Clean Production of Hydrogen Peroxide: A Heterogeneous Solar-Driven Redox Process

Hydrogen peroxide is an essential chemical that is attracting strong attention for energy and environmental applications. However, the struggle between the growing market demand and the unsustainability of the conventional anthraquinone method motivates the exploration of alternative H₂O₂ production processes. Although several new production processes have been proposed, the environmental-friendly solar-driven H₂O₂ production attracts most attention because of the only inputs of water, oxygen, and light energy. The rational design of functional photo-responsive catalysts promotes H₂O₂ production in the photocatalytic and photoelectrocatalytic approaches. These are, in general, achieved by facilitating the preferential adsorption of key intermediates of OOH*/OH*/O*, enhancing the light absorption, promoting the charge separation, and accelerating the surface charge transfer with selective number of involved charges. This review systematically summarizes strategies for photo(electro)catalysts toward H₂O₂ production via both the water oxidation and oxygen reduction pathways. Though the oxygen reduction route is perceived as more popular in the community, selective water oxidation is emerging as a convincing alternative. Furthermore, prevailing hypotheses, state-of-the-art catalysts, critical challenges, and perspectives are discussed in depth. This review aims to enhance the comprehension of this research field and promote interest in sustainable H₂O₂ production.