Ag/AgBr/WO(3).H(2)O: visible-light photocatalyst for bacteria destruction.

A new composite photocatalyst Ag/AgBr/WO(3).H(2)O was synthesized by reacting Ag(8)W(4)O(16) 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 WO(3).H(2)O and have irregular shapes with sizes varying between 63 and 442 nm. WO(3).H(2)O appears as flakes about 31 nm thick and 157-474 nm wide. The as-grown Ag/AgBr/WO(3).H(2)O sample shows strong absorption in the visible region because of the plasmon resonance of Ag nanoparticles in Ag/AgBr/WO(3).H(2)O. 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/WO(3).H(2)O is a highly efficient photocatalyst under visible light. The Ag/AgBr/WO(3).H(2)O samples recovered from repeated photooxidation experiments are almost identical to the as-prepared samples, proving the stability of Ag/AgBr/WO(3).H(2)O sample.