• Edge-functionalization of MoS2 with transition metals, particularly W-substitution, significantly enhances nitrogen reduction reaction (NRR) activity, achieving a limiting potential below 0.20 V.
• Basal-adsorption and basal-substitution strategies are less effective due to electrochemical instability and poor NRR efficiency, respectively.
• Density functional theory (DFT) calculations reveal that the distal pathway is energetically favored for N2-to-NH3 conversion on the edge-functionalized MoS2.
• The findings provide a rational design strategy for high-performance MoS2-based electrocatalysts for green ammonia synthesis, offering guidance for experimental validation.