Strategies and Challenges on Selectivity of Photocatalytic Oxidation of Organic Substances

Most organic compounds are conventionally synthesized under high temperature and elevated pressure, resulting in significant energy consumption and wastage. Heterogeneous photocatalytic oxidation has the potential to provide a green route for the synthesis of the majority of industrially important chemicals. The major limiting factor affecting the efficiency of photocatalytic organic synthesis is the lack of high selectivity; therefore, substantial effort has been devoted to solving this problem. Responding to this fast-moving progress, this review gives an overview of the fundamental understanding of the reactive oxygen species involved in photocatalytic organic oxidations and furthermore, the general mechanisms of a few crucial oxidation reactions. The focus of this critical review is on the discussion of diverse strategies to improve the selectivity of high value chemicals, including band engineering, metal loading, hybrid materials, and defect engineering, with the primary aim of highlighting the catalyst design protocols based on the reaction mechanism. Finally, the difficulties and challenges of developing highly selective oxidation photocatalysts are comprehensively discussed in order to help direct the focus of future research.