Etching engineering for high-performance photocatalysts: from mechanistic insights to strategic design and practical applications.

Photocatalysis has attracted considerable interest as a sustainable and environmentally friendly technology for energy conversion and environmental remediation. However, the applications of photocatalysts are often affected by rapid recombination of photogenerated charge carriers, limited stability, and sensitivity to photocorrosion. As an effective strategy for material engineering, etching provides a powerful method to enhance photocatalytic performance by controlling catalyst morphology, regulating charge separation and transport, and modifying interfacial characteristics. Although etching has been widely adopted for modifying photocatalysts, a systematic overview focusing on its specific effects is still lacking. This review presents the fundamental principles of photocatalysis and various photocatalysts, with specific emphasis on different etching methods and etching strategies. It also systematically emphasizes the important role of etching in optimizing photocatalysts. Additionally, it clarifies how different etching methods influence the structure and performance of the photocatalysts, and deeply explores the impact of etching at different scales. Finally, we outline the current challenges and future prospects of etching-based strategies in photocatalysis. This review aims to provide innovative design principles for efficient and stable photocatalysts, thereby facilitating substantive progress in renewable energy and environmental remediation.