Unlocking the potential of metastable-phase catalysts: advantages, stabilization, and applications

Metastable-phase catalysts have emerged as a promising class of materials thanks to their excellent catalytic performance, stemming from their high Gibbs free energy, unique electronic structures, specific morphologies, and distinctive coordination environments. However, the development of metastable-phase catalysts still face great challenges due to their native thermodynamical instability, calling for innovative synthetic methods and catalyst design strategies. This review focuses on the advantages, stability enhancement strategies, main categories, and diverse applications of metastable-phase catalysts. We begin with the advantages of metastable-phase materials for designing high-performance catalysts, followed by a discussion of the latest advancements in stabilizing these materials through low-dimensional strategies, doping, core–shell structures, substrate effects and high-entropy strategies. Subsequently, we systematically classify and discuss in detail the structures and properties of several recently discovered metastable-phase materials. In addition, we examine their applications in electrocatalysis, hydrogenation and dehydrogenation reactions, as well as other applications. Finally, we provide insights into the future research directions to unlock the full potential of metastable-phase materials.