Efficient Charge Transfer and Bubble Traffic in Nanosheet/Nanowire Catalysts Enable High-Rate Alkaline Hydrogen Evolution

Alkaline water electrolysis (AWE) shows great potential for sustainable hydrogen production, but its deployment is hindered by insufficient charge/mass transfer at electrode–electrolyte interfaces. Herein, we report a distinctive heterostructure featuring NiOOH nanosheets with Ru doping immobilized on NiMoSx (RuNiOOH/NiMoSx) to address this challenge. Theoretical predictions and experimental results demonstrate that the charge redistribution in the RuNiOOH/NiMoSx heterostructure downshifts the Ru d-band center, thereby optimizing H* binding strength and the unique heterostructure provides a multitude of accessible active sites and three-dimensional (3D) mass transport channels, synergistically facilitating H2O adsorption and bubble desorption. Such optimized bubble dynamics ensure rapid active-site regeneration and sustained catalytic activity. As a consequence, the RuNiOOH/NiMoSx electrode exhibits outstanding hydrogen evolution reaction (HER) performance, delivering current densities of 10 and 500 mA cm–2 at overpotentials of 5.4 and 136.2 mV, respectively, while maintaining outstanding stability over 100 h at 100 mA cm–2. Furthermore, RuNiOOH/NiMoSx-based practical alkaline water electrolyzer drives 1.0 A cm–2 at a cell voltage of just 1.75 V for over 24 h without degradation. The present research delivers a new design paradigm for advanced heterostructured catalysts.