Theoretical study on one-dimensional carbon nitride doped with transition metal for highly efficient and selective nitrogen reduction reaction

The inert nature of N₂ poses a significant challenge to the nitrogen reduction reaction (NRR). In this study, we theoretically investigated one-dimensional (1D) carbon nitride nanowire (1D-C₆N₇) structures doped with various transition metals (TM) as potential NRR catalysts. Employing density functional theory (DFT) calculations, we elucidated the regulation of bonding interactions between the d orbitals of transition metals and p orbitals of nitrogen via the “acceptance-donation” mechanism. This interaction results in the redistribution of electrons, shifting antibonding orbitals below the Fermi level and weakening the adsorption of N₂. Hence, adjusting the number of d electrons and the nature of orbital interactions can fine-tune the adsorption efficiency and NRR activity. Among the 11 transition metals studied, TM@1D-C₆N₇ (TM = Zr, Nb, Mo) exhibit significant potential for light-induced conversion of N₂ to NH₃ and demonstrate efficient absorption in the visible spectrum, indicating their potential as effective photocatalysts for NRR. Moreover, the analysis of adsorption free energies reveals the successful suppression of the competitive hydrogen evolution reaction (HER), highlighting the outstanding selectivity for NRR. By using ab initio molecular dynamics (AIMD) to verify structural stability, we identified Nb/Mo@1D-C₆N₇ as prime candidates for NRR owing to their high activity, selectivity, and stability.