Nazarkovsky M. Synthesis and properties of nanocomposites based on silica-titania doped by metal oxides

Dissertation is devoted to establishing the impact of doping oxides (CuO, SnO2 or NiO) upon (i) phase composition, (ii) morphology of silica-titania composites, (iii) charge and (iv) structure of their surface, (v) electronic structure and (vi) photocatalytic properties in the course of photooxidation of anthropogenic organic contaminants (caffeine, bisphenol А). Dopants have been shown to provoke non-linear changes in the properties of synthesized silica-titania composites. Specifically, such changes take place in the morphology, phase composition and value of the surface charge. Generally increased catalytic activity of the CuO-doped materials during the photoconversion of caffeine is in inverse relation to the concentration of the dopant - a sample at СCuO = 1 wt.% is more active than Р25 (Evonik) in five times. But increasing of NiO concentration generally enhances the effectiveness of silica-titania photocatalysts - the most active sample (at СNiO = 10 wt.%) has been shown to be more than 3 times active compared to P25. Photocatalytic properties of SiO2/TiO2/SnO2 materials are in non-linear relation to SnO2 content. The most active samples of both calcined and non-calcined analogues at СSnO2 = 6 wt. % are 3 and 2,4 times active than P25 respectively by the photodestruction of bisphenol A. It has been established that the properties of silica-ferrite composites covered with ТіО2 are linearly and predictably dependent on of their quantitative and qualitative composition. Particularly, decrease in the Vp and SBET is in direct proportion to the concentrations of both ferrite and titania phases. The content of Co2+ ions in octahedral surrounding in spinel-like CoFe2O4 gets depressed by the growth of TiO2 concentration.