One step activation of WOx/TiO2 nanocomposites with enhanced photocatalytic activity

Sajjad, Ahmed Khan Leghari; Shamaila, S.; Tian, Baozhu; Chen, Feng; Zhang, Jinlong

doi:10.1016/j.apcatb.2009.06.005

Cited by 216 publications

(107 citation statements)

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“…However, sample 5%WTS0.7 shows an additional broad and weak absorption (inset of Fig. 5A) in ranging from 400 to 450 nm that is ascribed to an O −2 -W +6 charge transfer transition [14]. Corresponding band gap energies (E g ) of above samples were calculated by an empirical equation ˛h = A(hv-Eg) n/2 as 2.8 eV, 3.11 eV, and 3.04 eV for 8%WS, TS0.7, and 5%WTS0.7, respectively, as seen in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Besides, the incorporation of WO 3 into composites is able to increase the surface acidity since WO 3 is much more acidic than TiO 2 [9,[13][14][15], and the increase of surface acidity induces the high affinity of composites to those species with unpaired electrons, such as dissolved O 2 , H 2 O, OH − and organic contaminants, benefitting the generation of • O 2 − and • OH radicals and further decomposition of contaminants.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Chang

Wang

Luo

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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h i g h l i g h t s• A series of tungsten-titaniumcocontained SBA15 composites were fabricated by a simple synthetic route.• These samples showed enhanced catalytic performance in comparison to those comprising bare tungsten or titanium component.• The enhancement of photocatalytic behavior under visible-light irradiation was discussed. t r a c tA facile and one-step hydrothermal procedure was adopted to fabricate a series of W-Ti-SBA15 composites (WTS). These as-prepared composites were systematically characterized by a collection of analytic and spectroscopic techniques. It was found that dual phases of titanium and tungsten species coexisted in mesoporous structures of p6 mm hexagonal symmetry. In addition, these composites were visible-light responsive and exhibited enhanced photocatalytic capability toward degradation of Rhodamine B (RhB) and 2,4-dichlorophenol (2,4-DCP) upon visible-light irradiation in comparison to samples containing single component of titanium or tungsten species. Specifically, the best candidate, sample 8%WTS0.7, had the largest apparent reaction rate constant that was nearly 1.2, 2.1, 2.2, and 5.7 times as high as those of 8%WS, TS0.7, WO 3 /TiO 2 , and N-TiO 2 , respectively. The enhancement of photocatalytic performance was mainly attributed to the well-matched band structures of both components and strengthened visiblelight adsorption ability, originating from the combination of titania with highly acidic WO 3 in SBA15 matrix with large specific surface areas. Active radical species were detected by trapping experiments and a possible photocatalytic mechanism was thus proposed.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Chang

Wang

Luo

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…Generally, weaker PL response leads to slow recombination rate thereby increasing the life-time of photogenerated charge carries and hence better photocatalytic activity. 47 Fig . 6 shows the PL spectra at excitation wavelength of 320 nm for pure and RE-doped ZnO nanoparticles.…”

Section: Photoluminescence (Pl) Studymentioning

confidence: 99%

Comparative photocatalytic activity of sol–gel derived rare earth metal (La, Nd, Sm and Dy)-doped ZnO photocatalysts for degradation of dyes

et al. 2018

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Rare earth metal doping into semiconductor oxides is considered to be an effective approach to enhance photocatalytic activity due to its ability to retard the electron-hole pair recombination upon excitation.Herein, we report the synthesis of different rare earth metal (La, Nd, Sm and Dy)-doped ZnO nanoparticles using a facile sol-gel route followed by evaluation of their photocatalytic activity by studying the degradation of methylene blue (MB) and Rhodamine B (RhB) under UV-light irradiation.Different standard analytical techniques were employed to investigate the microscopic structure and physiochemical properties of the prepared samples. The formation of the hexagonal wurtzite structure of ZnO was established by XRD and TEM analyses. In addition, the incorporation of rare earth metal into ZnO is confirmed by the shift of XRD planes towards lower theta values. All metal doped ZnO showed improved photocatalytic activity toward the degradation of MB, of which, Nd-doped ZnO showed the best activity with 98% degradation efficiency. In addition, mineralization of the dye was also observed, indicating 68% TOC removal in 180 min with Nd-doped ZnO nanoparticles. The influence of different operational parameters on the photodegradation of MB was also investigated and discussed in detail.Additionally, a possible photocatalytic mechanism for degradation of MB over Nd-doped ZnO nanoparticles has been proposed and involvement of hydroxyl radicals as reactive species is elucidated by radical trapping experiments.

