Enhanced photocatalytic activity of Ag3PO4 for oxygen evolution and Methylene blue degeneration: Effect of calcination temperature

Abstract

In this work, Ag3PO4 photocatalysts were prepared via coprecipitation method followed by high temperature calcination. The physicochemical properties of received Ag3PO4 photocatalysts were systematically investigated by using X-ray diffraction, ultraviolet–visible diffuse reflection spectroscopy, scanning electron microscopy, transmission electron microscopy, specific surface area, X-ray photoelectron spectroscopy and electrochemical measurements. The high temperature calcination induces the improvement of crystallinity, the increase of oxygen vacancies, and the decrease of specific surface area of Ag3PO4. The activities of Ag3PO4 towards photocatalytic oxygen evolution and Methylene blue degeneration were found to be highly dependent on the calcination temperature. The Ag3PO4 annealed at 400 °C exhibits the highest photocatalytic oxygen evolution of 87.6 μmol g−1 h−1, which is ca. 4 times higher than that of Ag3PO4 obtained by coprecipitation method. Moreover, the Ag3PO4 annealed at 400 °C demonstrated the best photocatalytic degeneration of Methylene blue (MB) under visible light. The variation of physicochemical properties including crystallinity, oxygen vacancies and specific surface area of Ag3PO4 should be responsible for the enhanced photocatalytic activities. The present work opens an avenue to construct efficient Ag3PO4-based photocatalysts by high temperature calcination.