Theoretical study of single transition metal atom catalysts supported on two-dimensional Nb2NO2 for efficient electrochemical CO2 reduction to CH4

Abstract

The design of highly efficient catalysts for electrochemical reduction CO2 (ECR) to value-add chemicals and fuels is important for CO2 conversion technologies. In this work, earth abundant transition metal (TM = V, Cr, Mn, Fe, Co and Ni) atoms embedded into two-dimensional (2D) Nb2NO2 (TM@Nb2NO2) as single-atom catalysts (SACs) for ECR was investigated by first-principles study. We demonstrated that Nb2NO2 can be an excellent substrate for anchoring single TM atom due to its excellent stability and electronic conductivity. Besides, V, Cr and Ni@Nb2NO2 could effectively promote CO2 adsorption and reduction. All TM@Nb2NO2 exhibit high selectivity towards CH4, and V, Cr and Ni@Nb2NO2 show low limiting potentials. The activity origin was revealed by analysing adsorption energy, d band centre, bonding/antibonding population and the change of valence state of TM atoms.