Computational screening aided design of single atom-doped MoS2 as electrocatalysts in nitrogen fixation

Abstract

Nitrogenase's structure has catalyzed the evolution of bio-inspired catalysts, specifically transition metal sulfides, echoing the enzyme's cofactor architecture. Molybdenum-based derivatives, mirroring nitrogenase's active sites, demonstrate potential in electrochemical nitrogen reduction for ambient ammonia synthesis. However, achieving an optimal balance between nitrogen activation and hydrogen production presents a significant hurdle. To address this, we utilized MoS₂, structurally akin to natural nitrogenase, decorated with doped transition single atoms to enhance catalytic performance. Employing accelerated high-throughput density functional theory (DFT) calculations, W-doped MoS₂ with sulfur vacancies (Sv-W-MoS₂) was identified as a leading candidate, showcasing improved selectivity for N₂ activation while maintaining a hydrogen production profile akin to nitrogenase's NH₃ synthesis, often accompanied by a proportionate amount of H₂. Experimental validation confirmed the superior NH₃ generation capacity of Sv-W-MoS₂, achieving a substantial yield of 62.42 μg h⁻¹ cm⁻² with a faradaic efficiency of 22.34% under alkaline conditions at −0.5 V versus the reversible hydrogen electrode (vs. RHE), outshining other metal-doped MoS₂ variants. This breakthrough offers a solid theoretical framework for the development of bio-inspired nitrogen reduction reaction (NRR) catalysts, aiming to harmonize nitrogen activation with hydrogen production.