Dynamic proton reservoir with hydrogen-bond-network-mediated proton transport pathway for efficient alkaline hydrogen...

The alkaline hydrogen evolution reaction (HER) is intrinsically limited by the lack of active hydrogen and sluggish hydrogen transfer. However, current strategies mainly optimize catalytic sites for water splitting or hydrogen adsorption, overlooking the demands of continuous hydrogen supply and rapid hydrogen transfer. Here, we report an IrO₂/WO₃ catalyst that enables dynamic engineering of proton reservoirs and transport pathways for accelerated alkaline HER. The catalyst exhibits exceptional alkaline HER activity, delivering an ultralow overpotential of 18 mV at 10 mA cm^-2 for alkaline HER. When integrated into a membrane-based alkaline electrolyzer, it achieves 1 A cm^-2 at only 1.68 V and retains stable performance for over 1000 h. Experimental and theoretical studies show that WO₃ undergoes reversible proton intercalation and deintercalation, acting as a dynamic proton reservoir. More importantly, the strong interfacial coupling between IrO₂ and WO₃ reconstructs an ordered hydrogen-bond network that serves as an efficient proton transport pathway and facilitates directional proton transfer to Ir active sites. Meanwhile, IrO₂ efficiently stabilizes H* intermediates, thereby accelerating H-H coupling. This work reveals the critical role of dynamic proton microenvironments in governing alkaline HER kinetics, providing a new strategy for proton-coupled electrocatalyst design.