Band gap and morphology engineering of TiO₂ by silica and fluorine co-doping for efficient ultraviolet and visible photocatalysis

Abstract

Silicon and fluorine co-doped anatase TiO 2 (Si-F-TiO 2 ) photocatalysts with enhanced photocatalytic activity were successfully prepared via a facile two-step synthetic method by using SiO 2 powders and (NH 4 ) 2 TiF 6 as the precursors. The obtained products were thoroughly characterized by various techniques, including scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), UV-visible diffuse reflectance spectroscopy and N 2 adsorption-desorption analysis. These characterizations reveal the effects of molar ratio of silica to titanium(R) and pH value on morphology, size and crystal structure of Si-F-TiO 2 samples. We find that the band gap of the catalyst can be engineered from 3.16 to 2.88 eV via altering the molar ratio of Si : Ti and pH value.Compared with un-doped or F-doped TiO 2 , co-doped Si-F-TiO 2 samples exhibited improved photocatalytic degradation toward different dye molecules under both ultraviolet and visible light illumination. With the aid of holes and radicals trapping experiments, we proposed the photocatalytic mechanism for the examined systems. Furthermore, first-principle calculations provide theoretic insights for the enhanced photocatalytic performance of codoped Si-F-TiO 2 photocatalyst.

Synthesis, characterization and visible light photocatalytic activity of Mg2+ and Zr4+ co-doped TiO2 nanomaterial for degradation of methylene blue

“…In this regard, a great effort has been made to develop TiO 2based photocatalysts sensitive to visible light for the purpose of efficient utilization of solar energy such as metal and non-metal ion doping, semiconductor coupling and dye sensitization to improve the photocatalytic activity of TiO 2 materials under visible light irradiation [8][9][10]. However, it must be noted that each of these methods has some drawbacks like limited surface area, less crystalline nature and low migration ability of the photo exited charge carriers under visible light [11,12].…”

Ultradispersed titanium dioxide nanoparticles embedded in a three-dimensional graphene aerogel for high performance sulfur cathodes

“…5e) can be predominantly tted into three distinct peaks. The peak at 530.4 eV corresponds to oxygen bound to Ti 4+ (Ti-O) in TiO 2 as well as the C]O bond in GA. 30,31 The other two peaks at 531.2 eV and 533.8 eV can be referred to the hydrated oxygen (OH-C) and epoxide (C-O-C), respectively. 32 As for GA-TiO 2 /S composites, the sulfur infusion has resulted in an extra characteristic peak at 532.1 eV, which can be assigned to oxygen bound to sulfur (O-S) (Fig.…”

“…First, graphene oxide (GO) was synthesized from natural graphite powder using a modied Hummers method. 30 Then, 85.3 mg Ti(SO 4 ) 2 and 2.4 mg glucose was dissolved in 50 mL GO aqueous solution (1.6 g L À1 ) under the magnetic stirring. Next, the mixture solution was transferred into a 100 mL Teonsealed autoclave and heated at 180 C for 12 h. The asprepared sample was washed with deionized water and ethanol several times, then freeze-dried for 24 h. Finally, the GA-TiO 2 composites were obtained aer annealing at 800 C for 2 h in Ar.…”

Construction of Ag 3 PO 4 /Ag 2 MoO 4 Z-scheme heterogeneous photocatalyst for the remediation of organic pollutants

“…Among the numerous photocatalysts, TiO2 has proven one of the best-per-forming materials, owing to its non-toxicity, low cost, relatively high chemical stability and strong oxidizing power [10][11][12][13][14][15]. However, because of its large band gap (3.0 eV for rutile and 3.2 eV for anatase), TiO2 can only be activated under ultraviolet light (which accounts for about 5% of solar light) [16][17][18]. The poor light-harvesting ability of TiO2 in the visible-light region makes it difficult to realize efficient solar-driven photocatalysis for energy and environmental applications.…”