Improved charge separation via Fe-doping of copper tungstate photoanodes

Bohra, Divya; Smith, Wilson A.

doi:10.1039/c4cp05565a

Cited by 85 publications

(55 citation statements)

References 27 publications

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“…Bartlett's group reported that the MnPO-based CuWO 4 photoelectrode exhibited improved PEC performance, corresponding to the cathodic shift of the onset potential for water oxidation by ~ 100 mV and a mild increase in photocurrent density, particularly at low applied bias [11]. In addition, iron doping or hydrogen treatment of the CuWO 4 film increased the bulk electronic conductivity [12]. Another strategy involved formation of heterojunctions between CuWO 4 and a second semiconductor, such as WO 3 , BiVO 4 , and Ag 2 NCN with synergetic enhancement in photocurrent density.…”

Section: Introductionmentioning

confidence: 99%

Nanolayered CuWO4 Decoration on Fluorine-Doped SnO2 Inverse Opals for Solar Water Oxidation

Cho

Gao

Arunachalam

et al. 2018

J. Electrochem. Sci. Technol

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The pristine fluorine-doped SnO 2 (abbreviated as FTO) inverse opal (IO) was developed using a 410 nm polystyrene bead template. The nanolayered copper tungsten oxide (CuWO 4) was decorated on the FTO IO film using a facile electrochemical deposition, subsequently followed by annealing at 500 o C for 90 min. The morphologies, crystalline structure, optical properties and photoelectrochemical characteristics of the FTO and CuWO 4-decorated FTO (briefly denoted as FTO/ CuWO 4) IO film were investigated by field emission scanning electron microscopy, X-ray diffraction, UV-vis spectroscopy and electrochemical impedance spectroscopy, showing FTO IO in the hexagonally closed-pack arrangement with a pore diameter and wall thickness of about 300 nm and 20 nm, respectively. Above this film, the CuWO 4 was electrodeposited by controlling the cycling number in cyclic voltammetry, suggesting that the CuWO 4 formed during 4 cycles (abbreviated as CuWO 4 (4 cycles)) on FTO IO film exhibited partial distribution of CuWO 4 nanoparticles. Additional distribution of CuWO 4 nanoparticles was observed in the case of FTO/CuWO 4 (8 cycles) IO film. The CuWO 4 layer exhibits triclinic structure with an indirect band gap of approximately 2.5 eV and shows the enhanced visible light absorption. The photoelectrochemical (PEC) behavior was evaluated in the 0.5 M Na 2 SO 4 solution under solar illumination, suggesting that the FTO/CuWO 4 (4 cycles) IO films exhibit a photocurrent density (J s c

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Section: Introductionmentioning

confidence: 99%

Nanolayered CuWO4 Decoration on Fluorine-Doped SnO2 Inverse Opals for Solar Water Oxidation

Cho

Gao

Arunachalam

et al. 2018

J. Electrochem. Sci. Technol

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“…Currently, the scientific studies on the electronic properties of pure and doped CuWO 4 have been mainly focused on the photocatalytic (PC) degradation of organic dyes (Rhodamine B, eosin yellow dye and methylene blue) under ultraviolet and visible light [53][54][55], magnetic [56][57][58][59], photoelectrochemical water splitting [60][61][62][63][64], visible and solar-assisted water splitting [65,66], photoanode for solar water oxidation [67,68], electrical transport [69], and photoluminescence (PL) [24,53,70]. An important point to be considered is that the theoretical studies [16,[71][72][73][74][75], performed by means of ab initio calculations based on the density-functional theory (DFT) for the electronic structure of CuWO 4 crystals, have shown that the conduction band (CB) of this oxide is composed of 3d orbitals (Cu atoms) and 5d orbitals (W atoms), while the valence band (VB) is formed of 2p orbitals (O atoms).…”

Section: Introductionmentioning

confidence: 99%

Structural evolution, growth mechanism and photoluminescence properties of CuWO4 nanocrystals

Souza

Sczancoski

Nogueira

et al. 2017

Ultrasonics Sonochemistry

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Copper tungstate (CuWO) crystals were synthesized by the sonochemistry (SC) method, and then, heat treated in a conventional furnace at different temperatures for 1h. The structural evolution, growth mechanism and photoluminescence (PL) properties of these crystals were thoroughly investigated. X-ray diffraction patterns, micro-Raman spectra and Fourier transformed infrared spectra indicated that crystals heat treated and 100°C and 200°C have water molecules in their lattice (copper tungstate dihydrate (CuWO·2HO) with monoclinic structure), when the crystals are calcinated at 300°C have the presence of two phase (CuWO·2HO and CuWO), while the others heat treated at 400°C and 500°C have a single CuWO triclinic structure. Field emission scanning electron microscopy revealed a change in the morphological features of these crystals with the increase of the heat treatment temperature. Transmission electron microscopy (TEM), high resolution-TEM images and selected area electron diffraction were employed to examine the shape, size and structure of these crystals. Ultraviolet-Visible spectra evidenced a decrease of band gap values with the increase of the temperature, which were correlated with the reduction of intermediary energy levels within the band gap. The intense photoluminescence (PL) emission was detected for the sample heat treat at 300°C for 1h, which have a mixture of CuWO·2HO and CuWO phases. Therefore, there is a synergic effect between the intermediary energy levels arising from these two phases during the electronic transitions responsible for PL emissions.

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“…Compared to WO 3 that is only stable in acidic solutions, CuWO 4 shows an excellent stability in aqueous solutions with a pH range of 7-9 [161][162][163]. However, the obtained PEC performances of the CuWO 4 photoanodes are still far from their theoretical values considering the bandgap of 2.3 eV, and the major limitation is attributed to the low charge carrier mobility (~ 0.006 cm 2 V −1 s −1 ) and short charge diffusion length (~ 30 nm) that cause poor charge separation in the bulk CuWO 4 [164,165]. In addition, the surface states also affect the PEC water oxidation performance of the CuWO 4 photoanodes [166,167].…”

Section: Tungsten-based Ternary Oxidesmentioning

confidence: 98%

Recent progress of tungsten- and molybdenum-based semiconductor materials for solar-hydrogen production

Wang

2019

Tungsten

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Semiconductor-based solar water splitting is regarded as one of the most promising technologies for clean hydrogen production. The rational design of semiconductor materials is critically important to achieve high solar-to-hydrogen (STH) conversion efficiencies towards practical applications. A rich family of tungsten-and molybdenum-based materials have been developed as both photocatalysts and cocatalysts for solar-hydrogen production in the past years, providing more opportunities to achieve high solar-to-hydrogen (STH) efficiencies. In this review article, we comprehensively review the recent progress of tungsten-and molybdenum-based materials for solar-hydrogen production. In particular, the strengths and drawbacks of each material system are critically discussed, followed by an overview of the emerging strategies to improve their performances. Finally, the key challenges and possible research directions of tungsten-and molybdenum-based materials are presented, which would provide useful information for the design of efficient semiconductor materials for solar-hydrogen production.

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Improved charge separation via Fe-doping of copper tungstate photoanodes

Cited by 85 publications

References 27 publications

Nanolayered CuWO4 Decoration on Fluorine-Doped SnO2 Inverse Opals for Solar Water Oxidation

Nanolayered CuWO4 Decoration on Fluorine-Doped SnO2 Inverse Opals for Solar Water Oxidation

Structural evolution, growth mechanism and photoluminescence properties of CuWO4 nanocrystals

Recent progress of tungsten- and molybdenum-based semiconductor materials for solar-hydrogen production

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