Improved photocatalytic H2O2 production of boron doped g-C3N4 by controllably co-modifying nanosized PDI and Ag

Herein, boron-doped g-C3N4 (BCN) is first modified with perylene diimide (PDI) nanosheets driven by the π−π interactions, and subsequently decorated with nanosized Ag through the photodeposition method. The optimal PDI/BCN-Ag photocatalyst achieves a H2O2 production rate of 143 μmol g−1 h−1 without any sacrificial agents under visible light irradiation, which is about13-fold improvement compared with pristine g-C3N4. The boosted photoactivity is mainly ascribe to the enhanced charge separation due to the cascade S-scheme charge transfer between the coupled PDI and BCN, and the promoted oxygen activation from the introduced nanosized Ag by means of the time-resolved surface photovoltage responses and fluorescence spectra, kelvin probe measurement analyses, O2 temperature-programmed desorption and electron paramagnetic resonance spectroscopy. Notably, there is a dual channel for H2O2 production on PDI/BCN-Ag. The two-electron oxygen reduction dominated by the produced •O2− radicals occurs on the Ag nanoparticles, whereas the two-electron water oxidation occurs on the PDI.