Ag/AgBr/WO3·H2O: Visible-Light Photocatalyst for Bacteria Destruction

Abstract

A new composite photocatalyst Ag/AgBr/WO₃·H₂O was synthesized by reacting Ag₈W₄O₁₆ with HBr and then reducing some Ag⁺ ions in the surface region of AgBr particles to Ag nanoparticles via the light-induced chemical reduction. Ag nanoparticles are formed from AgBr by the light-induced chemical reduction reaction. The Ag/AgBr particles are on the surface of WO₃·H₂O and have irregular shapes with sizes varying between 63 and 442 nm. WO₃·H₂O appears as flakes about 31 nm thick and 157−474 nm wide. The as-grown Ag/AgBr/WO₃·H₂O sample shows strong absorption in the visible region because of the plasmon resonance of Ag nanoparticles in Ag/AgBr/WO₃·H₂O. The ability of this compound to destroy E. coli and oxidize methylic orange under visible light was compared with those of other reference photocatalysts. Ag/AgBr/WO₃·H₂O is a highly efficient photocatalyst under visible light. The Ag/AgBr/WO₃·H₂O samples recovered from repeated photooxidation experiments are almost identical to the as-prepared samples, proving the stability of Ag/AgBr/WO₃·H₂O sample.