Mechanistic Elucidation of the Hydrogen Evolution Reaction on Ni–Mo Alloys via Surface and Data-Driven Kinetic Analyses

Understanding the active sites and mechanisms of the hydrogen evolution reaction (HER) is essential for the design of efficient water-electrolysis catalysts. Herein, we synthesized Ni–Mo alloy electrodes with varying Mo compositions and systematically examined their HER performance under alkaline conditions. Electrochemical and surface analyses (SEM, XPS, EIS) revealed that HER activity is closely related to Mo content and evolved upon potential cycling due to surface restructuring, including Mo dissolutions. Furthermore, a genetic algorithm-based kinetic analysis was employed to estimate rate constants and deviations in hydrogen binding energy (Δ G H ) from thermoneutrality, enabling the identification of composition-dependent HER pathways. This study highlights the potential of integrating data-driven kinetic modeling with surface characterization to provide mechanistic insights and design principles for HER electrocatalysts.