Defect pyrochlore oxides: as photocatalyst materials for environmental and energy applications ‐ a review

Photocatalytic technology utilizing abundant solar light holds great promise to tackle many challenging environmental and energy issues. In recent years, various types of photocatalysts have been developed that are active for environmental purification and hydrogen production. Papers reporting preparation, characterization and photocatalytic testing of binary, ternary and quaternary compounds have been reviewed. The present review focuses on photocatalyst materials which adopt a defect pyrochlore structure. Starting with a brief introduction to semiconductor‐based photocatalysts for environmental clean‐up and hydrogen generation from water splitting, the development of high‐efficiency UV and visible light driven photocatalysts belonging to the defect pyrochlore family is reviewed. The review covers all the defect pyrochlore photocatalysts studied so far, and provides guidance to researchers in this area for further investigation of these materials.