Theoretical investigation on electrocatalytic reduction of CO2 to methanol and methane by bimetallic atoms TM1/TM2-N@Gra (TM = Fe, Co, Ni, Cu)

Abstract

Atom-dispersed catalysts such as single atom catalysts (SACs) and dual atom catalysts (DACs) can improve the atomic utilization and catalytic activity obviously in electrocatalytic CO2 reduction reaction (CO2RR). However, the current trial and error synthesis method of the catalysts is still the main experimental strategy, which consumes a lot of time and energy. Hence, we employed density functional theory (DFT) to design ten different transition metal DACs to compare and analyze the impact of electronic structures on their catalytic properties. Due to two metal atoms in DACs for adsorbing intermediates at the bridge site, it provides an unusual pathway for CO2RR to multi-electron reduction products, which helps formic acid to be further reduced as an intermediate rather than desorbed as a product. Among them, Fe/Co-N@Gra and Co2-N@Gra display better catalytic performance and product selectivity for methane with a low limiting potential (−0.37 V). This work investigates the CO2RR catalytic performance of inexpensive metal in atomic-level insights, which would be helpful for synthesizing catalysts efficiently with fewer experimental attempts.