Nitrogen/Palladium-Codoped TiO2 for Efficient Visible Light Photocatalytic Dye Degradation

Elimination of toxic organic compounds from waste-water is currently one of the most important subjects in water pollution control. Eosin Yellow, an anionic xanthene fluorescent dye, known to be carcinogenic, originates mainly from textile industrial processes and is resistant to conventional chemical or biological water treatment methods. Photocatalysis using non metal/platinum group metal-codoped TiO2 may provide effective means of removing such dyes from contaminated water. In this study, nitrogen/palladium-codoped TiO2 photocatalysts were prepared by calcination of the hydrolysis product of titanium isopropoxide, Ti(OC3H7)(4), with aqueous ammonia. Samples were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), diffuse reflectance UV-vis spectrophotometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Anatase phase particles of size range 10-20 nm were confirmed by XRD, Raman, TEM, and SEM analysis. Codoping imparted a red shift in the absorption edges of the materials. Codoped TiO2 showed greater photocatalytic Eosin Yellow degradation efficiency compared to singly doped N-TiO2 or Pd-TiO2 under visible light irradiation. The highest initial reaction rate of 2.238 x 10(-2) min(-1) was observed for N/Pd-TiO2 (0.8% Pd). The results demonstrated that the N/Pd-codoped TiO2 (0.6% Pd) sample could completely degrade the dye in 3 h, while the commercial TiO2, (Degussa P25) showed the lowest dye degradation efficiency.