nickel loading has significantly affected the metal surface area and dispersion of nickel particles on the support. The catalysts with higher Ni loading exhibited better activity in CO methanation. It was also found that, compared with Al2O3, SiO2 and even meseporous SBA-15, KIT-6 silica has an obvious confinement effect to NiO particles as the size of NiO particles maintained consistent under different calcination temperature. However, at higher temperature, metallic nickel particles sintered due to the Ostwald ripening effect, which caused the pore blocking of the support and further led to the deactivation of the catalysts.