Rapid preparation of terbium-doped titanium dioxide nanoparticles and their enhanced photocatalytic performance

Abstract

Further applications of photocatalysis were limited by the high recombination probability of photo-induced electron–hole pairs in traditional titanium dioxide nanoparticles (TiO2 NPs). Herein, we modified them with rare earth metal via a facile sol–gel method, using tetrabutyl titanate as a precursor and terbium (III) nitrate hexahydrate as terbium (Tb) source. The resulting samples with different Tb doping amounts (from 0 to 2%) have been characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photo-electron spectroscopy and a scanning electron microscope. The photocatalytic performance of Tb-doped TiO2 was evaluated by the degradation of methylene blue. The effects of Tb doping amount and initial pH value of solution were investigated in detail. The composite with Tb doping amount of 1.0 wt% showed the highest photocatalytic performance. It exhibited approximately three times enhancement in photocatalytic activity with a reaction rate constant of 0.2314 h−1 when compared with that of commercial P25 (0.0827 h−1). In addition, it presented low toxicity on zebrafishes with 96 h-LC50 of 23.2 mg l−1, and has been proved to be reusable for at least four cycles without significant loss of photocatalytic activity. A probable photocatalytic mechanism of Tb-doped TiO2 was proposed according to the active species trapping experiments. The high photocatalytic performance, excellent reusability and low toxicity of Tb-doped TiO2 indicated that it is a promising candidate material in the future treatment of dye wastewater.

Impact of Tb4+ and morphology on the thermal evolution of Tb-doped TiO2 nanostructured hollow spheres and nanoparticles

“…In the case of the bixbyte structure, Tb 3+ oxidizes easily due to the presence of oxygen vacancies in the crystal lattice [26]. In Tbdoped anatase photocatalysts prepared by sol-gel from terbium (III) nitrate hexahydrate and tetrabutyl titanate and calcined at 500ºC for 4 h Tb 4+ and Tb 3+ were also detected by XPS [13]. Those catalysts are similar materials than those studied in this work and also prepared by sol-gel.…”

“…Furthermore, terbium is adequate for the fabrication of visible light emitting devices, because of its usually intense intra-4f transitions at wavelengths in the visible range 400-600 nm [10]. In previous studies, Tb-doped TiO2 thin films and bulk materials have been prepared but not hollow spheres [11][12][13].…”

Synthesis of nitrogen and terbium co-doped TiO2nanocrystals with enhanced photocatalytic activity for AO7 degradation under visible-light radiation

“…It is clearly observed that while N doping effectively narrowed the band gap of the undoped TiO 2 nanocrystals by 0.32 eV, further doping of the N-TiO 2 nanocrystals with Tb only slightly widened the band gap of the N-TiO 2 nanocrystals by 0.1 eV, which can be attributed to their smaller sizes compared with the N-TiO 2 nanocrystals. 30,31 This also implies that Tb resided mostly at the crystal boundary of TiO 2 nanocrystals, and did not have a significant impact on the band structure of the TiO 2 nanocrystals.…”

Influence of yttrium and niobium oxides modifiers on physicochemical and photocatalytic properties of titanium (IV) oxide

“…This approach was used in [38], where the titanium (IV) oxide modification by europium resulted in a significant improvement in photoactivity (degradation occurs under sunlight in natural conditions). Other researchers [39] found an increase in the dye degradation rate (at least 3 times) during the photocatalytic process of erbium-modified titanium (IV) oxide.…”