Status and challenges of photocatalysis in environmental applications: Photocatalyst deactivation

Photocatalytic technology, often termed as the “Holy Grail of science”, has gained significant attention for addressing energy shortages and environmental crises. This technology is widely applied in environmental purification due to its ability to absorb solar energy, convert it into chemical energy, promote reactions, all while offering a non-polluting, highly effective means of mineralizing pollutants. However, despite extensive studies, photocatalysis has not yet to meet the practical demands for widespread application. One main key challenge that hinders the effective use of photocatalysis in environmental applications is catalyst deactivation. Therefore, a systematic review of the literature on photocatalysis in environmental applications is presented, with a classification based on photocatalytic materials and pollutant types. The review paper begins by summarizing the primary mechanisms of catalyst deactivation, followed by a summary of regeneration strategies tailored to these mechanisms. Various methods for assessing the degree of photocatalyst deactivation are also discussed, with emphasis on their relationship to photocatalytic reaction mechanisms. The review then highlights recent advances in the development of anti-deactivation photocatalysts and their applications in environmental purification. Finally, the current status of the field, the challenges that remain, and potential directions for future research are outlined to enhance the efficacy of photocatalytic processes in environmental applications.