High-entropy oxides for catalysis: from entropy-stabilized lattices to multi-functional reaction platforms

Abstract

High-entropy oxides (HEOs), featuring multiple metal cations randomly distributed within a single solid-solution lattice, have recently emerged as a versatile platform for heterogeneous catalysis. Enabled by high configurational entropy, HEOs exhibit exceptional structural stability, pronounced lattice distortion, and diverse local electronic environments, fundamentally distinguishing them from conventional oxides. This review provides a critical overview of HEOs for catalytic applications, focusing on mechanistic origins, synthesis strategies, and representative reactions. We discuss the collective role of entropy-induced disorder, lattice distortion, sluggish diffusion, and multi-cation synergy in generating statistically distributed active sites and stabilizing reactive intermediates. Recent advances in HEO synthesis and structural engineering are summarized, highlighting routes to control phase stability, defects, and morphology. Representative applications in thermocatalysis, electrocatalysis and photocatalysis are reviewed, revealing the governing roles of entropy-enabled electronic modulation and dynamic surface reconstruction in catalytic performance. We further highlight HEOs as robust supports for single-atom catalysts to enhance catalytic activity and stability and also summarize emerging theoretical and machine-learning-driven approaches for accelerating rational design across the vast high-entropy compositional space. Overall, HEOs represent a paradigm shift in catalyst design, where controlled compositional complexity and structural disorder are harnessed to achieve robust and adaptable catalytic systems.