The synergistic effect of Ir and oxygen vacancies on Enhancing the OER performance of Surface-Reconstructed FeCo LDH

Abstract

The modification of Ir or oxygen vacancies (Vo) is a strategy to enhance the oxygen evolution reaction (OER) performance of heterogeneous nanocatalysts. However, it is crucial to further clarify the synergistic effect of Ir and Vo on the enhancement mechanism of OER performance after surface reconstruction. In this work, FeCo Layered double hydroxides (LDHs) co-modified by Ir and Vo were successfully prepared by the thermodynamically favorable galvanic replacement reaction. Electrochemical impedance spectroscopy confirmed that the synergistic effect of Ir and Vo enhanced the charge transfer of FeCo LDHs. XPS spectra reveal robust interactions between Ir and FeCo LDHs. Density-functional theory further reveals that the low-oxygen-coordinated Ir (III) acts as an active site to optimize the OER rate-determining step energy barrier. As a result, Ir and Vo co-modified FeCo LDH requires only a 203 mV overpotential to achieve a current density of 10 mA cm−2 and, more importantly, operates stably at an industrial current density of 250 mA cm−2 for 312 h without degradation. This work provides new insights and avenues for understanding the enhanced performance mechanism of catalysts after surface reconstruction and for industrial scale-up production.