Rapid joule heating synthesis of oxygen-vacancy-rich high-entropy oxide as a high-performance electrocatalyst for OER

High–entropy oxide (HEO) are highly efficient electrocatalysts for the oxygen evolution reaction (OER), meeting the criteria for low cost, high activity, and long–term stability. This enhanced efficiency originates from their multicomponent composition and the synergistic interactions among the constituent elements. However, their inherent low conductivity and the lack of effective synthesis methods remain challenges. In this study, highly dispersed nanoscale spinel–type oxides (Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 Cr 0.2 ) 3 O 4 /CC, were prepared on carbon cloth (CC) through rapid one–step electrodeposition at room temperature, combined with Joule heating (JH), abbreviated as JH-HEO/CC. The introduction of abundant oxygen vacancies by JH's 'instantaneous–non–equilibrium' characteristic enhances ionic conductivity and optimizes reaction pathways. Thanks to these defects, the unique 'cocktail' effect allows these HEO to deliver a current density of 10 mA·cm −2 at an overpotential of 282 mV, while demonstrating excellent stability. This study establishes effective synthetic and modification strategies for high-performance OER electrocatalysts.