Polyoxometalate photocatalysts for sustainable reactions.

Polyoxometalates (POMs) are a class of nanoscale metal-oxygen clusters characterized by well-defined structures and highly tunable electronic properties. These attributes have led to their recent recognition as materials with immense potential for photocatalysis applications. This review systematically summarizes the latest research progress in POM photocatalysts, with a focused discussion on their applications in four key sustainable processes: photocatalytic water splitting for hydrogen and oxygen evolution, photocatalytic carbon dioxide reduction, photocatalytic transformations of organic molecules, and pollutant degradation. Through an in-depth analysis of the structure-property relationships, this article highlights the unique advantages of POMs, particularly their ability to expand the visible-light response, enhance charge carrier separation efficiency via their "electron-sponge" behavior and multi-electron redox processes, and improve overall catalytic stability. Finally, this review critically assesses the current challenges and outlines future research directions for POM photocatalytic materials. This work aims to provide insightful theoretical references and design principles for the development of efficient, stable, and practical POM systems for advanced solar energy conversion.