Current Developments and Future Trends in Photocatalytic Glycerol Valorization: Photocatalyst Development

Glycerol is a significant byproduct of biomass conversion into biodiesel, and numerous studies have been focused on its valorization technologies in recent years. Photocatalytic glycerol valorization is a promising technology to convert solar energy into chemical energy by producing hydrogen and value-added liquid products. This technology is desirable from the point of view of both green chemistry and sustainable development since it can operate at ambient temperature and atmospheric pressure by using renewable solar energy. The key element for a successful photocatalytic glycerol valorization process is the development of highly active and stable photocatalysts. In this context, the present review deals with novel techniques to improve photocatalysts' activity. It reviews the main characteristics, preparation methods, advantages, and drawbacks as well as the performance of different TiO2-based and non-TiO2-based photocatalysts for glycerol conversion. Also, an analysis is presented on the most effective approaches for increasing the photocatalytic activity, including cocatalyst deposition, doping with metallic and nonmetallic ions, development of carbonaceous composites, and formation of heterojunctions. The review also offers the readers ongoing challenges and opportunities for research on photocatalyst development to selectively convert glycerol into hydrogen and value-added liquid products.