Recent Advances in Crystalline-Amorphous Heterointerface Engineering of High-Entropy Oxides for Oxygen Evolution Catalysis

Abstract

High-entropy oxides (HEOs) have demonstrated great potential in enhancing the activity and stability of oxygen evolution reaction (OER) catalysts for water electrolysis, owing to their entropy-stabilization effect, lattice distortion, and multi-element synergistic effects. However, their inherently low electrical conductivity severely limits further improvements in catalytic efficiency. In recent years, constructing crystalline–amorphous heterointerfaces has emerged as a promising strategy to compensate for the conductivity deficiency of HEOs. Such heterostructures not only accelerate charge transfer via localized electronic reconstruction at the interfaces but also provide abundant catalytic active sites through the numerous dangling bonds and structural defects present in the amorphous regions, thereby achieving a synergistic optimization between activity and conductivity, and significantly boosting OER performance. This review begins with a brief overview of the fundamental definition of HEOs, followed by an in-depth discussion on the structural characteristics of crystalline–amorphous interfaces and their modulation mechanisms on the electronic structure. We then systematically summarize the main strategies for constructing heterointerfaces, including electrodeposition, Joule heating, and combustion synthesis. Subsequently, we highlight the regulatory effects of heterointerfaces on catalytic performance and OER reaction pathways. Finally, we conclude by identifying the key challenges in this field and offering perspectives on future research directions.