Electron enrichment enables RuPd to achieve 1.406 V overall water splitting

The development of cost-effective and stable bifunctional catalysts is crucial for reducing the cost of green hydrogen production via water electrolysis. Herein, we report a RuPd-RuNiFeO _x catalyst supported on nickel foam, synthesized via a facile non-homogeneous nucleation method. The catalyst exhibits exceptional hydrogen evolution (HER, 17 mV@10 mA cm^-2) and oxygen evolution (OER, 263 mV@50 mA cm^-2) activities in alkaline freshwater, requiring only 1.406 V for overall water splitting at 10 mA cm^-2 with outstanding stability over 100 h. Remarkable performance is also demonstrated in seawater electrolysis. Combined experimental characterization and density functional theory (DFT) calculations reveal that the superior activity and stability originate from electron enrichment at the interfacial Ru sites, driven by charge redistribution from the NiFeO _x support to the RuPd cluster. This electron enrichment optimizes the d-band center of Ru, yielding a near-ideal hydrogen adsorption free energy (ΔG _H*≈ -0.10 eV), and significantly reduces energy barriers for both water dissociation and the OER rate-determining step. This work provides mechanistic understanding and a practical strategy for designing high-performance, durable catalysts for sustainable hydrogen production.