Gold-autocatalyzed synthesis of high-entropy oxides for robust oxygen evolution reactions

High-entropy oxides (HEOs) are an emerging class of materials with tunable compositions and complex solid-solution structures, making them promising for a wide range of fields, particularly for electrocatalytic applications such as water electrolysis. However, a key challenge in synthesizing HEO lies in the requirement for harsh conditions, which restricts their practical applications. Herein, we present a gold-autocatalyzed synthesis method to fabricate compositionally adjustable HEOs under mild reaction conditions, accompanied by the uniform dispersion of metallic Au within the HEO matrix. The strong electrophilicity of Au and high oxidation potential of Cr decrease the formation temperature of HEOs, facilitating the large-scale production of compositionally adjustable HEOs. In addition, the as-prepared Au/HEO catalyst exhibits a low overpotential of 275 mV to deliver 100 mA cm −2 and long-term durability during the stability test for over 1000 h at 100 mA cm −2 . Remarkably, when utilized in an anion exchange membrane water electrolyzer (AEMWE), the Au/HEO catalyst displays excellent stability with a degradation rate of 57.6 μVh −1 during 500 h of continuous working. The reconstruction of HEO is effectively modulated by negatively charged Au, contributing to the long-term stability of the Au/HEO catalyst. This work offers a new perspective for designing and synthesizing high-entropy materials for practical applications.