Lewis Acid-Mediated\nInterfacial Water Supply for Sustainable\nProton Exchange Membrane Water Electrolysis

The catalyst–electrolyte interface\nplays a crucial\nrole\nin proton exchange membrane water electrolysis (PEMWE). However, optimizing\nthe interfacial hydrogen bonding to enhance both catalytic activity\nand stability remains a significant challenge. Here, a novel catalyst\ndesign strategy is proposed based on the hard–soft acid–base\nprinciple, employing hard Lewis acids (LAs = ZrO<sub>2</sub>, TiO<sub>2</sub>, HfO<sub>2</sub>) to mediate the reconfiguration of interfacial\nhydrogen bonding, thereby enhancing the acidic oxygen evolution reaction\n(OER) performance of RuO<sub>2</sub>. Mechanistic analysis indicates\nthat LAs prompt a directional evolution from a rigid hydrogen bonding\nnetwork to free water, enhancing the trapping of interfacial water\non the RuO<sub>2</sub> surface, which continuously supplies reactants\nto the catalytic sites. Moreover, the interconnected hydrogen bonding\nnetwork facilitates rapid proton transfer, reducing local acidity\non the catalyst surface and preventing structural corrosion, thus\nsignificantly improving long-term stability. The tandem pathway of\nwater supply and deprotonation transforms the dissolution mechanism\nof traditional Ru-based catalysts, emphasizing the widespread applicability.\nConsequently, ZrO<sub>2</sub>–RuO<sub>2</sub> displays a significantly\nreduced overpotential of 170 mV and exhibits high durability, sustaining\n1800 h at 10 mA cm<sup>–2</sup> under acidic OER, and maintains\nrobust activity for 100 h at 2 A cm<sup>–2</sup> in PEMWE,\noutperforming most Ru/Ir-based catalysts.