The Positive Versus Negative Effects of Defect Engineering for Solar Water Splitting: A Review

Abstract Although defect design is an essential means of improving the performance of photocatalytic materials, defect introduction is not always beneficial. Current defect engineering focuses on avoiding or modifying introduced defects to mitigate their adverse effects on solar water splitting performance. This review comprehensively summarizes the strategies for defect introduction and discusses their crucial roles in solar water splitting. Focusing on the dual effects of defects, the most basic schemes for preparing favorable defects through pretreatment and posttreatment methods are reviewed. In addition, the review focuses on strategies for overcoming or mitigating the detrimental effects of defects to improve the performance of photocatalysts. Finally, the challenges and prospects of developing a defect‐based photocatalyst design strategy are outlined. This review provides a reference for preparing defect‐based photocatalysts for conducting more in‐depth research on defects. Additionally, it offers ideas for utilizing unfavorable defects and converting them into favorable defects for performance improvement.