Mechanistic Insights into Alkaline Electrosynthesis of Acetamide over Transition Metal-Doped MoS2: A Comprehensive DFT Investigation

Abstract

The electrosynthesis of acetamide in alkaline conditions via the coupling reduction of NO and CO₂ establishes a sustainable, efficient platform that enables simultaneous valorization of major atmospheric pollutant and primary greenhouse gas. However, limited catalytic activity and an unclear reaction mechanism in alkaline media remain critical challenges. Herein, in this study density functional theory (DFT) calculations systematically investigate a series of transition metal (TM) doped MoS₂ catalysts to elucidate the mechanism of acetamide electrosynthesis. Among the fourth-period TM dopants, Ni–MoS₂ exhibits the highest catalytic activity. Electronic structure analysis shows that Ni doping increases interfacial electron density and promotes surface reactivity. Ni–MoS₂ exhibits strong synergistic adsorption of NO (−0.44 eV) and CO₂ (−0.58 eV), accompanied by enhanced orbital hybridization and interfacial bonding interactions. Reaction pathway analysis reveals that Ni–MoS₂ facilitates the efficient formation of key intermediates (NH₂OH and CH₃CHO), shortens the overall reaction pathway, and suppresses competing side reactions, thereby improving both activity and selectivity. These intermediates subsequently undergo thermodynamically favorable C–N coupling on the Ni–MoS₂ surface, enabling efficient acetamide production with a limiting potential of −1.23 V. Overall, this work reveals a mechanistic relationship between the electronic properties of active sites, reaction energetics, and acetamide electrosynthesis performance, providing theoretical insights for the rational design of high-performance electrocatalysts.