Microwave- and Formaldehyde-Assisted Synthesis of Ag–Ag₃PO₄ with Enhanced Photocatalytic Activity for the Degradation of Rhodamine B Dye and Crude Oil Fractions

Abstract

The release of crude oil and water-soluble dyes into our marine environment is a major global problem. An efficient semiconductor Ag-Ag₃PO₄ photocatalyst was synthesized using formaldehyde as a reducing agent to form surface active Ag on Ag₃PO₄ under microwave radiation for heating, and its potential in destroying environmental pollutants has been examined. The diffuse reflectance spectroscopy of Ag-Ag₃PO₄ revealed an enhanced absorption in the visible light region. The rate of photocatalytic degradation of rhodamine B by Ag-Ag₃PO₄ was over 4-fold compared to Ag₃PO₄. The potential application of Ag-Ag₃PO₄ in oil spill remediation was also examined through photocatalytic degradation of benzene, <i>n</i>-hexane, and 1:1 v/v benzene/methanol crude oil-soluble fractions. UV-vis and gas chromatography-mass spectrometry analysis of the crude oil components after visible light irradiation showed excellent degradation. The photocatalytic efficiency enhancement of Ag-Ag₃PO₄ is attributed to the excellent electron trapping of silver nanoparticles deposited on the surface of Ag₃PO₄. This work will motivate future studies to develop recyclable visible light photocatalysts for many applications.