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

A new composite photocatalyst Ag/AgBr/WO3 center dot 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 center dot H2O and have irregular shapes with sizes varying between 63 and 442 nm. WO3 center dot H2O appears as flakes about 31 nm thick and 157-474 nm wide. The as-grown Ag/AgBr/WO3 center dot H2O sample shows strong absorption in the visible region because of the plasmon resonance of Ag nanoparticles in Ag/AgBr/WO3 center dot H2O. The ability of this compound to destroy E. coli and oxidize methylic orange under visible light was compared with those of other reference photocaltalysts. Ag/AgBr/WO3 center dot H2O is a highly efficient photocatalyst under visible light. The Ag/AgBr/WO3 center dot H2O samples recovered from repeated photooxidation experiments are almost identical to the as prepared samples, proving the stability of Ag/AgBr/WO3 center dot H2O sample.