Photoelectrochemical Property of Tungsten Oxide Films of Vertically Aligned Flakes for Visible-Light-Induced Water Oxidation

Amano, Fumiaki; Ding, Li; Ohtani, Bunsho

doi:10.1149/1.3525624

Cited by 44 publications

(39 citation statements)

References 25 publications

(41 reference statements)

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“…9 However, to the best of our knowledge WO 3 films prepared by cold spray have not been investigated so far. Compared to other coating techniques employed to prepare WO 3 films like doctor blade, 10 magnetron sputtering, 11 atomic layer deposition, 12 spray pyrolysis, 13 and solvothermal deposition, 14 the cold spray technique readily enables an upscaling for the manufacturing of mechanically stable films on metal substrates to an industrial scale with variable electrode sizes. One disadvantage of employing TiO 2 as a photocatalyst is its large band gap energy of 3.0 eV (rutile) which corresponds to an absorption of light with wavelengths ≤413 nm resulting in the utilization of only a very small part of the incoming sunlight (4%-5%).…”

Section: Introductionmentioning

confidence: 99%

Cold sprayed WO₃and TiO₂electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

et al. 2017

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Films prepared by cold spray have potential applications as photoanodes in electrochemical water splitting and waste water purification. In the present study cold sprayed photoelectrodes produced with WO 3 (active under visible light illumination) and TiO 2 (active under UV illumination) on titanium metal substrates were investigated as photoanodes for the oxidation of water and methanol, respectively. Methanol was chosen as organic model pollutant in acidic electrolytes. Main advantages of the cold sprayed photoelectrodes are the improved metal-semiconductor junctions and the superior mechanical stability.Additionally, the cold spray method can be utilized as a large-scale electrode fabrication technique for photoelectrochemical applications. Incident photon to current efficiencies reveal that cold sprayed TiO 2 / WO 3 photoanodes exhibit the best photoelectrochemical properties with regard to the water and methanol oxidation reactions in comparison with the benchmark photocatalyst Aeroxide TiO 2 P25 due to more efficient harvesting of the total solar light irradiation related to their smaller band gap energies.

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Section: Introductionmentioning

confidence: 99%

Cold sprayed WO₃and TiO₂electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

et al. 2017

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“…This is comparable to the highest observed water oxidation photocurrents for WO 3 films reported in the literature (>2.5 mA cm −2 , AM 1.5, E App = 1.0 V vs. NHE). 18,23,[33][34][35][36] Furthermore, this photocurrent enhancement is achieved without the utilization of sophisticated film geometry design 18 or water oxidation electrocatalysts. [27][28][29][30][31] The relative photocurrent enhancement is most pronounced for films composed of bulk WO 3 particles (enhancement factor of 14 fold), followed by films of 50 nm particles (10 fold) and 30 nm particles (2 fold).…”

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confidence: 99%

Enhancing Majority Carrier Transport in WO₃Water Oxidation Photoanode via Electrochemical Doping

