The study of visible light active bismuth modified nitrogen doped titanium dioxide photocatlysts: Role of bismuth

摘要

Bismuth modified nitrogen doped TiO_2 nanoparticles have been successfully prepared by two steps synthesis route which includes hydrothermal and impregnation hydrolysis method. Samples were characterized using X-ray diffraction (XRD), N_2 physical adsorption, Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), Fourier Transmission Infrared (FTIR), Raman, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PLS) technologies. The preparatory method afforded the production of well crystallized spherical Bi modified N-doped TiO_2 nanoparticles with varied amounts of Bi content. XRD analysis results reveal that Bi exists as rare metastable Bi_(20)TiO_(32) which started to surface at Bi loading content of 7 mol% in relation to Ti ions. All Bi modified N-TiO_2 samples exhibited higher photocatalytic activity toward degradation of 2,4-DCP over N-TiO_2 under visible light irradiation. The sample with 10% composition of the Bi_(20)TiO_(32) exhibited the highest activity. The superior photocatalytic performance of 10%Bi/N-TiO_2 is attributed to high visible light absorption as well as effective charge carrier separation. Therefore, the role of Bi species in the N-TiO_2 is improvement of visible light harvesting and facilitation of charge carrier separation hence alleviating electron-hole recombination.