One-pot synthesis of visible-light-responsive titanium oxide photocatalyst with embedded silver nanoparticles

A composite powder of titanium oxide and silver nanoparticles was obtained by using a combination of the sol–gel process and ultraviolet light induced reduction of silver ion via one-pot synthesis. After calcination, silver nanoparticles were embedded in an anatase crystalline titanium oxide matrix, as revealed by transmission electron microscopy. Silver nanoparticles with sizes ranging from a few nanometers to several tens of nanometers were observed in the titanium oxide matrix. The crystalline titanium oxide-silver nanoparticle composite powder decomposed the methylene blue dye upon visible light irradiation. The decomposition rate of the dye using the crystalline titanium oxide-silver nanoparticle composite powders was considerably faster than that in the case of the reference titanium oxide powder without silver nanoparticle. Thus, plasmon-induced charge separation from the silver nanoparticle to the conduction band of titanium oxide expected to occur, and holes on silver nanoparticles or induced active oxygen decomposed methylene blue in the solution or adsorbed on titanium oxide.