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

A comparison of the dual atom catalysts composed of four common inexpensive metal shows that the two combinations of Fe/Co and Co2 exhibit low CH3OH limiting potential and superior CH4 selectivity, respectively. [Display omitted] •Stable *HCOOH intermediate provides an unusual pathway for CO2RR to CH3OH and CH4.•Fe/Co-N@Gra and exhibits extremely low limiting potential for CH3OH.•There is excellent CH4 selectivity for Co2-N@Gra under low applied potential.•The mechanism of dual-atom electronic regulation is improved at the atomic level. 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.