Abstract
A series of Ag3PO4/Ag2W2O7 heterojunction composite photocatalyst with ascending Ag2W2O7 content (W loading 0-30%) were synthesized through one-shot coprecipitation technique and characterized by XRD, SEM, Raman and DR UV-Vis spectroscopy. The photocatalytic activity of the synthesized samples was evaluated by the photocatalytic decolorization of methyl orange (MO) dye under visible light illumination and compared with that of neat Ag3PO4. Ag3PO4/Ag2W2O7 heterojunction composite with W loading 10% exhibited the highest photocatalytic activity, in which 65% of MO was decolorized after 10 min, versus 9% in the case of neat Ag3PO4. Moreover, the apparent rate constant of MO decolorization in the case of Ag3PO4/Ag2W2O7 composite was 7.2 times higher than neat Ag3PO4. However, Ag3PO4/Ag2W2O7 heterojunctions with W loadings exceeding 10% showed lower photocatalytic efficiency, most likely, due to increasing Ag2W2O7 content in the composite which shields Ag3PO4 surface and restricts the photocatalytic process. The enhancement in the photocatalytic activity of the prepared samples was attributed to the effective separation of photogenerated electron-hole pairs as a result of the formed heterojunction between Ag3PO4 and Ag2W2O7 in the composite. The formed Ag3PO4/Ag2W2O7 heterojunction showed a shift of the optical absorption edge of Ag3PO4 to longer wavelengths. Thus, it can be concluded that Ag3PO4/Ag2W2O7 heterojunction composite with W loading of 10% is a promising photocatalyst in visible light illumination for industrial wastewater treatment.