Recent progress of theoretical studies on electro- and photo-chemical conversion of CO 2 with single-atom catalysts.

The CO 2 reduction reaction (CO 2 RR) into chemical products is a promising and efficient way to combat the global warming issue and greenhouse effect. The viability of the CO 2 RR critically rests with finding highly active and selective catalysts that can accomplish the desired chemical transformation. Single-atom catalysts (SACs) are ideal in fulfilling this goal due to the well-defined active sites and support-tunable electronic structure, and exhibit enhanced activity and high selectivity for the CO 2 RR. In this review, we present the recent progress of quantum-theoretical studies on electro- and photo-chemical conversion of CO 2 with SACs and frameworks. Various calculated products of CO 2 RR with SACs have been discussed, including CO, acids, alcohols, hydrocarbons and other organics. Meanwhile, the critical challenges and the pathway towards improving the efficiency of the CO 2 RR have also been discussed.