Synthesis, performance and action mechanism of carbon black/Ag3PO4 photocatalysts

Novel carbon black (CB)/Ag3PO4 compound photocatalysts were synthesized from a hydrothermal method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and electrochemical methods. The photocatalytic oxidation ability of CB/Ag3PO4 was evaluated through methyl orange degradation experiments under visible light irradiation. The CB/Ag3PO4 showed higher photocatalytic activity than pure Ag3PO4. It was indicated the compound catalysts could absorb and utilize more optical energy to improve the photocatalytic activity, which was attributed to the ability of carbon black to accelerate the electron-hole separation. In particular, the methyl orange photocatalytic degradation rate over the 7 mg/L CB/Ag3PO4 was 1.6 times that of Ag3PO4. And the results of the cyclic experiment show that the photocatalyst has good stability. Moreover, the mechanism about the photocatalytic activity of CB/Ag3PO4 compounds was investigated. In this photocatalytic reaction,
- OH was the major active substrate responsible for the visible-light-driven degradation.