Modulating hydrogen bonding in single-atom catalysts to break scaling relation for oxygen evolution

The universal scaling relation between reaction intermediates with correlated adsorption has restricted energy-conversion efficiency in some catalytic processes such as oxygen evolution reaction (OER) for hydrogen production. Overcoming this intrinsic barrier requires differentiated adsorption of oxygenated intermediates. In this work, we introduce single-atom Ir species on CoOOH and Co0.8Cu0.2OOH, where their hydrogen bonding interactions with *OH and *OOH intermediates were tuned by localized structures. Electrochemical methanol oxidation measurements and in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra revealed different adsorptions of *OH and *OOH intermediates over Ir-1/CoOOH and Ir-1/Co0.8Cu0.2OOH. Theoretical calculations further showed that the presence of cationic vacancies in Ir-1/Co0.8Cu0.2OOH elongates the interaction distance between atomic iridium species and one of the key intermediates, *OH, leading to distinct adsorptions of *OH and *OOH. Consequently, Ir-1/Co-0.8 Cu0.2OOH overcome the theoretical minimum energy barrier of 370mV towardOER under scaling relation, presenting a lower theoretical overpotential barrier of 310 mV.