Synergistic M‐O Dual‐Atom Pairs Induced Interfacial Water Hydrogen Bonding Network for Boosting MoSe₂ Electrocatalytic Performance

Abstract Understanding the dynamics changes of the water network at the electrode–solution interface during the hydrogen evolution reaction (HER) process, including how it is doubly regulated by the electrode material and electrolyte pH, and its subsequent effects on the reaction intermediates (H^* and OH^*), is crucial in electrochemistry. However, relevant studies are limited due to water's its dual role as both a reactant and a solvent. Thus, it is essential to construct an ideal model capable of decoupling the effects of interfacial water action from the surface catalytic HER process. In this study, M‐O atom pairs doped MoSe₂ model catalyst is developed to achieve this goal and tailor the water network structure in a double‐layer microenvironment. Combined with molecular dynamics simulations and in situ spectroscopic characterization, correlations between water configuration, the water network, and water dissociation with HER activity are successfully established. This findings reveal that the pH‐dependent hydrogen‐bonding environment, modulated by oxophilic species, exerts a greater influence on acidic HER compared to alkaline media. The optimized Rh,O‐MoSe_2‐x catalyst demonstrates exceptional performance in both acid and alkaline electrolytes and shows no activity decay during a PEMWE test at 1.5 A cm⁻², making it promising for scalable water electrolyzers.