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“…The substitution of Ti 4+ instead of W 6+ , proposed from XPS result, is agreement with the discussion of Raman Spectrum. 56,58 Figure 8 shows cyclic voltammograms for each of the four thin films at their first, 500 th and 1000 th cycles in 1 M LiClO 4 dissolved in propylene carbonate at a sweep rate of 50 mV/s. The capacity of the electrochromic process can be ascertained from the total charge inserted into the films during each scan (i.e.…”

Section: 47mentioning

confidence: 99%

Electrochromic Enhancement of WO₃-TiO₂Composite Films Produced by Electrochemical Anodization

Gui

Blackwood

2014

J. Electrochem. Soc.

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An enhancement of the electrochromic properties of WO 3 thin films by the incorporation of TiO 2 is presented. The composite films are obtained by anodizing co-sputtered tungsten / titanium on conductive glass substrates in 1 M H 2 SO 4 solution containing 0.3 wt% NaF. As the titanium content is increased from 0 to 15 at.% a morphology evolution occurs, from nano-porous to nano-flakes and finally to nano-blocks interweaved with nano-pores. The nano-flakes, obtained at 10 at% Ti, proved to be the most conducive structure for the insertion and removal of Li + ions such that this composition exhibits transmittance regulation abilities of 58.5%, 72% and 77.7% at 550 nm, 632.8 nm and 800 nm respectively, which are more than a 25% improvement at all wavelengths over a pure WO 3 film formed in the same way. The WO 3 /TiO 2 film with addition of 10 at.% Ti also has faster coloration/bleaching times, especially in the critical near infrared region with values of 10 s / 64 s at 800 nm compared with 32 s / 90 s of a pure WO 3 thin film, as well as improved stability losing less than 5% of its capacity after 1000 switching cycles. and electrodeposition. 11,12 However, the electrochemical anodization method adopted in this work provides a simple and economic way of synthesizing targeted morphologies such as nanoporous or nanotube structures. Unfortunately there are still drawbacks when compared to vacuum deposited films, for instance the electrochemically prepared WO 3 has poorer reversibility and stability as well as a shorter optical modulation range. This has led to interest in mixed metal oxide composite systems to compensate for these eficiencies. [13][14][15][16][17][18][19] To date, there are many reports on the doping or mixing other oxides with WO 3 to improve its electrochromic properties, with oxides of barium, 20 cobalt, 21 nickel, 22 molybdenum 23 and most successfully titanium.24 Even a small quantity of the guest oxide has a profound effect on the host's optical properties. Hashimoto and Matsuoka first reported in 1991 that an amorphous WO 3 -TiO 2 film, produced by electron beam deposition method, exhibits a longer life-time than a pure tungsten oxide film. 24 Subsequently, in 1993, Gottsche et al. 25 compared the electrochromic properties of mixed WO 3 -TiO 2 thin films fabricated by sputtering and sol-gel techniques. These authors point out that the addition of TiO 2 with molar percentages ranging from 10% to 15% reduced the crystallinity of WO 3 host and led to significant structural changes. Later, Wang and Hu successfully composed a TiO 2 -doped WO 3 film by spin coating and found that the Ti-addition stabilized the peroxotungstic acid in the spin coating solutions. 26 In 2005, Patil et al. 27 prepared WO 3 -TiO 2 films via a spray pyrolysis method and discussed the improved electrochromic reversibility and coloration efficiency.However, in these earlier works the coloration efficiency has not improved significantly to the level where it can be used in a practical smart window. Indeed, in some cases cert...

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One step activation of WOx/TiO2 nanocomposites with enhanced photocatalytic activity

Cited by 216 publications

References 70 publications

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Comparative photocatalytic activity of sol–gel derived rare earth metal (La, Nd, Sm and Dy)-doped ZnO photocatalysts for degradation of dyes

Electrochromic Enhancement of WO₃-TiO₂Composite Films Produced by Electrochemical Anodization

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One step activation of WOx/TiO2 nanocomposites with enhanced photocatalytic activity

Cited by 216 publications

References 70 publications

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Comparative photocatalytic activity of sol–gel derived rare earth metal (La, Nd, Sm and Dy)-doped ZnO photocatalysts for degradation of dyes

Electrochromic Enhancement of WO3-TiO2Composite Films Produced by Electrochemical Anodization

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Electrochromic Enhancement of WO₃-TiO₂Composite Films Produced by Electrochemical Anodization