Visible-light-driven nonsacrificial water oxidation over tungsten trioxide powder modified with two different cocatalysts

Khine, Su Su; Maeda, Kazuhiko; Abe, Ryu; Domen, Kazunari

doi:10.1039/c2ee21801a

Cited by 160 publications

(110 citation statements)

References 57 publications

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“…WO 3 photoanodes in contact with 0.50 M TBAClO 4 in PC exhibited F int values greater than unity at 300-390 nm, owing to current doubling. When WO 3 was used as a photoanode in a regenerative photoelectrochemical cell conguration, the reversible, high-potential redox system 1 mM B 10 …”

Section: Discussionmentioning

confidence: 99%

“…B 10 Br 10 2À exhibits high chemical stability 26 and a reversible, one-electron redox system with a formal oxidation potential of 1.78 V vs. NHE. 31 The Nernst potential of the solution as probed by a Pt wire was observed to be 1.68 V vs. NHE, therefore providing an opportunity to produce large barrier heights, and correspondingly large open-circuit voltages from regenerative photoelectrochemical cells that use this redox system in contact with WO 3 photoanodes.…”

Section: 36mentioning

confidence: 99%

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Photoelectrochemical oxidation of anions by WO3 in aqueous and nonaqueous electrolytes

Coridan

Brunschwig

et al. 2013

Energy Environ. Sci.

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The behavior of WO 3 photoanodes has been investigated in contact with a combination of four anions (Cl ) and three solvents (water, acetonitrile, and propylene carbonate), to elucidate the role of the semiconductor surface, the electrolyte, and redox kinetics on the current density vs. potential properties of n-type WO 3 . In 1.0 M aqueous strong acids, although the flat-band potential (E fb ) of WO 3 was dominated by electrochemical intercalation of protons into WO 3 , the nature of the electrolyte influenced the onset potential (E on ) of the anodic photocurrent. In aprotic solvents, the electrolyte anion shifted both E fb and E on , but did not significantly alter the overall profile of the voltammetric data. For 0.50 M tetra(n-butyl)ammonium perchlorate in propylene carbonate, the internal quantum yield exceeded unity at excitation wavelengths of 300-390 nm, indicative of current doubling. Broader contextElectrolytes are an indispensable constituent in (photo)electrochemistry for forming interfacial double layers and conducting currents. Nonetheless, it is generally considered that the role of electrolytes in (photo)electrochemistry is merely supporting and implicit, because the identity and concentration of electrolytes do not directly determine the electrode potentials and current densities. Results from this work suggest that when in contact with various aqueous and nonaqueous solutions and under simulated solar illumination, thin-lm WO 3 photoanodes oxidized primarily the electrolyte anions in spite of the dominant molarity of the solvent in the electrolyte solutions. The priority of anion oxidation has been utilized to construct nonaqueous, regenerative photoelectrochemical cells that produce large open-circuit voltages. In addition to O 2 (g) evolution from water, such electrolyte effects can result in undesired side reactions, and such processes should be taken into account when WO 3 photoanodes are incorporated into multi-component devices for solar-driven water splitting.

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Section: Discussionmentioning

confidence: 99%

Section: 36mentioning

confidence: 99%

Photoelectrochemical oxidation of anions by WO3 in aqueous and nonaqueous electrolytes

Coridan

Brunschwig

et al. 2013

Energy Environ. Sci.

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“…Note that PtO x /WO 3 is able to produce O 2 from an aqueous NaIO 3 solution under visible light, with an AQY of ca. 10%, 89 at least an order of magnitude higher than that of the total efficiency of the Z-scheme systems consisting of the material as the O 2 evolution building block. This means that the low efficiency of the oxynitride-based Z-scheme is due to the H 2 evolution system that consists of oxynitrides, which appears to be the main obstacle to achieving overall water splitting using these materials.…”

Section: Application To Cr 2 O 3 Modification To Metal Oxidementioning

confidence: 91%

Development of Novel Photocatalyst and Cocatalyst Materials for Water Splitting under Visible Light

Maeda

Domen

2016

Bulletin of the Chemical Society of Japan

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155

110

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Overall water splitting using a semiconductor photocatalyst with sunlight has long been viewed as a potential means of large-scale H 2 production from renewable resources. In general, the reaction can be accomplished when a photocatalyst is modified with a suitable cocatalyst that efficiently promotes water reduction. It is therefore essential to develop both photocatalysts and cocatalysts in harmony. Certain metal (oxy)-nitrides are potential candidates as water-splitting photocatalysts because of their suitable band edge positions for water reduction/oxidation, small band gaps (<3 eV), and stability under irradiation. However, efficient water splitting using visible-light-responsive oxynitrides has still remained a challenge. This account describes our recent developments over the last 10 years of new oxynitrides as well as cocatalysts for overall water splitting under visible light.

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“…Introducing an OEC and/ or HER catalyst on the surface of these semiconductors enhances their photocatalytic activities. [127,128]. However, the noble metal oxides are not abundant and therefore are expensive.…”

Section: Constructing a Complete Photocatalytic System For Oxygen Andmentioning

confidence: 99%

From natural to artificial photosynthesis

Barber

Tran

2013

J. R. Soc. Interface.

323

253

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Demand for energy is projected to increase at least twofold by mid-century relative to the present global consumption because of predicted population and economic growth. This demand could be met, in principle, from fossil energy resources, particularly coal. However, the cumulative nature of carbon dioxide (CO 2 ) emissions demands that stabilizing the atmospheric CO 2 levels to just twice their pre-anthropogenic values by mid-century will be extremely challenging, requiring invention, development and deployment of schemes for carbon-neutral energy production on a scale commensurate with, or larger than, the entire present-day energy supply from all sources combined. Among renewable and exploitable energy resources, nuclear fusion energy or solar energy are by far the largest. However, in both cases, technological breakthroughs are required with nuclear fusion being very difficult, if not impossible on the scale required. On the other hand, 1 h of sunlight falling on our planet is equivalent to all the energy consumed by humans in an entire year. If solar energy is to be a major primary energy source, then it must be stored and despatched on demand to the end user. An especially attractive approach is to store solar energy in the form of chemical bonds as occurs in natural photosynthesis. However, a technology is needed which has a year-round average conversion efficiency significantly higher than currently available by natural photosynthesis so as to reduce land-area requirements and to be independent of food production. Therefore, the scientific challenge is to construct an 'artificial leaf' able to efficiently capture and convert solar energy and then store it in the form of chemical bonds of a high-energy density fuel such as hydrogen while at the same time producing oxygen from water. Realistically, the efficiency target for such a technology must be 10 per cent or better. Here, we review the molecular details of the energy capturing reactions of natural photosynthesis, particularly the water-splitting reaction of photosystem II and the hydrogen-generating reaction of hydrogenases. We then follow on to describe how these two reactions are being mimicked in physico-chemical-based catalytic or electrocatalytic systems with the challenge of creating a large-scale robust and efficient artificial leaf technology.

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Visible-light-driven nonsacrificial water oxidation over tungsten trioxide powder modified with two different cocatalysts

Cited by 160 publications

References 57 publications

Photoelectrochemical oxidation of anions by WO3 in aqueous and nonaqueous electrolytes

Photoelectrochemical oxidation of anions by WO3 in aqueous and nonaqueous electrolytes

Development of Novel Photocatalyst and Cocatalyst Materials for Water Splitting under Visible Light

From natural to artificial photosynthesis

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