Localized electronic interaction dictates electrolysis reactivity of long-range palladium particles

Harnessing the charge transfer between metal and semiconductor supports can radically boost the catalytic activity of electrode material. At the microscopic level, relative to the single-atom catalyst systems and well-defined models, etc., the details of long-range metal particle-semiconductor interactions are remain obscure. This study, through surface oxygenation protocol, confirms two types of metal-support interaction on metal assays of technologically important Pd/C catalysts during the electrolysis of H₂O₂: electron transfer from the Pd particle to the carbon and localized electronic disturbance between Pd/PdO interfaces, thus is inherently an electronic metal-support interaction effect. Remarkably, detailed spectroscopic investigations and theory simulation reveal that interfacial positive palladium governs the reactivity of Pd/PdO in the electrolysis of H₂O₂. Regarding the electron redistribution on palladium particles (50-100 nm), metallic and positively charged Pd moieties enable bifunctional electrolysis. This finding details the quest for catalytically indispensable Pd-O species on carbon and clarifies the prevailing structure-activity relationships of Pd-based catalysts.