Theoretical Screening of Single Transition Metal Atoms Embedded in MXene Defects as Superior Electrocatalyst of Nitrogen Reduction Reaction

Abstract The MXene‐supported single transition metal systems have been reported as promising electrocatalysts for hydrogen evolution reaction (HER) and carbon dioxide reduction reaction. Herein, the potential performance of MXene‐based catalysts was explored on nitrogen reduction reaction (NRR). Density functional theory computations are carried out to screen a series of transition metal atoms confined in a vacancy of MXene nanosheet (Mo 2 TiC 2 O 2 ). The results reveal that the Zr, Mo, Hf, Ta, W, Re, and Os supported on defective Mo 2 TiC 2 O 2 layer can significantly promote the NRR process. Among them, Zr‐doped single atom catalyst (Mo 2 TiC 2 O 2 ‐Zr SA ) possesses the lowest barrier (0.15 eV) of the potential‐determining step, as well as high selectivity over HER competition. To the best of knowledge, 0.15 eV is the lowest barrier of potential‐determining step that has been reported for NRR so far. Besides, the formation energy of Mo 2 TiC 2 O 2 ‐Zr SA is much more negative than that of the synthesized Mo 2 TiC 2 O 2 ‐Pt SA catalyst, suggesting that the experimental preparation of Mo 2 TiC 2 O 2 ‐Zr SA is feasible. This work thus predicts an efficient electrocatalyst for the reduction of N 2 to NH 3 at ambient conditions.