Photocatalytic Water Splitting and H2 Generation Coupled with Organic Synthesis: A Large Critical Review

Photocatalytic water splitting using natural solar light is considered as a sustainable approach to generate H2 and O2. While H2 has high market value, the by-product of water splitting, oxygen, is less valuable. To make H2 produced by means of photocatalysis more economically competitive to that generated from methane, its generation is studied together with synthesis of organic compounds that have higher market value. This review summarizes and analyzes critically dehydrogenation reactions that were developed since 1980s. Photocatalytic dehydrogenation reactions are classified and the results are collected in the online database. Performance of homogeneous and heterogenous photocatalysts in dehydrogenation reactions, such as yield rates of organic products on analytical and preparative scales, and quantum efficiencies are compared. Current limitations of the existing methods and photocatalytic systems are identified and directions for the future developments are outlined.