A review of recent catalyst advances in CO2 methanation processes

This review focuses on various catalytic CO2 hydrogenation approaches for converting CO2 to fuels such as CH4. The catalytic CO2 methanation using thermal, catalytic-membrane, photo and plasma energy assisted processes were covered. The recent catalysts developments in thermo-catalytic systems for CO2 methanation in thermal process with respect to the nature of active catalytic centres and their performance were presented. Followed by the technological development of catalytic-membrane process and its advantages in overcoming thermodynamic equilibrium activities were also discussed. Additionally, the catalytic CO2 hydrogenation process assisted with plasma and photo energy were also covered with respect to the catalyst structures, CO2 conversion and selectivity towards various products. Several highly emerging in situ characterization techniques such as operando XAS and DRIFTS were used to understand the state of catalyst surface and reaction intermediates involved in CO2 methanation reaction. Furthermore, parameters affecting the selectivity towards desired products and methods to improve the performance are explained in greater details. Finally, a section for technological challenges of CO2 methanation in various processes are summarized and an outlook for future directions of the development of catalysts was provided to overcome the CO2 conversion and selectivity towards desired products limitations to eradicate the problems associated with global warming.