Remarkably stable and efficient Ni and Ni-Co catalysts for CO2 methanation

Abstract

• Efficient Ni and Ni-Co on alumina catalysts were prepared and characterized. • CO 2 methanation process is greener when using our Ni and Ni-Co catalysts. • The addition of cobalt improved the reducibility of nickel species. • The addition of cobalt improved activity and selectivity towards CH 4 . • Ni and Ni-Co catalysts showed high stability over 200 h of continuous reaction. CO 2 methanation is one of the most promising ways to store energy based on the power-to-gas concept. In this study, efficient nickel (Ni) and nickel-cobalt (Ni-Co), supported on alumina catalysts with different amounts of Ni and Co were prepared, characterized and used for CO 2 methanation under the atmospheric pressure. The catalysts were prepared in the form of extrudates for catalytic tests. The effect of Ni content and the influence of Co on Ni catalysts were studied in a packed bed methanation reactor at laboratory scale. An optimal Ni-Co content was identified based on CO 2 and H 2 conversion and CH 4 selectivity and yield. The addition of Co improved the reducibility of Ni species and Ni particles’ dispersion over the support. Therefore, the presence of Co enhanced the catalyst activity and selectivity towards CH 4 . Moreover, it was observed that low reaction temperatures (lower than 350 °C) can be used when lowering the Ni content (i.e. 10% wt.). This major fact is favourable to the reduction of the overall process energy consumption and to the decrease of the catalysts’ deactivation at high temperature (>400 °C), such as the active phase sintering. Finally, the Ni and Ni-Co catalysts prepared in this work for CO 2 methanation presented a remarkably high stability over 200 h of continuous reaction.