Highly-selective Electrocatalytic Reduction of NO to NH₃ using Cu Embedded WS₂ Monolayer as Single-atom Catalyst: A...

Electrocatalytic nitric oxide reduction reaction (NORR) is a promising method for generating NH₃ and eliminating harmful NO pollutants. However, developing a NORR catalyst for NH₃ 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 WS₂ monolayer (TM@WS₂), 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 WS₂ 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 NH₃ production were explored. We predicted that the Cu@WS₂ 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 NH₃, and this opens a new avenue in designing NORR catalysts with high catalytic performance.