The Effect of Iron and Niobium Co-Doping Ratio on the Photocatalytic Activity of Sol-Gel Derived Titanium Dioxide (original) (raw)

As metal co-dopants, Fe and Nb have been reported to improve the photoquantum efficiency of TiO 2 by simultaneously lowering the band gap energy and improving charge separation. In this study, the effects of varying the co-doping ratio of Fe and Nb on the physicochemical properties and photocatalytic activity of TiO 2 photocatalysts prepared using a temperature-controlled sol-gel method were investigated. The combined co-dopant molar loading was held constant (0.25%) while the co-doping ratio of Fe and Nb was varied. The physicochemical properties of TiO 2 were monitored by characterizing the photocatalysts in terms of crystallite phase (XRD), band gap energy (UV-Vis Spectrophotometry), specific surface area (3point BET), and surface morphology/composition (SEM-EDX). Measurement of the band gap energy confirmed the band gap-lowering effect of Fe, but the lower band gap energy of Nb-TiO 2 compared to pure TiO 2 indicated that Nb also exhibits a band-gap lowering effect. After 6 hours of photocatalytic testing, 1:2 Fe:Nb-TiO 2 displayed the highest photocatalytic activity among the photocatalysts with 64.78% decolorization of the lignin model pollutant under UV illumination and 38.02% under visible light illumination. All co-doped photocatalysts exhibited higher photocatalytic activity compared to pure TiO 2 under visible light illumination, confirming the cooperative effects of Fe and Nb towards improving the photocatalytic activity of TiO 2 .