The difference of roles of alkaline-earth metal oxides on silica-supported nickel catalysts for CO2 methanation

Abstract

The roles of alkaline-earth metal oxides on CO₂ methanation over modified Ni/SiO₂ catalysts were investigated. Ni/MO/SiO₂ catalysts with variable elements (M = Mg, Ca, Sr and Ba) were prepared by the sequential impregnation method. The results indicated that the presence of SrO promoted the catalytic activity and enhanced the catalyst stability. In addition, BaO addition enhanced the reaction activity, but the Ni/BaO/SiO₂ catalyst deactivated significantly after 50 h of time-on-stream due to the sintering of metallic Ni. Moreover, CaO addition affected negligibly the performance of the Ni/CaO/SiO₂ catalyst, and MgO addition inhibited significantly the methanation performance because of the low reducibility of Ni species.