High-Entropy Effect Promoting Self-Healing Behavior of Two-Dimensional Metal Oxide Electrocatalysts for Oxygen Evolution Reaction

The irreversible leaching of metal atoms during the alkaline oxygen evolution reaction (OER) process greatly hinders the long-term stability of OER catalysts. Self-healing is a promising strategy to address this problem while constructing the highly effective self-healing catalytic system is still challenging. Here, we explore a simple approach by incorporating high-valence metals of molybdenum (Mo) and tungsten (W) into a cobalt–iron (Co–Fe)-based oxide modulator. A high-entropy layered oxide catalyst, FeCoMoW, is synthesized using a molten-alkali method. The FeCoMoW catalyst exhibits self-healing capabilities, as demonstrated in the chronoamperometric tests at a high potential. It even shows a reduction of overpotential in a borate buffer (KB_i, pH = 14) containing Co²⁺ undergoing a 100 h long-term stability test or enduring 5000 cycles of cyclic voltammetry test. Importantly, the presence of high-valence metals in the high-entropy materials is found to be essential for self-healing behavior, and the two-dimensional morphology of catalysts is conducive to the catalytic performance. This work introduces a feasible strategy to design cost-effective and robust catalysts with self-healing properties, thereby paving the way for more OER applications.