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

Abstract

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.