Applied Surface Science, Vol.257, No.19, 8171-8176, 2011
The effect of heat treatment on the performance of the Ni/(Zr-Sm oxide) catalysts for carbon dioxide methanation
The active catalysts for methane formation from the gas mixture of CO2 + 4H(2) with almost 100% methane selectivity were prepared by reduction of the oxide mixture of NiO and ZrO2 prepared by calcination of aqueous ZrO2 sol with Sm(NO3)(3) and Ni(NO3)(2). The 50 at%Ni-50 at%(Zr-Sm oxide) catalyst consisting of 50 at%Ni-50 at%(Zr + Sm) with Zr/Sm = 5 calcined at 650 or 800 degrees C showed the highest activity for methanation. The active catalysts were Ni supported on tetragonal ZrO2, and the activity for methanation increased by an increase in inclusion of Sm3+ ions substituting Zr4+ ions in the tetragonal ZrO2 lattice as a result of an increase in calcination temperature. However, the increase in calcination temperature decreased BET surface area, metal dispersion and hydrogen uptake due to grain growth. Thus, the optimum calcination temperature existed. (C) 2011 Elsevier B. V. All rights reserved.
Keywords:CO2 methanation;Nearly 100% methane selectivity;Ni/tetragonal ZrO2 catalyst;Stabilization of tetragonal ZrO2;Oxygen vacancy