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Corrosion resistant metal oxide electrode catalyst for oxygen reduction

外国特許コード F110003171
整理番号 A151-16WO
掲載日 2011年6月17日
出願国 アメリカ合衆国
出願番号 66060205
公報番号 20070259267
公報番号 7919215
出願日 平成17年8月18日(2005.8.18)
公報発行日 平成19年11月8日(2007.11.8)
公報発行日 平成23年4月5日(2011.4.5)
国際出願番号 JP2005015052
国際公開番号 WO2006019128
国際出願日 平成17年8月18日(2005.8.18)
国際公開日 平成18年2月23日(2006.2.23)
優先権データ
  • 特願2004-239589 (2004.8.19) JP
  • 特願2005-093651 (2005.3.29) JP
  • 2005JP015052 (2005.8.18) WO
発明の名称 (英語) Corrosion resistant metal oxide electrode catalyst for oxygen reduction
発明の概要(英語) A corrosion-resistant electrode catalyst for oxygen reduction includes a main catalyst composed of at least one transition metal oxide selected from oxygen-deficient ZrO2, Ta2O5, Nb2O5, TiO2, V2O5, MoO3, and WO3 and a co-catalyst composed of gold.
The electrode catalyst is used in contact with an acidic electrolyte at a potential at least 0.4 V higher than the reversible hydrogen electrode potential.
The catalyst may be used, for example, in such a form that the transition metal oxide in the form of fine particles and gold in the form of fine particles, or fine particles including fine gold particles coated with the transition metal oxide are dispersed on a catalyst carrier which is an electron conductive powder.
This electrode catalyst is suitable as an electrode catalyst for an electrochemical system using an acidic electrolyte in the fields of water electrolysis, inorganic/organic electrolysis, fuel cells, etc.
従来技術、競合技術の概要(英語) BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to electrode catalysts for oxygen reduction for electrochemical systems which use acidic electrolytes in the fields of water electrolysis, inorganic/organic electrolysis, fuel cells, etc.
More particularly, the invention relates to an electrode catalyst for oxygen gas diffusion electrodes, namely, oxygen electrode of fuel cells which use solid polymer electrolyte membranes.
An oxygen electrode means a cathode.
2. Description of Related Art
Noble metals, in particular, platinum, are stable over a wide potential range and have high catalytic activity for various reactions, and thus are used as electrode catalysts for various electrochemical systems.
Some metal oxides are stable in acidic electrolytes over a wide potential range.
Therefore, research has been conducted on enhancing the catalytic activity of platinum by allowing metal oxides to coexist with platinum (for example, Non-patent Documents 1 and 2, and Patent Document 1).
However, the catalytic activity of metal oxides themselves has not been evaluated in detail.
With respect to catalysts having high oxygen reduction activity, other than noble metals, use of spinel-type and perovskite-type oxides (Patent Document 2) and double oxides, such as oxides having a columbite structure, an ilmenite structure, an olivine structure, a NASICON structure, and the like as catalysts for fuel cells, air cells, oxygen sensors, etc. (Patent Document 3) has been known.
Furthermore, an electrode catalyst in which rare-earth oxide fine particles are mixed as a promoter with noble metal catalyst fine particles and which is suitable for use in gas diffusion electrodes for brine electrolysis and the like (Patent Document 4) has also been known.
Furthermore, in an apparatus in which an ozone generator for supplying an ozone-containing gas is installed upstream of a fuel cell that uses a solid polymer electrolyte membrane, a method has been known in which as a catalyst suitable for reduction reaction of ozone, a metal oxide selected from WO3, TiO2, ZrO2, PtO, Sb2O4, and Sb2O3 is used as an electrode catalyst (Patent Document 5).
In addition, as oxide-based electrode catalysts, use of TiO2, Ta2O5, and the like has been known (Patent Documents 6 to 10).
Patent Document 1: Japanese Unexamined Patent Application Publication No. 9-167620
Patent Document 2: Japanese Unexamined Patent Application Publication No. 7-289903
Patent Document 3: Japanese Unexamined Patent Application Publication No. 2003-200051
Patent Document 4: Japanese Unexamined Patent Application Publication No. 2004-197130
Patent Document 5: Japanese Unexamined Patent Application Publication No. 2004-95263
Patent Document 6: Japanese Unexamined Patent Application Publication No. 3-252057
Patent Document 7: Japanese Patent No. 3149629
Patent Document 8: United States Patent Application No. 2004/0058808
Patent Document 9: PCT Japanese Translation Patent Publication No. 2001-522122
Patent Document 10: Japanese Unexamined Patent Application Publication No. 2005-63677
Non-patent Document 1: J. Shim et al., J. Power Sources, 102, 172 (2001)
Non-patent Document 2: A. Katayama, J. Phys. Chem., 84, 376 (1980)

特許請求の範囲(英語) [claim1]
1. A corrosion-resistant oxygen electrode for fuel cell, which uses an acidic electrolyte, comprising: an electrode substrate;
a gold layer as a promoter formed on the electrode substrate; and
a transition metal oxide layer as a catalyst formed on the gold layer, the transition metal oxide layer comprising at least one transition metal oxide selected from Ta2O5, Nb2O5, SnO2, TiO2, V2O5, and ZrOx1 wherein the value of X1 satisfies 0.25<X1<2.0 at a thickness of 20 to 30 nm,
wherein the transition metal oxide layer is in a oxygen-deficient state, and wherein the oxygen electrode is configured as a part of the fuel cell comprising the acidic electrolyte and a fuel electrode.
[claim2]
2. The corrosion-resistant oxygen electrode according to claim 1, wherein the transition metal oxide layer comprises oxygen-deficient Ta2O5.
[claim3]
3. The corrosion-resistant oxygen electrode according to claim 1, wherein the transition metal oxide layer comprises oxygen-deficient Nb2O5.
[claim4]
4. The corrosion-resistant oxygen electrode according to claim 1, wherein the transition metal oxide layer comprises oxygen-deficient SnO2.
[claim5]
5. The corrosion-resistant oxygen electrode according to claim 1, wherein the transition metal oxide layer comprises oxygen-deficient TiO2.
[claim6]
6. The corrosion-resistant oxygen electrode according to claim 1, wherein the transition metal oxide layer comprises oxygen-deficient V2O5.
  • 発明者/出願人(英語)
  • OTA KENICHIRO
  • KAMIYA NOBUYUKI
  • MITSUSHIMA SHIGENORI
  • ISHIHARA AKIMITSU
  • YAN LIU
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
国際特許分類(IPC)
米国特許分類/主・副
  • 429/523
  • 427/115
  • 429/500
  • 429/528
  • 429/532
参考情報 (研究プロジェクト等) CREST Research and Development of System Technologies for Resource Recycling and Minimum Energy Requirement AREA
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