Zn leaching reconstructs high-entropy hydroxyl oxides for efficient OER at large current density

Abstract

The study of oxygen evolution reaction (OER) catalysts is crucial for the development of hydrogen energy technology. However, industrial water splitting requires high current densities, and monometallic catalysts have poor stability at high current densities, so the development of multimetallic high-entropy catalyst has become a focus of attention. Herein, we report an amorphous high-entropy FeCoNiZnOOH electrocatalyst that exhibits exceptional stability during the OER under alkaline conditions for over 150 h at 1 A cm⁻², an industrial current density condition. And after the OER, the catalyst performance was further improved to achieve a current density of 100 mA cm⁻² with only 191 mV overpotential. This phenomenon is attributed to the leaching of Zn, increasing the lattice oxygen content. Meanwhile, the catalyst nanoparticles unfold to form nanoflower-like catalysts, which increases the ECSA of the catalyst. This work provides an exploration of the reconstruction mechanism of high-entropy electrocatalysts, which contributes to the design and development of high performance OER catalysts.