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.