Preparation and Characterization of Ag@TiO2 Core‐Shell Nanoparticles in Water‐in‐Oil Emulsions

We report a simple route for the effective synthesis of Ag@TiO2 nanoparticles in water‐in‐oil (w/o) emulsions and provide detailed characterization of the materials with TEM, TG‐DTA, IR, XRD, and SPS measurements. Such core‐shell hybrid nanoparticles can be fabricated in two simple steps: the formation of the silver core by the reduction of a Tollens reagent with glucose in the water phase, and the hydrolysis of Ti(OC4H9)4 at the water/oil interface for the formation of the amorphous TiO2 shell. The procedure led to the formation of nanocomposites with a crystalline core in a size range from 5 to 15 nm in diameter and an amorphous shell of 6–10 nm thickness in a typical synthesis. The shell was converted to crystalline oxide upon thermal treatment. Surface photovoltaic spectroscopy (SPS) measurements indicate that the materials have potential for application in photoinduced electron storage and photocatalysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)