Trace water triggers high-efficiency photocatalytic hydrogen peroxide production

Photocatalytic production of hydrogen peroxide(H_(2)O_(2))has attracted much attentions as a promising method for sustainable solar fuel.Here,we demonstrate that trace water can drastically boost highefficiency photocatalytic production of H_(2)O_(2) with a record-high concentration of 113 mmol L^(-1) using alkali-assisted C_(3)N_(4) as photocatalyst in water/alcohol mixture solvents.By electron paramagnetic resonance(EPR)measurement,the radical species generated during the photocatalytic process of H_(2)O_(2) are identified.We propose alcohol is used to provide and stabilize-OOH radicals through hydrogen bond,while trace water could trigger photocatalytic production of H_(2)O_(2) via providing and transferring indispensable free protons to completely consume OOH radicals,which breaks the reaction balance of-OOH radical generation from alcohol.Thus-OOH radicals could be supplied by alcohol continuously to serve as a reservoir for high-efficiency production of H_(2)O_(2).These results pave the way towards photocatalytic method on semiconductor catalysts as an outstanding approach for production of hydrogen peroxide.