NO Electroreduction by Transition Metal Dichalcogenides with Chalcogen Vacancies

Nitric oxide electroreduction reaction (NOER) is one of the most attractive routes for ammonia synthesis and NO_x-related pollutant treatment. However, current research on NOER catalysts mainly focus on noble metals and single atom catalysts, while low-cost transition metal dichalcogenides (TMDs) are rarely considered, let alone their product selectivity. Herein, using first-principles calculations, we systematically investigate the performance of a series of single-layer TMDs (MoS₂, MoSe₂, MoTe₂, TaTe₂ and WTe₂) in the 1T’ phase as electrocatalysts for NOER. Our results reveal that defective 1T’-MoS₂ and 1T’-MoSe₂ monolayers (with the most common sulphur and selenium vacancies, respectively) exhibit excellent activity for NOER as well as high selectivity for ammonia, which can be correspondingly yielded at 0 and −0.06 V potentials, comparable to the best Pt-based and single atom catalysts. Furthermore, these two catalysts efficiently suppress the competing hydrogen evolution reaction (HER). Thus, single-layer TMDs synthesized with chalcogen vacancies may serve as efficient catalysts for electrochemical ammonia synthesis from pollutants and electrocatalytic denitrification.