Eco-friendly sacrificial agents-free photocatalytic synthesis of hydrogen peroxide: Recent innovations and future prospects

Onsite generation of hydrogen peroxide (H₂O₂) through photocatalysis without the necessity of sacrificial agents presents a sustainable and eco-friendly option compared to conventional synthesis techniques. In this method, semiconductors act as photo-catalysts, transforming water (H₂O) and oxygen (O₂) into H₂O₂ under light exposure. This eliminates the need for additional chemicals, simplifying the purification process and reducing the formation of unwanted by-products. However, most reported H₂O₂ generation needs sacrificial agent to accelerate the half reaction of H₂O oxidation. This article furnishes a thorough survey of the latest developments in sacrificial agent-free photocatalytic H₂O₂ synthesis. The recent advancements of newly reported photo-catalysts with remarkably efficient oxygen diffusion coefficients that can achieve H₂O₂ from pure water are introduced, and the effects of modification methods such as doping, surface modifications, and the formation of heterojunctions on the light absorption and charge carrier dynamics are discussed. The fundamental mechanisms and prospective research pathways necessary to refine this technology are supposed for practical and industrial purposes.