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Sol-gel synthesis and properties of nanocomposites in the Ag/TiO2/ZnO system

A. SHALABY1,2,* , A. BACHVAROVA-NEDELCHEVA3, R. IORDANOVA3, Y. DIMITRIEV2, A. STOYANOVAd4, H. HITKOVA4, N. IVANOVA4, M. SREDKOVA4

Affiliation

  1. STCE – Science and Technology Center of Excellence, Cairo-Egypt
  2. University of Chemical Technology and Metallurgy, 8 Kl. Ohridski blvd., 1756 Sofia, Bulgaria
  3. Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, G. Bonchev str., bld. 11, 1113 Sofia, Bulgaria,
  4. Medical University, 5800 Pleven, Bulgaria

Abstract

Composite powders with initial components Ag, TiO2 and ZnO were prepared by sol-gel processing containing titanium ethoxide, silver nitrate and zinc acetate as precursors in an Ag/Ti/Zn atomic ratio of 1:2:3. The as-obtained gels were stepwise calcinated up to 6000C. The phase and structural transformations at every step of the heat treatment were followed by X-ray phase analysis. The amorphous phase which is dominant up to 300ºC decreases gradually with increasing the temperature, while elementary silver, ZnO and cubic ZnTiO3 coexist simultaneously in a nanocomposite at 500ºC. At 6000C the crystallinity of the sample increased and the amount of amorphous phase is small enough to be negligible. The average particle size of ZnTiO3 increases from 6 to 10 nm, of elementary silver – 25 nm and ZnO – 24 nm in the range 500-6000C. The obtained Ag/ZnO/ZnTiO3 composite showed photocatalytic activity toward Malachite Green (MG) under ultraviolet and visible light irradiation. The antibacterial activity was examined in the dark and under UV-light using as a test-microorganism Escherichia coli ATCC 25922. The obtained nanocomposite possesses а powerful bactericidal effect and can completely kill E. coli bacteria after 30 minutes. A simple scheme for performance of a complex composite containing three active phases was suggested..

Keywords

Sol-gel, Ag/ ZnO/ZnTiO3 composite, Photocatalyst, Antibacterial properties.

Submitted at: June 25, 2014
Accepted at: Jan. 21, 2015

Citation

A. SHALABY, A. BACHVAROVA-NEDELCHEVA, R. IORDANOVA, Y. DIMITRIEV, A. STOYANOVAd, H. HITKOVA, N. IVANOVA, M. SREDKOVA, Sol-gel synthesis and properties of nanocomposites in the Ag/TiO2/ZnO system, Journal of Optoelectronics and Advanced Materials Vol. 17, Iss. 1-2, pp. 248-256 (2015)