CO2 electroreduction performance of a single transition metal atom supported on porphyrin-like graphene: a computational study

Searching for low-cost, efficient, and stable electrocatalysts for CO2 electroreduction (CO2ER) reactions is highly desirable for the reduction of CO2 emission and its conversion into useful products, but remains a great challenge. In this work, single transition metal atoms supported on porphyrin-like graphene catalysts, i.e., TMN4/graphene, acting as electrocatalysts for CO2 reduction were explored by means of comprehensive density functional theory (DFT) computations. Our results revealed that these anchored TM atoms possess high stability due to their strong hybridization with the unsaturated N atoms of the substrate and function as the active sites. On the basis of the calculated adsorption strength of CO2ER intermediates, we have identified that single Co, Rh, and Ir atoms exhibit superior catalytic activity towards CO2 reduction. In particular, CH3OH is the preferred product of CO2ER on the CoN4/graphene catalyst with an overpotential of 0.59 V, while the RhN4/graphene and IrN4/graphene catalysts prefer to reduce CO2 to CH2O with an overpotential of 0.35 and 0.29 V, respectively. Our work may open a new avenue for the development of catalytic materials with high efficiency for CO2 electroreduction.