Improved Photocatalytic Activity of TiO<sub>2</sub> on the Addition of CuWO<sub>4</sub>

Xiong, Xianqiang; Chen, Haihang; Xu, Yiming

doi:10.1021/jp510974f

Cited by 29 publications

(20 citation statements)

References 39 publications

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“…The anatase polymorph (tetragonal, a=b=3.785 Å, c=9.54 Å) is widely reported as the most photoactive phase of titania [14,15]. However, anatase TiO 2 has a wide energy band gap (3.2 eV) which results in a high electron-hole recombination rate and absorbance in only the UV light region [5,16,17]. Additionally, anatase is metastable and irreversibly transforms into the thermodynamically stable rutile phase (a=b=4.593 Å, c=2.959 Å) from 600°C-700°C [18,19].…”

Section: Introductionmentioning

confidence: 99%

Modification of TiO₂ with hBN: high temperature anatase phase stabilisation and photocatalytic degradation of 1,4-dioxane

Byrne¹,

Rhatigan²,

Hermosilla³

et al. 2019

J. Phys. Mater.

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This paper examines the modification of anatase TiO 2 with hexagonal boron nitride (hBN) and the impact this coupling has on the temperature of the anatase to rutile phase transition and photocatalytic activity. All samples were 100% anatase when calcined up to 500°C. At 600°C, all BN-modified samples contain mixed rutile and anatase phases, with 8% and 16% BN-TiO 2 showing the highest anatase contents of 64.4% and 65.5% respectively. The control sample converted fully to rutile at 600°C while the BN modified sample converted to rutile only at 650°C. In addition to TiO 2 phase composition, XRD also showed the presence of bulk boron nitride peaks, with the peak at 26°i ndicating the graphite-like hBN structure. Density functional theory calculations of hBN-rings adsorbed at the anatase (101) surface show strong binding at the interface; new interfacial bonds are formed with key interfacial features being formation of B-O-Ti and N-Ti bonds. Models of extended hBN sheets at the anatase (101) surface show that formation of B-O and N-Ti bonds along the edge of the hBN sheet anchor it to the anatase surface. 16% BN-TiO 2 at 500°C showed a significant increase in the photocatalytic degradation of 1,4-dioxane when compared with pure anatase TiO 2 at 500°C. This arises from the effect of hBN on anatase. The computed density of states (DOS) plots show that interfacing anatase with BN results in a red shift in the TiO 2 energy gap; N-p states extend the valence band maximum (VBM) to higher energies. This facilitates transitions from high lying N-p states to the Ti-d conduction band. A simple photoexcited state model shows separation of electrons and holes onto TiO 2 and BN, respectively, which promotes the photocatalytic activity.

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Section: Introductionmentioning

confidence: 99%

Modification of TiO₂ with hBN: high temperature anatase phase stabilisation and photocatalytic degradation of 1,4-dioxane

Byrne¹,

Rhatigan²,

Hermosilla³

et al. 2019

J. Phys. Mater.

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“…For applications involving the degradation of organic pollutants in water, CuWO 4 has been used as a catalytic material supported as a film or dispersed in suspension in the reaction medium [14,15]. Garcia-Perez et al [16] investigated the photoactivity of a suspension of several tungstates, used for 4-chlorophenol and methanol degradation under visible light irradiation.…”

Section: Introductionmentioning

confidence: 99%

Facile preparation of CuWO4 porous films and their photoelectrochemical properties

Lima

Costa

Santos

et al. 2017

Electrochimica Acta

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In this study, the structure and photoelectrochemical properties of CuWO 4 porous films synthesized by a co-precipitation method followed by a hydrothermal treatment were investigated. The film was deposited on fluorine-doped tin oxide (FTO)-conducting glass, from a suspension containing polyethylene glycol, and heat-treated at 500 C for 30 min. X-ray diffraction patterns, the Rietveld refinement data, and the micro-Raman spectrum showed that the CuWO 4 film has a triclinic structure. The optical band gap energy of the film was estimated to be 2.45 eV by the Tauc plot. Field emission scanning electron microcopy images of the films indicated that they are about 4.0 AE 0.5 mm thick. The photoelectrochemical properties of the film were investigated in a Na 2 SO 4 aqueous solution, in the absence of light and under polychromatic irradiation. The CuWO 4 film exhibited photoelectrochemical behavior of a n-type semiconductor, with a negative photopotential and an anodic photocurrent density of 68 mA cm À2 at 0.73 V vs. Ag/AgCl (1.23 V vs. RHE). The n-type photoelectrochemical behavior was confirmed by a chronoamperometry measurement biased condition at + 0.7 V, at different pH values. From these studies, it was noted that when the pH values increased from 3 to 11, the photocurrent density increased about 9 times. Also, the flat band potential (E fb) of the semiconductor was estimated by the Butler-Gärtner model at + 0.34 V, which was utilized to calculate the conduction band edge. The studies presented here reveal that the CuWO 4 porous film is a promising candidate to be applied as a photoanode in photocatalytic processes under irradiation by visible light.

