Recent advances in catalytic systems for CO₂ conversion to substitute natural gas (SNG): Perspective and challenges

It has been well established that carbon dioxide (CO₂) is one of the main greenhouse gasses and a leading driver of climate change. The chemical conversion of CO₂ to substitute natural gas (SNG) in the presence of renewable hydrogen is one of the most promising solutions by a well-known process called CO₂ methanation. There have been comprehensive efforts in developing effective and efficient CO₂ methanation catalytic systems. However, the choice of competitive and stable catalysts is still a monumental obstruction and a great challenge towards the commercialization and industrialization of CO₂ methanation. It is necessary to emphasize the critical understandings of intrinsic and extrinsic interactions of catalyst components (active metal, support, promoter, etc.) for enhanced catalytic performance and stability during CO₂ methanation. This study reviews the up-to-date developments on CO₂ methanation catalysts and the optimal synergistic relationship between active metals, support, and promoters during the catalytic activity. The existing catalysts and their novel properties for enhanced CO₂ methanation were elucidated using the state-of-the-art experimental and theoretical techniques. The selection of an appropriate synthesis method, catalytic activity for CO₂ methanation, deactivation of the catalysts, and reaction mechanisms studies, have been explicitly compared and explained. Therefore, future efforts should be directed towards the sustainable developments of catalytic configurations for successful industrial applications of CO₂ utilization to SNG using CO₂ methanation.