Porous high-entropy oxide nanosheets as highly-efficient electrocatalysts for water oxidation

Abstract

The controllable regulating strategy of composition and morphology for transition-metal-based high-entropy oxides is of significance for oxygen evolution reaction (OER), but there are still major challenges. Herein, a universal and scalable precursor morphology-oriented strategy is developed to realize the rational synthesis of high-entropy oxides with uniform component distribution. The advantages of those materials with porous nanosheet morphology and high-entropy composition endow their high-efficient catalytic performance for OER. Remarkably, the optimized (FeCoNiCrZn)₃O₄ catalyst shows the best catalytic activity with a small overpotential (216 mV@10 mA cm⁻²), low Tafel slope, excellent stability and high Faradaic efficiency of over 95% for O₂ gas. The experimental studies confirm the improved catalytic active area, reaction kinetics and interfacial behaviors of (FeCoNiCrZn)₃O₄. In situ spectral characterizations reveal its rapid formation of OOH* species and high-valence Ni-based active species for OER, indicating the significant promotion effect of Zn element for excellent catalytic performance. Our strategy offers a novel avenue for developing other advanced high-entropy oxides for energy-related catalytic systems.