Enhanced plasmonic photocatalytic synthesis of hydrogen peroxide at an air-liquid-solid triphasic interface

Photocatalysis is a promising green approach for H2O2 synthesis. Au nanoparticles decorated TiO2 (Au-TiO2) is a visible light active photocatalyst and has received great attentions recently, but the photocatalytic efficiency has been restricted, especially under visible light irradiation. We describe here an efficient triphasic photocatalytic system for visible light driven synthesis of H2O2 using Au-TiO2. This system allows the photocatalytic reaction to be carried out at an air-liquid-solid triphasic interface, in which sufficient reactant O2 can be directly delivered from the ambient atmosphere, greatly enhancing its concentration at the reaction zone. Based on the triphasic photocatalytic system we found that the reaction kinetics and the steady-state H2O2 concentration was much enhanced, and only one-tenth of the light intensity is needed to achieve a comparable H2O2 formation rate compared with the traditional diphase system. The triphase system provides an exploratory platform for further understanding of the intrinsic photocatalyst kinetics and plasmonic mechanism.