Highly-selective Electrocatalytic Reduction of NO to NH using Cu Embedded WS Monolayer as Single-atom Catalyst: A DFT Study.

Electrocatalytic nitric oxide reduction reaction (NORR) is a promising method for generating NH and eliminating harmful NO pollutants. However, developing a NORR catalyst for NH synthesis with low cost and high efficiency is still challenging. We here report a series of single-atom catalysts (SACs), designed by embedding nine different transition metals from Sc to Cu in S-vacant WS monolayer (TM@WS), and investigate the electrocatalytic performance for NORR process using the dispersion-corrected density functional theory (DFT) calculations. Among the nine SACs, Cu-based one shows a strong binding to the WS surface and high selectivity for the NORR process, and also it greatly inhibits the competing hydrogen evolution reaction (HER). Through ab initio molecular dynamics (AIMD) simulations, the thermal stability of SAC is assessed and found no structure deformation even at 500 K temperature. With the advent of energy descriptor, all possible reactive pathways including distal and alternating mode at both N- and O-end configurations for NH production were explored. We predicted that the Cu@WS SAC exhibits remarkable catalytic activity and selectivity with lowest limiting potential of-0.41 V via the N-alternating pathway. Our study emphasize that the transition metal dichalcogenide (TMDC) based SACs are potential candidates for converting NO to NH, and this opens a new avenue in designing NORR catalysts with high catalytic performance.