Applications of solar-driven interfacial evaporation-coupled photocatalysis in water treatment: A mini review

Solar-driven interfacial evaporation technology (SDIE) was previously proposed to produce freshwater in seawater desalination. With the environmentally-friendly merit of solar energy, researchers tried to apply this technology in other water treatments. However, the components in different water matrices are complex, various contaminants accumulate on the interface reducing evaporation efficiency or evaporating with water vapor affecting the produced water quality. The photocatalysis has good performance on the removal of these pollutants in water. Since both processes require the participation of light, researchers have proposed coupling solardriven interfacial evaporation with photocatalysis to better solve the problem in water treatment. This review summarizes the application of the coupled processes in water treatment. Firstly, the mechanisms of interfacial photothermal conversion and photocatalytic degradation of pollutants are reviewed. Subsequently, the applications of the coupled processes in water production, contaminants removal, and disinfection for water treatment are summarized. The results show that the condensate collected through the coupled process meets drinking water quality standards. Additionally, the coupled process significantly degrades volatile organic compounds (VOCs), non-volatile organic compounds (NVOCs), and disinfects bacteria, thereby preventing surface contamination at the photothermal interface. Furthermore, the application of the coupled processes for green fuel production from water treatment is also discussed. This production process is based on water-catalyzed hydrogen production and carbon dioxide reduction. Finally, current challenges and future perspectives of the coupled processes are examined, aiming to provide theoretical foundations for future research in this field.