Organic Transformations Involving Photocatalytic Hydrogen Release

A switch from a fossil-based energy sector to sustainable energy sources has become one of the pressing requirements of modern society. In this context, the role of molecular hydrogen (H2) as a green energy carrier has gained a central role in the energy transition. The exploitation of pure visible light for hydrogen production, in which solar energy is converted into chemical energy by means of a photocatalyst and an appropriate hydrogen source, represents an appealing way to produce this valuable energy vector. Moreover, photocatalytic H2 evolution reactions can be coupled with a wide range of selective organic transformations, such as oxidation of alcohols and coupling reactions, in order to achieve dual functionality, simultaneously yielding clean H2 and value-added chemicals. Cooperative organic synthesis and H2 production represent an attractive and growing branch of photocatalysis in the last decade, but many efforts still need to be invested in. A considerate choice and effective optimization of suitable heterogeneous photocatalysts for these dual-functional processes are of crucial importance to overcome low efficiencies and identify cost-effective industrial applications.