The embodiments discussed herein are related to oxygen generation electrodes and oxygen generation apparatuses.
Technology of generating an oxygen gas by decomposing water has been studied. A decomposition reaction of water is constituted by a combination of the following half reactions, and the oxygen gas is generated by the latter half reaction (Formula 2). Various propositions have been provided for oxygen generation electrodes suitable for the latter half reaction (Formula 2).
2H2O+2e−→H2+2OH− (Formula 1)
4OH−+4h+→2H2O+O2 (Formula 2)
However, it has been difficult to generate an oxygen gas efficiently with an oxygen generation electrode.
Examples of the related art include International Publication Pamphlet No. WO 2012/137240 and Japanese Laid-open Patent Publication No. 2005-126295.
According to an aspect of the embodiments, an oxygen generation electrode includes: a conductive substrate; and an oxide film formed on a first surface of the conductive substrate and containing Ba, Sn, and La or Sb, wherein the oxide film has a first absorption edge in a visible light region and a second absorption edge in an infrared light region.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention.
An object of the embodiments is to provide an oxygen generation electrode and an oxygen generation apparatus capable of generating an oxygen gas efficiently.
According to an aspect, an appropriate conductive substrate and an appropriate oxide film are contained, and therefore an oxygen gas may be generated efficiently.
Hereinafter, the embodiments will be described in detail with reference to accompanying drawings.
First, a first embodiment will be described below. The first embodiment is an example of an oxygen generation electrode.
As illustrated in
Since the oxide film 12 in the oxygen generation electrode 10 according to the first embodiment has the first absorption edge AE1 and the second absorption edge AE2, water may be strongly photochemically oxidized. Therefore, according to the present embodiment, an oxygen gas may be generated efficiently.
For example, the conductive substrate 11 is an SrTiO3 substrate doped with an n-type impurity such as Nb. For example, the concentration of the n-type impurity is 0.5% by mass to 2.0% by mass. The thickness of the conductive substrate 11 is, for example, 0.1 mm to 1.0 mm. For example, the chemical formula of the oxide contained in the oxide film 12 is represented by BaxLaySnzO3-δ or BaxSbySnzO3-δ. The sum of x, y, and z is 2, but the composition changes to 0.5<(x+y)/z<1 after etching that will be described later. For example, b is 0 or more and less than 0.8. The thickness of the oxide film 12 is, for example, 50 nm to 150 nm. The electrode 13 is, for example, an Au film having a thickness of 10 nm to 100 nm.
In an example, the conductive substrate 11 is an SrTiO3 substrate having a thickness of 0.5 mm and doped with 1% by mass of Nb, the oxide film 12 is a Ba0.95La0.05SnO3 film having a thickness of 80 nm, and the electrode 13 is an Au film having a thickness of 50 nm.
Next, an example of a method for manufacturing the oxygen generation electrode 10 according to the first embodiment will be described. In this example, first, the oxide film 12 is formed on the first surface of the conductive substrate 11 by a pulsed laser deposition (PLD) method. Next, the electrode 13 is deposited on the second surface of the conductive substrate 11.
Next, a second embodiment will be described. The second embodiment relates to an oxygen generation apparatus including the oxygen generation electrode 10.
As illustrated in
In the oxygen generation apparatus 20, the oxygen generation electrode 10 is used as a working electrode. Therefore, by adjusting the potential of the oxygen generation electrode 10 with respect to the reference electrode 23, an oxygen gas may be efficiently generated.
Here, experiments that the present inventors conducted will be described. In this experiment, an oxygen generation apparatus 120 illustrated in
Then, a current that flowed when irradiated with sunlight having an illuminance of 598 mW/cm2 was measured by using a solar simulator. The result of this is illustrated in
In a first comparative example (broken line), the oxygen generation electrode includes an SrTiO3 substrate having a thickness of 0.5 mm and doped with 1% by mass of Nb, and an Au film having a thickness of 50 nm.
In a second comparative example (two-dot chain line), the oxygen generation electrode includes an SrTiO3 substrate having a thickness of 0.5 mm and doped with 1% by mass of Nb, and Au nanopartides. As illustrated in
As illustrated in
In the case where a current is capable of being directly supplied to the conductive substrate 11, the electrode 13 does not have to be provided.
All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
Number | Date | Country | Kind |
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2017-060981 | Mar 2017 | JP | national |
This application is a continuation application of International Application PCT/JP2018/002092 filed on Jan. 24, 2018 and designated the U.S., the entire contents of which are incorporated herein by reference. The International Application PCT/JP2018/002092 is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2017-060981, filed on Mar. 27, 2017, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2018/002092 | Jan 2018 | US |
Child | 16575757 | US |