Efficient photocatalytic H2O2 production from oxygen and pure water over graphitic carbon nitride decorated by oxidative red phosphorus

Abstract

Photocatalytic H2O2 production in pure water is prerequisite for diverse on-site applications, but challengeable to be realized owing to sluggish water oxidation and significant recombination of photogenerated charges. Herein, efficient photocatalytic H2O2 production in pure water was realized on graphitic carbon nitride (GCN) decorated by oxidative red phosphorus (ORP). The composite produces 250 μM of H2O2 within 120 min under visible light irradiation via synchronous water oxidation and oxygen reduction reactions, which is more than 25-fold enhancement of pristine GCN. It is revealed that red phosphorus (RP) can significantly promote charge separation but induce reductive decomposition of H2O2. Successfully, H2O2 decomposition over RP is dramatically suppressed by preventing the interaction between H2O2 and P atoms through oxidizing RP with the formation of PO bonds by an oxidation post-treatment. This strategy opens a new door for the rational design of highly active metal-free photocatalysts toward solar-to-H2O2 conversion in pure water.