The electrochemical CO2 reduction reaction on TM–C3N5 for C1 products: a DFT study

Abstract

In the electrochemical CO₂ reduction reaction (CO₂RR), transition metal atoms embedded in carbon and nitrogen materials are widely used as highly efficient catalysts because of their excellent catalytic activity and maximum atomic utilization. In this study, we used density functional theory (DFT) to screen catalysts with both thermodynamic and electrochemical stability of Fe–C₃N₅, Co–C₃N₅, Ni–C₃N₅ and Cu–C₃N₅ from 3d transition metal atoms embedded in C₃N₅ (TM–C₃N₅, TM = Sc–Zn). The adsorption and activation of CO₂ on the four catalysts were analyzed by means of Bader charge and projected density of states (PDOS). The ultimate potential (U_L) and crystal orbital Hamilton population (COHP) analysis showed that the dominant product of CO₂ on Fe–C₃N₅ and Ni–C₃N₅ was HCOOH, with excellent activity and selectivity. Cu–C₃N₅ has good ability to reduce CO₂ to CH₃OH. At the same time, Fe–C₃N₅, Ni–C₃N₅ and Cu–C₃N₅ can effectively inhibit the occurrence of the HER.