A review of the indispensable role of oxygen vacancies for enhanced CO₂ methanation activity over CeO₂-based catalysts: Uncovering, influencing, and tuning strategies

It is generally accepted that carbon dioxide (CO₂) is one of the most important greenhouse gases and a primary factor in the acceleration of climate change. Methanation, which involves converting CO₂ to methane in the presence of renewable hydrogen, is a plausible technique for achieving net-zero atmospheric CO₂ concentrations. Nevertheless, the development of effective catalytic systems continues to be a significant barrier tor CO₂ methanation. CeO₂-based catalysts for CO₂ methanation could benefit from tuning their oxygen vacancies (OVs) to increase catalytic performance. This review examines and discusses in depth a number of different characterization methodologies for measuring OVs. Additionally, this review focuses specifically on the role that OVs play in various CeO₂-based catalysts as well as the numerous tuning strategies that may be used to increase the number of OVs in these catalysts. This study could give scientists new ideas for how to improve catalytic CO₂ methanation.