Synthesis of Ag3PO4/Ag/g-C3N4 Composite for Enhanced Photocatalytic Degradation of Methyl Orange

Abstract

In this study, we have successfully constructed Ag₃PO₄/Ag/g-C₃N₄ heterojunctions via the hydrothermal method, which displays a wide photo-absorption range. The higher photocurrent intensity of Ag₃PO₄/Ag/g-C₃N₄ indicates that the separation efficiency of the photogenerated electron-hole pairs is higher than that of both Ag₃PO₄ and Ag/g-C₃N₄ pure substances. It is confirmed that the efficient separation of photogenerated electron-hole pairs is attributed to the heterojunction of the material. Under visible light irradiation, Ag₃PO₄/Ag/g-C₃N₄-1.6 can remove MO (~90%) at a higher rate than Ag₃PO₄ or Ag/g-C₃N₄. Its degradation rate is 0.04126 min^-1, which is 4.23 and 6.53 times that of Ag/g-C₃N₄ and Ag₃PO₄, respectively. After five cycles of testing, the Ag₃PO₄/Ag/g-C₃N₄ photocatalyst still maintained high photocatalytic activity. The excellent photocatalysis of Ag₃PO₄/Ag/g-C₃N₄-1.6 under ultraviolet-visible light is due to the efficient separation of photogenerated carriers brought about by the construction of the Ag₃PO₄/Ag/g-C₃N₄ heterostructure. Additionally, Ag₃PO₄/Ag/g-C₃N₄ specimens can be easily recycled with high stability. The effects of hydroxyl and superoxide radicals on the degradation process of organic compounds were studied using electron paramagnetic resonance spectroscopy and radical quenching experiments. Therefore, the Ag₃PO₄/Ag/g-C₃N₄ composite can be used as an efficient and recyclable UV-vis spectrum-driven photocatalyst for the purification of organic pollutants.

Keywords: A3PO4/Ag/g-C3N4; methyl orange; photocatalyst.