Synthesis of TiO2 core/RuO2 shell particles using multistep ultrasonic spray pyrolysis

Spherical submicron-particles with TiO2 core-RuO2 shell structure have been synthesized by employing sequential ultrasonic spray pyrolysis. The particles have been investigated by X-ray powder diffraction, scanning electron microscopy and different transmission electron microscopy techniques. The quality of the core-shell structure of the particles has been confirmed by comparison of the experimental data with those generated on the basis of a hard sphere core-shell model. It has been found that the mixing of the Ru-containing aerosol with the TiO2 particle stream has a significant impact on the core-shell formation. The method introduced in this study can probably be applied for preparation of core-shell and core-multishell materials that are difficult to synthesize in a single step spray pyrolysis process. (C) 2013 Elsevier Ltd. All rights reserved.