Cerium-promoted nickel catalysts supported on yttrium-doped γ-alumina for carbon dioxide methanation

Abstract

The catalytic performance of the Ni/Al, Y-doped Ni/Al-xY, and Ce-promoted Ni-yCe/Al-15Y catalysts for CO2 methanation was examined. The CO2 conversion and CH4 yield increased in the order of Ni/Al < Ni/Al-5Y < Ni/Al-25Y < Ni/Al-15Y at temperatures below 350 °C. The reduction degree, H2 uptake, and total CO2 adsorption uptake increased in this order for the Ni/Al-xY catalysts, suggesting that doping γ-Al2O3 with a moderate amount of Y improved the interaction between the nickel and the support. When the Ni/Al-15Y catalyst was promoted by Ce with different contents (0–5 wt%), the catalyst with 2 wt% Ce exhibited the highest CO2 conversion (92.5%) and CH4 yield (92.2%) at ≤ 350 °C. As evidenced by catalyst characterization, cerium promoter results in a synergetic Ni–Ce interaction over the combined Al-15Y support, leading to the formation of finely dispersed metal species and numerous active sites for splitting of the stable C–O bond.