Study on the catalytic performance of theoretical design series single-atom transition metal-doped TM-N3S-PC catalysts for electrochemical synthesis of NH3.

CONTEXT: Electrocatalytic nitrogen reduction to ammonia is a sustainable alternative to the energy-intensive Haber-Bosch process. Herein, density functional theory calculations were used to systematically evaluate the N2 reduction reaction over 23 TM-N3S-PC catalysts, assessing adsorption configurations, energies, and charge transfer. Based on free energy changes of the first and last protonation steps and the competing H adsorption, five active catalysts (V, Cr, Mn, W, Nb) were selected. Detailed mechanism analyses reveal that V and Nb favor the Consecutive pathway, while Cr, Mn, and W proceed via the Distal pathway. Cr-N3S-PC exhibits the highest limiting potential. The Nb‑N₃S‑PC and W‑N₃S‑PC catalysts hold potential for ENRR and can outcompete the HER. This work provides theoretical insights for the rational design of N2 to NH3 electrocatalysts.

METHODS

The configuration, adsorption energy and charge transfer were investigated using the VASP software. The PBE generalized gradient approximation was employed, and the Grimme's DFT-D3 method was applied in all calculations to incorporate van der Waals corrections. AIMD simulations based on the NVT ensemble were performed to predict the stability of the catalysts. AIMD simulations were conducted using the CP2K 2.3.1 package.