Recent progress of 3d transition metal single-atom catalysts for electrochemical CO(2) reduction

Recent studies have shown that single-atom catalysts (SACs) have significantly better catalytic activity and selectivity for the electrochemical CO₂ reduction reaction (CRR) compared to their bulk metal and nanostructured counterparts. However, there are few relevant articles reviewing SACs for the CRR, despite their importance in the field. Herein, the scope of this review is the recent development of single-atom 3d-block transition metal catalysts (metal = Mn, Fe, Co, Ni, Cu, Zn) and their application as electrocatalysts for the CRR. The recent representative works by metal are summarized. Results show that 1) Ni and Fe SACs exhibit superior catalytic performance for CO evolution; 2) Co, Mn, Zn SACs are less reported due to their relative inertness for the CRR; 3) Cu SACs have ordinary catalytic activity for the CRR, however, C2 products are observed in a few reports. Point (3) is attractive to the prospective study of CO₂ to highly reduced products. Finally, some suggestions for the future development of SACs for the CRR are briefly proposed.Chaochen Xu, Anthony Vasileff, Yao Zheng, and Shi-Zhang Qia