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“…Semiconductors such as TiO 2 , BiVO 4 , WO 3 , and Fe 2 O 3 are the most widely studied metal oxides for PEC water splitting. [5,7,[12][13][14][15][16][17][18][19][20][21][22][23] Very recently, another n-type semiconductor, copper tungstate (CuWO 4 ), has generated great research interest as a robust and inexpensive photocatalyst, [24][25][26][27][28][29][30] as it has an ideal bandgap (Eg) of approximately 2.2 eV and a large visible light absorption range. Its conduction band level is slightly more positive than the proton reduction potential of 0.0 V vs NHE, while its valence band level is thermodynamically suitable for oxygen evolution of 1.23 V vs NHE.…”

Section: Introductionmentioning

confidence: 99%

Significant Enhancement of the Photoelectrochemical Activity of CuWO₄ by using a Cobalt Phosphate Nanoscale Thin Film

2017

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Nanostructured CuWO4 photoanodes were fabricated through a facile electrodeposition method, which was followed by annealing the sample at 500 °C for 2 h. The morphologies, crystalline structure, electronic states, optical behaviors, and photoelectrochemical characteristics of the CuWO4 nanomaterial were examined by scanning electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, UV/Vis spectroscopy, and impedance spectroscopy, showing that the formed triclinic CuWO4 nanoparticles had an indirect band gap of 2.2 eV and strong response to visible light. The cobalt phosphate (CoPi) nanoscale thin film, which was used as a co‐catalyst, was electrodeposited on the CuWO4 surface. The photocurrent of the cobalt phosphate complex‐catalyzed CuWO4 electrodes exhibited an 86 % higher photocurrent response than that of the unmodified CuWO4 nanoparticles under the irradiation of one simulated sun (100 mW cm−2). The kinetics of this photoelectrochemical water splitting process was further investigated, and it was found that a more negative flat band potential and reduced charge transfer resistance were likely the primary reasons behind the enhancement.

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Improved Photocatalytic Activity of TiO₂ on the Addition of CuWO₄

Cited by 29 publications

References 39 publications

Modification of TiO₂ with hBN: high temperature anatase phase stabilisation and photocatalytic degradation of 1,4-dioxane

Modification of TiO₂ with hBN: high temperature anatase phase stabilisation and photocatalytic degradation of 1,4-dioxane

Facile preparation of CuWO4 porous films and their photoelectrochemical properties

Significant Enhancement of the Photoelectrochemical Activity of CuWO₄ by using a Cobalt Phosphate Nanoscale Thin Film

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Improved Photocatalytic Activity of TiO2 on the Addition of CuWO4

Cited by 29 publications

References 39 publications

Modification of TiO2 with hBN: high temperature anatase phase stabilisation and photocatalytic degradation of 1,4-dioxane

Modification of TiO2 with hBN: high temperature anatase phase stabilisation and photocatalytic degradation of 1,4-dioxane

Facile preparation of CuWO4 porous films and their photoelectrochemical properties

Significant Enhancement of the Photoelectrochemical Activity of CuWO4 by using a Cobalt Phosphate Nanoscale Thin Film

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Improved Photocatalytic Activity of TiO₂ on the Addition of CuWO₄

Modification of TiO₂ with hBN: high temperature anatase phase stabilisation and photocatalytic degradation of 1,4-dioxane

Modification of TiO₂ with hBN: high temperature anatase phase stabilisation and photocatalytic degradation of 1,4-dioxane

Significant Enhancement of the Photoelectrochemical Activity of CuWO₄ by using a Cobalt Phosphate Nanoscale Thin Film