Support-Accelerated Proton Transfer for Enhanced Oxygen Evolution Catalysis

Catalyst supports are conventionally regarded as inert substrates for dispersing and stabilizing active species. Here we show that supports can be deliberately engineered to actively participate in catalytic reactions by accelerating interfacial proton transfer in oxygen evolution reaction (OER). IrO₂ clusters were supported on hydroxyl- and methyl-functionalized zirconium phosphate, yielding IrO₂/OH-ZrP and IrO₂/CH₃-ZrP, respectively. In-situ spectroscopy, electrochemical measurements and theoretical calculations reveal that, different from IrO₂/CH₃-ZrP, which follows the conventional adsorbate evolution mechanism (AEM), the -OH groups in IrO₂/OH-ZrP directly participate in OER by lowering *OOH deprotonation barrier and significantly facilitating proton transfer, leading to a Support-Accelerated Proton Transfer AEM (SAEM). Notably, rotation-dependent OER activity studies coupled with local pH measurements provide direct and compelling evidence of the support-mediated proton transfer process. Consequently, IrO₂/OH-ZrP achieves a turnover frequency of 3.35 s^-1 at an overpotential of 300 mV, 2.99 times higher than that of IrO₂/CH₃-ZrP. This study underscores the significance of support engineering in proton-transfer limiting reactions and provides new insights into electrocatalyst design beyond active site engineering.