Preparation of sodium and boron co-doped graphitic carbon nitride for the enhanced production of H2O2 via two-electron oxygen reduction and the degradation of 2,4-DCP via photocatalytic oxidation coupled with Fenton oxidation

This study reported the preparation of sodium and boron co-doped graphitic carbon nitride (NaB-CN) for H2O2 production via photocatalytic oxygen reduction and 2,4-dichlorophenol (2,4-DCP) degradation via photocatalytic oxidation coupled with Fenton oxidation. Various characterization techniques have been utilized to study the crystal structure, surface morphology, elemental composition and photoelectric properties of the photocatalysts. It was found that Na and B co-doping evidently enhanced the photocatalytic performance of graphitic carbon nitride for H2O2 production and 2,4-DCP degradation attributed to the effective enhancement in light absorption, electron-hole (e–-h+) pairs separation and charge carrier mobility. The optimized NaB-CN presented the H2O2 production rate of 22.3 mg L-1h−1 in ethanol aqueous solution (1.0 vol%) under visible light irradiation, which was about 15 times that of the un-doped graphitic carbon nitride (g-C3N4). One important and interesting result obtained was that 2,4-DCP and some degradation intermediates could act as electron donors to promote H2O2 production during the photocatalytic degradation of 2,4-DCP, which allowed the application of Fenton oxidation to further enhance degradation performance after photocatalytic oxidation without adding H2O2 externally. The results of this work indicate the recommended photocatalyst possesses relatively stable and appreciable photocatalytic activity, exhibiting its great potential in industrial application for H2O2 production and organic pollutants degradation.