Photocatalytic activity of TiO2-capped ZnO nanoparticles

• Published in: Journal of materials science. Materials in electronics 2012-02, Vol.23 (2), p.361-369
• Main Authors: Lak, Aidin, Simchi, Abdolreza, Nemati, Ziarat Ali
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Electronics; Materials Science; Nanoparticles; Optical and Electronic Materials; Shells; Sol gel process; Titanium; Titanium dioxide; Zinc oxide
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-011-0396-8

Using a combined hydrothermal and sol–gel route , TiO 2 - capped ZnO nanoparticles with an average size of 60 nm were prepared. The titania shell was amorphous with a thickness of ~10 nm. Formation of Zn 2 TiO 4 phase at higher calcination temperature was noticed. Effects of Ti/Zn molar ratio and coating time on the thickness of TiO 2 shell and the photoactivity of the particles for decolorization of Methylene Blue (MB) under UV lamp irradiation (3 mW/cm 2 ) were investigated. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, fourier-transform infrared spectrometry (FTIR), diffuse reflectance spectroscopy (DLS), and atomic absorption spectroscopy. Analysis of the photoactivity results according to Langmuir–Hinshelwood model revealed a two-step decolorization process with a high kinetics rate at the early stage followed by a slower step. The capped nanoparticles synthesized under specific conditions exhibited higher photodecolorization yield and faster kinetics in comparison to the uncoated ZnO and P25-Degussa TiO 2 nanoparticles.