Preparation of photocatalytic Au-Ag2Te nanomaterials.

A facile approach has been developed for the preparation of various morphologies of Au-Ag(2)Te nanomaterials (NMs) that exhibit strong photocatalytic activity. Te NMs (nanowires, nanopencils, and nanorice) were prepared from TeO(2) in the presence of various concentrations (16, 8, and 4 M) of a reducing agent (N(2)H(4)) at different temperatures (25 and 60 °C). These three Te NMs were then used to prepare Au-Ag(2)Te NMs by spontaneous redox reactions with Au(3+) and Ag(+) ions sequentially. The Au-Ag(2)Te nanopencils exhibit the highest activity toward degradation of methylene blue and formation of active hydroxyl radicals on solar irradiation, mainly because they absorb light in the visible region most strongly. All three differently shaped Au-Ag(2)Te NMs (10 μg mL(-1)) provide a death rate of Escherichia coli greater than 80% within 60 min, which is higher than that of 51% for commercial TiO(2) nanoparticles (100 μg mL(-1)). Under light irradiation, the Au NPs in Au-Ag(2)Te NMs enhance the overall photo-oxidation ability of Ag(2)Te NMs through faster charge separation because of good contact between Ag(2)Te and Au segments. With high antibacterial activity and low toxicity toward normal cells, the Au-Ag(2)Te NMs hold great potential for use as efficient antibacterial agents.