Boosting Efficient Water Oxidation via Photothermal‐Enhanced High‐Entropy Oxides With Dual AEM and LOM Pathways

ABSTRACT High‐entropy oxides (HEOs) with photothermal conversion capability provide a promising platform for enhancing the oxygen evolution reaction (OER) in electrocatalytic water splitting. In this work, the adsorbate evolution mechanism (AEM), the lattice oxygen mechanism (LOM), and photothermal effects are integrated into a single reaction system through Fe doping into HEOs. By combining theoretical calculations and experimental characterizations, we reveal that Fe doping optimally tailors the adsorption/desorption energetics of intermediates along the AEM, while simultaneously introducing oxygen vacancies that modulate the metal‐oxygen electronic environment and promote LOM participation. This dual‐pathway activation, enabled by the high‐entropy rock‐salt structure, enhances catalytic activity. In addition, the photothermal effect of (FeMgCoNiCuZn)O 1−x can accelerate interfacial charge‐transfer kinetics and facilitate OOH * deprotonation. Under Xe‐lamp irradiation, Fe doping lowers the apparent activation energy for OER from 15.3 to 11.2 kJ mol −1 , and the catalyst achieves oxygen evolution current densities of 10 and 50 mA cm −2 at overpotentials of 159 and 247 mV. More importantly, it exhibits outstanding long‐term durability, maintaining stable operation for over 1500 h at 1 A cm −2 . These findings underscore the potential of Fe‐doping hexanary HEOs as a highly efficient candidate for electrocatalytic water splitting.