Challenges and prospects of photocatalytic H2O2 production

Hydrogen peroxide (H2O2) is one of the 100 most important chemicals used extensively in bleaching, disinfection, and synthetic chemistry industries. It is currently used as a fuel in direct fuel cells. The current H2O2 production relies on the harsh anthraquinone oxidation approach. Photocatalytic H2O2 production is a more favorable alternative from environmental, sustainability, and economic viewpoints. The process requires water and molecular oxygen as inputs and sunlight as the sole power source. Despite these merits, the practical application of this technology remains challenging. The most common bottlenecks are the photocatalyst's inadequacy, uphill thermodynamics, sluggish process kinetics, and competitive and backward reactions. This paper discusses these limitations and highlights the proposed perspectives to improve the efficiency and selectivity, aiming to pave the way toward large-scale H2O2 photogeneration.