Synthesis of a novel and stable g-C₃N₄–Ag₃PO₄ hybrid nanocomposite photocatalyst and study of the photocatalytic activity under visible light irradiation

A facile and reproducible template free in situ precipitation method has been developed for the synthesis of Ag₃PO₄ nanoparticles on the surface of a g-C3N4 photocatalyst at room temperature. The g-C₃N₄–Ag₃PO₄ organic–inorganic hybrid nanocomposite photocatalysts were characterized by various techniques. TEM results show the in situ growth of finely distributed Ag₃PO₄ nanoparticles on the surface of the g-C₃N₄ sheet. The optimum photocatalytic activity of g-C₃N₄–Ag₃PO₄ at 25 wt% of g-C₃N₄ under visible light is almost 5 and 3.5 times higher than pure g-C₃N₄ and Ag₃PO₄ respectively. More attractively, the stability of Ag3PO4 was improved due to the in situ deposition of Ag₃PO₄ nanoparticles on the surface of the g-C₃N₄ sheet. The improved performance of the g-C₃N₄–Ag₃PO₄ hybrid nanocomposite photocatalysts under visible light irradiation was induced by a synergistic effect, including high charge separation efficiency of the photoinduced electron–hole pair, the smaller particle size, relatively high surface area and the energy band structure. Interestingly, the heterostructured g-C₃N₄–Ag₃PO₄ nanocomposite significantly reduces the use of the noble metal silver, thereby effectively reducing the cost of the Ag₃PO₄ based photocatalyst.