Highly Efficient Visible Light Plasmonic Photocatalysts Ag@Ag(Cl,Br) and Ag@AgCl-AgI

New plasmonic photocatalysts Ag@Ag(Cl,Br) and Ag@AgCl-AgI were synthesized by the ion-exchange process between AgCl and a potassium halide (KBr, KI), then by reducing some Ag+ ions in the surface region of Ag(Cl,Br) and AgCl-AgI particles to Ag-0 species. The Ag nanoparticles were formed from Ag(Cl,Br) and AgCl-AgI by a light-induced chemical reduction. The Ag@Ag(Cl,Br) and Ag@AgCl-AgI particles have irregular shapes and their sizes vary between 100 nm and 1.3 mu m. The as-grown plasmonic photocatalysts show strong absorption in the visible-light region, owing to the plasmon resonance of Ag nanoparticles. The ability of this compound to oxidize methylic orange and reduce Cr-VI under visible light was compared with those of other reference photocatalysts. These plasmonic photocatalysts have been