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.