Efficient visible-light activation of molecular oxygen to produce hydrogen peroxide by P doped g-C3N4 hollow sphere

Graphitic carbon nitride (g-C3N4) possesses unique electronic and optical properties in the visible-light-driven production of H2O2. However, bulk g-C3N4 suffers from inefficient sunlight absorption and low carrier mobility. Herein, P doped g-C3N4 with a hollow sphere architecture was synthesized. The hollow sphere structure provides a large accessible surface area for charge transfer and enhances photo-absorption properties. Particularly, the doped P can regulate the energy band structure with stronger reducibility for O2 activation and accelerate photo-generated carrier separation. Meanwhile, the P heteroatom is beneficial to produce 1,4-endoperoxide species more easily and enhance selectivity for H2O2 synthesis through a two-electron O2 reduction process. The resultant catalyst exhibits a high H2O2 production rate of 174 μmol h−1 g−1 in pure water and 1684 μmol h−1 g−1 with isopropanol as a hole scavenger, which are 7.5 and 11.2 times those of bulk g-C3N4. This work provides a new avenue for the design and modification of other photocatalysts for H2O2 production.