Revealing the hydrogen bond network effect at the electrode–electrolyte interface during the hydrogen evolution reaction†

The hydrogen bond network (HBN) in the electrical double layer (EDL) at the electrode–electrolyte interface plays a crucial role in governing water migration, which directly affects the efficiency of the hydrogen evolution reaction. However, existing research has primarily focused on the connectivity of the HBN within the inner Helmholtz layer, often neglecting the water transport across the entire EDL. In this study, we develop a high-performance Aermet100 steel-derived catalyst, which achieves an overpotential of 307 mV for the hydrogen evolution reaction at a current density of 500 mA cm⁻² under industrial conditions. Using this catalyst, we investigate the migration of water in KOH solutions with varying concentrations. Our findings show that water migration is inhibited in 1 M KOH due to the relatively stronger HBN, whereas it is enhanced in 3 M and 6 M KOH solutions. These results provide new insights into the kinetics of water transport and offer a potential pathway for optimizing industrial water electrolysis processes.