Reaction Mechanisms and Applications of Single Atom Catalysts for Thermal-Catalytic Carbon Dioxide Hydrogenation Toward Oxygenates

Thermo-catalytic CO₂ hydrogenation to high-value oxygenates has been regarded as one of the most powerful strategies that can potentially alleviate excessive CO₂ emissions. However, due to the high chemical stability of CO₂ and the variability of hydrogenation pathways, it is still challenging to achieve highly active and selective CO₂ hydrogenation. Single atom catalysts (SACs) with ultrahigh metal utilization efficiency and extraordinary electronic features have displayed growing importance for thermo-catalytic CO₂ hydrogenation with multiple strategies developed to improve performances. Here, we review breakthroughs in developing SACs for efficient CO₂ hydrogenation toward common oxygenates (CO, HCOOH, CH₃OH, and CH₃CH₂OH) in the following order: first, an analysis of reaction mechanisms and thermodynamics challenges of CO₂ hydrogenation reactions; second, a summary of metal SAs designed by dividing them into the two categories of the single- and dual-sites; third, discussion of support effects with a focus on approaches to regulating strong metal–support interaction (MSI). Summarily, current challenges and future perspectives to develop higher-performance SACs in CO₂ hydrogenation are presented. We expect that this review can bring more design inspiration to trigger innovation in catalytic CO₂ evolution materials and eventually benefit the achievement of the carbon-neutrality goal.