An Overview of the Emergent Field of High‐Entropy Oxides for Photocatalytic Dye Degradation

High‐entropy oxides (HEOs) are a promising class of novel ceramic materials characterized by their complex chemistry and multifunctionality. By leveraging high configurational entropy, HEOs stabilize single‐phase structures with significant lattice distortion and tuneable electronic properties through the incorporation of multiple metal cations. This versatility makes HEOs particularly relevant for photocatalytic applications, such as dye degradation in wastewater treatment. This review explores the advancements in HEO catalysts for photocatalysis, detailing their evolution from alloys to ceramics and the thermodynamic principles that influence phase stabilization. Key distinctions between HEOs and traditional oxides are highlighted, along with the significant capabilities of HEO photocatalysts to address challenges posed by conventional systems. The article explores the crystal structure, synthesis methods, and material design for enhanced charge separation and light absorption. It compares the performance of various HEO photocatalysts and discusses their advantages over single or binary‐oxide alternatives. Finally, the review identifies critical knowledge gaps, such as the quantitative effects of entropy, and suggests future directions involving operando characterization, first‐principles modeling, and machine learning for the rapid development of next‐generation HEO materials.