Zhao

Olide

Osterloh

2014

J. Electrochem. Soc.

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Here we report an electrochemical reduction-induced photocurrent enhancement up to an order of magnitude for monoclinic tungsten trioxide (WO 3 ) particulate photoanodes. Electrochemical impedance and photoelectrochemical measurements suggest that the improved performance is attributed to the increase in majority carrier concentration (from 1.5 × 10 18 to 2.5 × 10 21 cm −3 ). This results in higher conductivity and improved electron transport. Minority carrier extraction can be increased by reducing the WO 3 particle size from 200 nm to 50 and 30 nm. The larger solid-liquid interface area promotes the water oxidation rate. By balancing electron/hole extraction with photon absorption in an optimized 30 nm WO 3 particulate electrode, a record water oxidation photocurrent of 3.8 mA/cm 2 , under +1.36 V (vs. RHE) applied bias in 0.1 M Na 2 SO 4 solution at pH = 3.5 is achieved with 50 mW/cm 2 unfiltered Xe illumination. Photoelectrochemical water splitting is an efficient way of converting solar energy to chemical fuel by decomposing water into hydrogen and oxygen.1-9 Among inorganic materials that catalyze the photoelectrolysis of water, WO 3 with a bandgap of 2.6 eV is attractive due to its visible absorption and its photochemical stability in acid aqueous solution up to pH 5. [10][11][12][13] Since it was first reported as a potential photoanode for photoelectrochemical cells (PEC) 27-32 and enhancing WO 3 stability in neutral solution using surface coating. 27 Recently, Yat Li's group reported that a hydrogen treatment at 350• C of hydrothermally synthesized WO 3 films enhanced photoactivity and photostability of the WO 3 electrode, due to the incorporation of W 5+ donors and oxygen vacancies. 24 The W 5+ states are believed to be more resistant to photocorrosion by peroxo-intermediates formed during water oxidation and they improve electron transport in the WO 3 films. Herein, we demonstrate that a similar performance increase can be achieved by in-situ electrochemical reduction of WO 3 particle films at +0.17 V vs. RHE (−0.04 V vs. NHE) in aqueous electrolyte. The reduction increases the water oxidation photocurrent of WO 3 by over an order of magnitude, up to 3.8 mA/cm 2 for an optimized device. This is comparable to the highest observed water oxidation photocurrents for WO 3 films reported in the literature (>2.5 mA cm −2 , AM 1.5, E App = 1.0 V vs. NHE). 18,23,[33][34][35][36] Furthermore, this photocurrent enhancement is achieved without the utilization of sophisticated film geometry design 18 or water oxidation electrocatalysts. [27][28][29][30][31] The relative photocurrent enhancement is most pronounced for films composed of bulk WO 3 particles (enhancement factor of 14 fold), followed by films of 50 nm particles (10 fold) and 30 nm particles (2 fold). The reduction treatment also improves the stability of WO 3 against photocorrosion; after reduction, 50% of the photocurrent persists after 1 hr operation, compared to 10% for an untreated film. The enhancement is preserved in air, when films are at roo...

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“…For PEC water splitting, the low-dimensional nanostructure photoelectrodes have some unique advantages. Compare to photoelectrode with nanoparticles, the low-dimensional nanostructure photoelectrode with ordered arrays can provide a direct electrical pathway for photogenerated charge transport that can effectively reduce charge carrier recombination [31,37,38]. However, there is little work on the composite electrode with two low-dimensional nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Construction of novel Bi2S3 nanobelt @ WO3 nanoplate arrays on FTO glass with high photoelectrochemical activity

Liu

Yang

et al. 2016

International Journal of Hydrogen Energy

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Photoelectrochemical Property of Tungsten Oxide Films of Vertically Aligned Flakes for Visible-Light-Induced Water Oxidation

Cited by 44 publications

References 25 publications

Cold sprayed WO₃and TiO₂electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

Cold sprayed WO₃and TiO₂electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

Enhancing Majority Carrier Transport in WO₃Water Oxidation Photoanode via Electrochemical Doping

Construction of novel Bi2S3 nanobelt @ WO3 nanoplate arrays on FTO glass with high photoelectrochemical activity

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Photoelectrochemical Property of Tungsten Oxide Films of Vertically Aligned Flakes for Visible-Light-Induced Water Oxidation

Cited by 44 publications

References 25 publications

Cold sprayed WO3and TiO2electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

Cold sprayed WO3and TiO2electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

Enhancing Majority Carrier Transport in WO3Water Oxidation Photoanode via Electrochemical Doping

Construction of novel Bi2S3 nanobelt @ WO3 nanoplate arrays on FTO glass with high photoelectrochemical activity

Contact Info

Product

Resources

About

Cold sprayed WO₃and TiO₂electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

Cold sprayed WO₃and TiO₂electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

Enhancing Majority Carrier Transport in WO₃Water Oxidation Photoanode via Electrochemical Doping