Dual transition metal atoms embedded in N-doped graphene for electrochemical nitrogen fixation under ambient conditions

Abstract

A systematic study on the catalytic performance of dual transition metal atoms (3d, 4d and 5d) embedded in three types of N-doped graphene (DV, TV, QV) for electrocatalytic nitrogen reduction reaction (NRR) was conducted by first-principles calculations, high-throughput screening and molecular dynamic simulations. Full reaction pathway search of the screened candidates shows Cr₂-TV, Mo₂-TV and Ir₂-TV to be the promising catalysts for NRR with onset potentials of −0.24, −0.39 and −0.38 V, respectively. In-deep analysis of the band structure, projected density of states, spin density, charge density difference, Bader charge population of N₂ molecule adsorbed on catalysts unveil that the charge transfer between the adsorbed N₂ molecules and the metal atoms in catalysts, good electronic conductivity, and significant orbital hybridization account for the high catalytic efficiency of NRR on Cr₂-TV, Mo₂-TV and Ir₂-TV. The evaluation of stability and selectivity of the three catalysts indicates that all three catalysts display high stabilities, and Cr₂-/Mo₂-TV shows good NRR selectivity compared to HER. Our present study sheds some insights on the design of novel dimetal anchored N-doped graphene as efficient electrocatalysts for NRR, promoting both experimental and theoretical investigations in this direction.