Engineering the interfacial water hydrogen-bond network for enhanced alkaline hydrogen evolution

The alkaline hydrogen evolution reaction (HER) plays a crucial role in advancing sustainable hydrogen production technologies. However, the limited abundance and reactivity of interfacial water molecules significantly hinder the reaction kinetics. This research develops a WC_x-supported PtNi alloy (PtNi/WC_x) catalyst to reorganize the hydrogen-bond arrangement of interfacial water by adjusting electron density at metal sites. In situ Raman coupled with ab initio molecular dynamics (AIMD) is employed to investigate how the interfacial hydrogen-bond network influences catalytic activity. These results demonstrate that the electron-rich Pt sites in PtNi/WC_x disrupt the hydrogen-bond network by altering the alignment of water molecules. This disruption enhances the mobility and reactivity of H₂O* and OH* intermediates at the solid-liquid interface. The optimized PtNi/WC_x catalyst achieves exceptional HER activity, requiring only 16 mV at 10 mA cm⁻² and 78 mV at 100 mA cm⁻². These findings offer a microscopic perspective and theoretical guidelines for optimizing HER catalysts via interfacial water structure manipulation.