Nanocomposites and nanomaterials

Visible light photocatalytic properties of nano-sized tin dioxide doped with iron.
M. Samsonenko1, S. Khalameida1, V. Starchevskyy2, L. Kotynska1
1 Institute for Sorption and Problems of Endoecology, NAS of Ukraine. 
13, Naumova st., Kyiv 03164, Ukraine.
E-mail: mashuna.08@gmail.com
2 Institute of Chemistry and Chemical Technology, L’viv National Polytechnic University, 12 S. Bandera Str., 79013 L’viv, Ukraine.

The application of nano-sized oxides for photocatalytic degradation is a promising method of wastewater treatment. The use of visible light simplifies and reduces the cost of this process. One of the promising photocatalysts is tin dioxide. To increase the efficiency of its use in photocatalytic processes under the action of visible light, can use its doping with transition metals. It is known that the use of iron as a doped additive to titanium dioxide can increase photocatalytic activity including through inhibition of electron/hole pairs recombination. For SnO2, this approach has been little studied. Thus, the aim of this work is to study the effect of sonochemical doping on the photocatalytic properties of iron-doped tin dioxide.
Initial heterogeneous precipitation gel SnO2 was subjected to doping with 5% Fe(III) by sonochemical treatment of wet gel and next thermal treatments at 300°C. Doping and thermal treatment of samples leads to more perfect crystalline structure and an increase in the size of the crystallites. Iron-doped samples of tin dioxide are characterized by high values of specific surface area (137 and 205 m2/g), and mesoporous structure with pores with a diameter of about 4.7 nm. Changes in the electronic structure are manifested in an increase of absorption of visible light 3-4 times and decrease in the band gap Eg from 4.2 eV to 2.9 еV for initial and doped samples, respectively. These transformations of physico-chemical parameters contribute to the increase in photocatalytic activity of iron-doped tin dioxide in processes of the dyes degradation under visible light. The rate constant of rhodamine B and safranin T degradation for Fe-doped SnO2 is increasing 2-3 times. In addition, in contrast to inactive initial tin dioxide, doped samples exhibit photocatalytic activity during the degradation of 4-chlorophenol under visible irradiation.

This work was supported by the framework of the research project of young scientists from the National Academy of Sciences of Ukraine «Alternative methods of doping SnO2-based materials to purification of the water environment from pollutants», (contract no :75-09/03-2022).