Effect of s-doping on the physico-chemical properties and the conductivity of titania nanostructures

Prof. German Telbiz, (Ukraine)

Video was recorded during the 6th International research and practice Conference "Nanotechnolgy and Nanomaterials" (NANO-2018)

Structural modification of TiO2 by non metal ion doped has gained a significant scientific interest and practical importance for the enhancement of TiO2 properties while the main aspects of the anion integration in the TiO2 structure are still debatable. For the explanation of the possible mechanism of integration of the doping element and genesis of nanocomposites, their properties were studied by a number of physical methods (XRD, XPS, FTIR, UV-VIS, TGA, TD MS, SEM, TEM, WAH etc). The XRD and Raman data of the hydrothermally sol-gel synthesized S-doped TiO2 nanostructures show that the expansion of lattice strain is possible with increasing dosage of H2SO4. It was shown that for sulfate ion during sol-gel synthesis can to the formation on the surface of anatase bidentate structures that regulate acidic properties of the surface of the composite. At an optimal concentration of the dopant, the composite structure has significant hydrophilicity, high density of interaction of OH groups on the surface that, stable at temperatures up to 350oC and enhanced, relative to other samples, electron, and proton conductivity. The calculated value the OH surface density of the S doped samples showed their growth compare with standard materials. Was found that the S-doped TiO2 materials catalysts successfully promote selective gas-phase oxidation of ethanol when illuminated with UV light. The rates of photocatalytic reaction are more than twice as high in the case of S-doped TiO2 compared with Degussa P25. The fact may be directly ascribed to the influence of the morphology, structure, OH-density in doped samples. Preliminary tests of proton conductivity (the direct injection of protons) that was carry out on the composite membrane, has highlighted the benefit of doped titania nanocomposites introduction on the conductivity in the temperature range up to 240° C, that maintained at (10-3-10 -5 S ), compared to the commercial Nafion membrane.The above may be a prerequisite for effective behavior composite polymer membrane in conditions close to the operating conditions of fuel cells.