Synthesis, performance and action mechanism of carbon black/Ag 3 PO 4 photocatalysts

Abstract Novel carbon black (CB)/Ag 3 PO 4 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/Ag 3 PO 4 was evaluated through methyl orange degradation experiments under visible light irradiation. The CB/Ag 3 PO 4 showed higher photocatalytic activity than pure Ag 3 PO 4 . 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/Ag 3 PO 4 was 1.6 times that of Ag 3 PO 4 . And the results of the cyclic experiment show that the photocatalyst has good stability. Moreover, the mechanism about the photocatalytic activity of CB/Ag 3 PO 4 compounds was investigated. In this photocatalytic reaction, •OH was the major active substrate responsible for the visible-light-driven degradation.