Ceria-based photocatalysts in water-splitting for hydrogen production and carbon dioxide reduction

The design and application of semiconductor-based photocatalytic technology has a significant impact on addressing the world's energy crisis and environmental degradation by transforming solar energy into chemicals and fuels. Semiconductor-based photocatalyst, ceria (CeO2), which possesses unique 4f electrons, is superior to other metal oxide semiconductors owing to its defect-rich structure, multivalence state, surface oxygen vacancy, photostability, and eco-friendly properties. This critical review is taken up to report the basic mechanistic details of CeO2-based photocatalysis as well as several methods for boosting the activity and stability of this group of photocatalysts. Additionally, numerous photocatalytic applications of CeO2, such as H2 generation by water splitting and CO2 reduction to alcohols and hydrocarbon fuels, are introduced and summarized. In the end, a concise summary of the challenges and potential areas for future research in the synthesis of CeO2-based photocatalysts are also provided. This review is anticipated to provide directions for developing innovative CeO2-based photocatalysts with low-cost and high efficiency, which have the promising application possibilities to fulfill the pressing needs of alternative fuels.