Enhanced dielectric properties of N-doped TiO2 and its photocatalytic activity in sunlight

In the present work TiO₂ was synthesized by using TiCl₃ and nitrilotriacetic acid and HNO₃ (TC). Synthesized TiO₂ was found to be with smaller particle size with high surface area. Synthesized TiO₂ shows formation of mixed phases and is confirmed from the XRD analysis. Dielectric properties of the synthesized TiO₂ has been investigated for large domain signal frequencies. Dielectric constant of TC increases than that of DP-25 and shows high tangent loss. High (Ac) Alternating current conductivity was obtained for TC than the Degussa commercial TiO₂(DP-25). Point of zero charge (PZC)measurements were carried out to find the charge on the surface of the catalyst. The nitrogen doping in the sample TC was confirmed from the XPS spectrum. Photocatalytic activity of the synthesized TiO₂ was studied by selecting methylene blue dye as common pollutant in sunlight. The high photocatalytic activity was shown by catalyst TC with N doping and anatase–rutile mixed phase. N doping in the sample has improved the light response and further facilitate the absorption of photons to produce electron–hole pairs under sunlight reaction. Nitrogen doping and presence of mixed phase inhibit the recombination of photoinduced carriers and thus increase the quntum efficiency of TC photocatalyst.