Preparation of highly active and stable NiO–CeO2 nanocatalysts for CO selective methanation

• CO methanation in hydrogen rich stream over Ni/CeO2 nanocatalysts.
• CeO2 within formation of oxygen vacancies can tune the catalytic performance.
• Synthesis of high surface area nanostructured catalyst.
• Catalytic methanation is a structure sensitive reaction.
• The 50%Ni/CeO2 catalyst shows excellent activity in CO selective methanation.

In the present work, a group of nickel-ceria nanocatalysts was synthesized by co-precipitation method and their catalytic performances were considered in CO methanation reaction. The catalysts were characterized by XRD, BET, SEM, TEM, H2-TPR, CO chemisorption and CO-TPD techniques. The results showed that addition of nickel content up to 50 wt.% increased both the CO conversion and CH4 selectivity at low temperatures while further increase in nickel content adversely affected them. The 50%Ni/CeO2 catalyst revealed an excellent activity in CO methanation due to high surface area (258 m2/g), small nickel particle size (below 5 nm) and high metal dispersion (7.31%). In CO selective methanation, CO2 conversion was completely suppressed until CO conversion reached to a maximum value, which is an important factor from commercial view point where is needed to extend operating temperature window between maximum of CO conversion and suppressing of CO2 methanation.