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

• Published in: Applied surface science Vol. 264; pp. 139 - 147
• Main Authors: Bagwasi, Segomotso, Niu, Yuxiao, Nasir, Muhammad, Tian, Baozhu, Zhang, Jinlong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2013; Elsevier
• Subjects: 2,4-Dichlorophenol; Bismuth modification; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Photocatalyst; Physics; Visible light, Degradation; 2,4-Dichlorophenol; Photocatalyst; Bismuth modification; Visible light, Degradation; Inorganic compounds; Transition element compounds; Bismuth; Doped materials; Nitrogen; Titanium oxide
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2012.09.145

► Bi/N–TiO2 nanoparticles were prepared by hydrothermal and impregnation method. ► Bi20TiO32/N–TiO2 composites were formed from 7mol% Bi loading in relation to Ti. ► Bi4+ was doped in the sub-surface while Bi20TiO32 was dispersed on the surface. ► Bi/N–TiO2 degraded 2,4-DCP under visible light effectively. ► Bi species enhanced visible light harvesting, e−/h+ separation and mobility. Bismuth modified nitrogen doped TiO2 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), N2 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 TiO2 nanoparticles with varied amounts of Bi content. XRD analysis results reveal that Bi exists as rare metastable Bi20TiO32 which started to surface at Bi loading content of 7mol% in relation to Ti ions. All Bi modified N–TiO2 samples exhibited higher photocatalytic activity toward degradation of 2,4-DCP over N–TiO2 under visible light irradiation. The sample with 10% composition of the Bi20TiO32 exhibited the highest activity. The superior photocatalytic performance of 10%Bi/N–TiO2 is attributed to high visible light absorption as well as effective charge carrier separation. Therefore, the role of Bi species in the N–TiO2 is improvement of visible light harvesting and facilitation of charge carrier separation hence alleviating electron–hole recombination.