Investigation of photocatalytic activities of nanostructured nitrogen dopedTiO۲ thin films under visible light prepared via sol-gel method on type ۳۰۴stainless steel

Nowadays photocatalyst materials especially TiO۲ are widely used in different fields andindustries such as self-cleaning surfaces, water purification, solar cells and biomaterials. A greatdrawback about TiO۲ as a practical photocatalyst material is its wide band gap energy. TiO۲ canonly cause photocatalytic reactions under UV light; therefore its indoor applications as aphotocatalyst material are restricted due to the lack of UV light in such places. In this research,nanostructured nitrogen doped TiO۲ films were prepared on type ۳۰۴ stainless steel by sol-gelmethod using an airbrush to apply the sol on the surface of the steel, then samples were calcined atvarious temperatures between ۴۰۰°C and ۶۰۰°C. Grazing incidence XRD and conventional XRDwere used to determine the phase composition of the samples, the thickness of films were measuredby ellipsometry, also UV–Vis spectra analyses (in diffuse reflectance mode) was utilized to estimatetheir band gap energy. Results showed that films thickness was ۱۵۰nm and due to doping of nitrogeninto TiO۲ structure, its band gap energy reduced to ۲.۸۵ eV which was completely shifted towardvisible region. Measurement of methylene blue degradation under visible light was used toinvestigate the photocatalytic activities of thin films. The sample that was calcined at ۵۰۰°C showedthe best photocatalytic performance and it degraded ۲۲% of methylene blue after ۲ hours undervisible light

Keywords:

Visible light activated TiO۲ , Nanostructured thin film , Photocatalysis , Sol spraying