Preparation of Porous F-WO3/TiO2Films with Visible-Light Photocatalytic Activity by Microarc Oxidation

Yeh, Chung-Wei; Wu, Kee-Rong; Hung, Chung-Hsuang; Chang, Hui S.; Hsu, Chuan‐Jen

doi:10.1155/2012/285129

Cited by 10 publications

(2 citation statements)

References 53 publications

(135 reference statements)

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“…Photoactive WO 3 films have been prepared through various methods such as hydrothermal [10,11] or sol-gel synthesis [12], magnetron sputtering [13], spray/aerosol pyrolysis [14,15], as well as electrochemically on the cathode [16][17][18] or anode [19,20]. A modification of anodic synthesis is plasma electrolytic oxidation (PEO), which has been used to grow transition metal oxide coatings and heterostructures [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Synthesis of a WO3/MoSx Heterostructured Bifunctional Catalyst for Efficient Overall Water Splitting

et al. 2023

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Photo-/electrochemical water splitting can be a suitable method to produce “green” hydrogen and oxygen by utilizing renewable energy or even direct sunlight. In order to carry out photoelectrochemical (PEC) water splitting, a photoanode based on transition metal oxides, which absorbs photons and produces photoexcited electron–hole pairs, is needed. The positively charged holes can then participate in the water oxidation reaction. Meanwhile, a cathodic hydrogen evolution reaction (HER) can occur more efficiently with electrocatalytic materials that enhance the adsorption of H+, such as MoS2. In this study, it was shown that WO3/MoSx heterostructured materials can be synthesized by an electrochemical method called plasma electrolytic oxidation (PEO). During this process, many micro-breakdowns of the oxide layer occur, causing ionization of the oxide and electrolyte. The ionized mixture then cools and solidifies, resulting in crystalline WO3 with incorporated MoSx. The surface and cross-sectional morphology were characterized by SEM-FIB, and the coatings could reach up to 3.48 μm thickness. Inclusion of MoSx was confirmed by EDX as well as XPS. Synthesis conditions were found to have an influence on the band gap, with the lowest value being 2.38 eV. Scanning electrochemical microscopy was used to map the local HER activity and correlate the activity hotspots to MoSx’s content and surface topography. The bifunctional catalyst based on a WO3/MoSx heterostructure was evaluated for PEC and HER water-splitting activities. As a photoanode, it could reach up to 6% photon conversion efficiency. For HER in acidic media, a Tafel slope of 42.6 mV·dec−1 can be reached.

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Section: Introductionmentioning

confidence: 99%

Electrochemical Synthesis of a WO3/MoSx Heterostructured Bifunctional Catalyst for Efficient Overall Water Splitting

et al. 2023

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“…Fluorine (F) was believed to be a promising dopant to enhance photocatalytic activity of TiO 2 and non-TiO 2 photocatalysts due to its ability in reducing the recombination rate of photogenerated electron-hole pairs, creating oxygen va-cancies, and increasing effective electron mobility 16,17) . The in uence of F on the photocatalytic activity of ZWO was reported by Huang et al 3) An enhanced photocatalytic activity was ascribed to accelerate the transfer-rate of photogenerated electrons to the photocatalyst surface, which resulted in a large number of electrons and holes participating in the photocatalytic process.…”

Section: Introductionmentioning

confidence: 99%

Influence of Fluorine on Structure, Morphology, Optical and Photocatalytic Properties of ZnWO4 Nanostructures

et al. 2017

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We report on the synthesis of Fluorine (F) doped-ZnWO 4 photocatalysts and the in uence of F-doping on their structure, morphology, optical and photocatalytic properties. A two-step process was used to produce F-doped ZnWO 4 photocatalysts. The quality of synthesized materials was characterized using different analytical methods, such as X-ray diffraction analysis, eld emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectra (FTIR), as well as photoluminescence (PL) measurement. It was found that the photocatalyst morphology and band gap energy strongly depend on the F-doping concentration. The band gap energy of the photocatalysts decreased when increasing F-doping concentration, and reached a lowest value at a concentration of 4 mol%, and then increased thereafter. At 4 mol% of F-doping, nanowires were formed with approximately 1 μm in length and 50 nm in diameter. On the contrary, others F-doped ZnWO 4 samples were obtained in the shape of nanorods or a mixture of nanorods and granular particles. Moreover, it was demonstrated that F-doped ZnWO 4 enhanced photocatalytic activity by a factor of three, as compared to that of un-doped ZnWO 4. This enhancement can be explained by the nanowire shape of synthesized F-doped ZnWO 4 , its narrow band gap energy and the small recombination rate of photogenerated electron-hole pairs, which was indirectly proved by PL spectra.

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Photocatalytic behaviour of WO3/TiO2-N for diclofenac degradation using simulated solar radiation as an activation source

Cordero-García

Palomino

Hinojosa‐Reyes

et al. 2016

Environ Sci Pollut Res

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In this study, the photocatalytic removal of an emerging contaminant, diclofenac (DCF) sodium, was performed using the nitrogen-doped WO/TiO-coupled oxide catalyst (WO/TiO-N). The catalyst synthesis was accomplished by a sol-gel method using tetrabutyl orthotitanate (CHOTi), ammonium p-tungstate [(NH)HWO·4HO] and ammonium nitrate (NHNO) as the nitrogen source. For comparison, TiO and WO/TiO were also prepared under similar conditions. Analysis by X-ray diffraction (XRD), N adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-Vis spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS) were conducted to characterize the synthesized materials. The photocatalytic efficiency of the semiconductors was determined in a batch reactor irradiated with simulated solar light. Residual and mineralized DCF were quantified by high-performance liquid chromatography, total organic carbon analysis and ion exchange chromatography. The results indicated that the tungsten atoms were dispersed on the surface of TiO as WO. The partial substitution of oxygen by nitrogen atoms into the lattice of TiO was an important factor to improve the photocatalytic efficiency of WO/TiO. Therefore, the best photocatalytic activity was obtained with the WO/TiO-N catalyst, reaching 100% DCF transformation at 250 kJ m and complete mineralization at 400 kJ m of solar-accumulated energy.

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Preparation of Porous F-WO₃/TiO₂Films with Visible-Light Photocatalytic Activity by Microarc Oxidation

Cited by 10 publications

References 53 publications

Electrochemical Synthesis of a WO3/MoSx Heterostructured Bifunctional Catalyst for Efficient Overall Water Splitting

Electrochemical Synthesis of a WO3/MoSx Heterostructured Bifunctional Catalyst for Efficient Overall Water Splitting

Influence of Fluorine on Structure, Morphology, Optical and Photocatalytic Properties of ZnWO<sub>4</sub> Nanostructures

Photocatalytic behaviour of WO3/TiO2-N for diclofenac degradation using simulated solar radiation as an activation source

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