Synthesis of TiO2-Ag Core-Shell Nanostructures for Visible Range Photocatalysis

Magdalena Gajda-Rączka Institute of Optoelectronics, Military University of Technology, Warsaw, Poland Piotr Nyga Institute of Optoelectronics, Military University of Technology, Warsaw, Poland Bartłomiej Jankiewicz Institute of Optoelectronics, Military University of Technology, Warsaw, Poland

Nanoscale titanium dioxide (TiO2) is one of the most widely investigated oxide semiconductor materials in many fields, such as environmental cleanup, photocatalysis and photovoltaics, due to its excellent performances. However applications of TiO2 related to its optical properties are limited by the fact that its band gap energy corresponds to electromagnetic radiation in the UV region. Thus, one of the goals for improvement of the performance of TiO2 nanomaterials is to increase their optical activity by shifting the onset of the response from the UV to the visible region [1]. One of the approach to achieve this goal is to synthesize hybrid functional core-shell nanostructures based on the TiO2 and noble metals. Noble metals, like Ag or Au, deposited on the surface of TiO2 particles enhance the photocatalytic efficiency under visible light by acting as an electron trap, promoting interfacial charge transfer and therefore delaying recombination of the electron–hole pair [2].

In this work we present results of studies on fabrication and characterization of metal-dielectric hybrid nanostructures, composed of titania spheres coated with a semicontinuous layer of silver. TiO2 spheres were fabricated using sol-gel method [3]. The metallic shell was obtained by direct reduction of silver nitrate on the titania particles surface using glucose. Characterization of the morphology of fabricated structures was carried out by using SEM microscopy. Optical properties of fabricated structures were characterized using UV-Vis spectroscopy. The photocatalytic activity of the materials was studied by examining the degradation reaction of R6G.

Acknowledgements:

This work is funded by the National Science Centre under grant No. 2011/03/D/ST5/06038.

References:

[1] Chen X., Mao S.S. Chem. Rev. 2007, 107, 2891-2959.

[2] Pelaez M., Nolan N.T., Pillai S.C., Seery M.K., Falaras P., Kontos A.G., Dunlop P.S.M., Hamilton J.W.J., Byrne J.A., O’Shea K., Entezari M.H., Dionysiou D.D. Appl. Catal. B 2012, 125, 331– 349.

[3] Mine E., Hirose M., Nagao D., Kobayashi Y., Konno M. J. Colloid Interface Sci.- 2005, 291, 162–168.

bjankiewicz@wat.edu.pl









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