JP3138732B2 - Catalyst for oxygen electrode of integrated regeneration type polymer electrolyte fuel cell - Google Patents
Catalyst for oxygen electrode of integrated regeneration type polymer electrolyte fuel cellInfo
- Publication number
- JP3138732B2 JP3138732B2 JP11161827A JP16182799A JP3138732B2 JP 3138732 B2 JP3138732 B2 JP 3138732B2 JP 11161827 A JP11161827 A JP 11161827A JP 16182799 A JP16182799 A JP 16182799A JP 3138732 B2 JP3138732 B2 JP 3138732B2
- Authority
- JP
- Japan
- Prior art keywords
- iridium
- catalyst
- oxygen electrode
- platinum
- fine particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000003054 catalyst Substances 0.000 title claims description 61
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims description 59
- 239000001301 oxygen Substances 0.000 title claims description 59
- 229910052760 oxygen Inorganic materials 0.000 title claims description 59
- 239000000446 fuel Substances 0.000 title claims description 44
- 239000005518 polymer electrolyte Substances 0.000 title claims description 27
- 230000008929 regeneration Effects 0.000 title claims description 16
- 238000011069 regeneration method Methods 0.000 title claims description 16
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 136
- 229910052697 platinum Inorganic materials 0.000 claims description 61
- 239000010419 fine particle Substances 0.000 claims description 56
- 229910052741 iridium Inorganic materials 0.000 claims description 48
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 47
- 150000002504 iridium compounds Chemical class 0.000 claims description 44
- 239000007864 aqueous solution Substances 0.000 claims description 34
- 238000009792 diffusion process Methods 0.000 claims description 24
- 239000007789 gas Substances 0.000 claims description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 239000007787 solid Substances 0.000 claims description 20
- -1 hydroxide ions Chemical class 0.000 claims description 17
- 229920000642 polymer Polymers 0.000 claims description 17
- UOYXEZMXOVJLIH-UHFFFAOYSA-N iridium tetrahydrate Chemical compound O.O.O.O.[Ir] UOYXEZMXOVJLIH-UHFFFAOYSA-N 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 13
- 150000002500 ions Chemical class 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 11
- 229910001854 alkali hydroxide Inorganic materials 0.000 claims description 10
- 238000010304 firing Methods 0.000 claims description 9
- 239000002253 acid Substances 0.000 claims description 8
- 239000003638 chemical reducing agent Substances 0.000 claims description 8
- 239000000243 solution Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 6
- 239000006185 dispersion Substances 0.000 claims description 5
- 230000001376 precipitating effect Effects 0.000 claims description 4
- 238000001354 calcination Methods 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims description 3
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims description 2
- 239000000470 constituent Substances 0.000 claims description 2
- 230000003197 catalytic effect Effects 0.000 description 17
- 239000012528 membrane Substances 0.000 description 13
- 238000006243 chemical reaction Methods 0.000 description 12
- 238000005868 electrolysis reaction Methods 0.000 description 12
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000001257 hydrogen Substances 0.000 description 9
- 229910052739 hydrogen Inorganic materials 0.000 description 9
- 238000006722 reduction reaction Methods 0.000 description 9
- 230000001172 regenerating effect Effects 0.000 description 9
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000004020 conductor Substances 0.000 description 8
- HWLDNSXPUQTBOD-UHFFFAOYSA-N platinum-iridium alloy Chemical compound [Ir].[Pt] HWLDNSXPUQTBOD-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 6
- 239000002244 precipitate Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- IUJMNDNTFMJNEL-UHFFFAOYSA-K iridium(3+);trihydroxide Chemical compound [OH-].[OH-].[OH-].[Ir+3] IUJMNDNTFMJNEL-UHFFFAOYSA-K 0.000 description 5
- 229960005070 ascorbic acid Drugs 0.000 description 4
- 235000010323 ascorbic acid Nutrition 0.000 description 4
- 239000011668 ascorbic acid Substances 0.000 description 4
- 230000005587 bubbling Effects 0.000 description 4
- 229910001873 dinitrogen Inorganic materials 0.000 description 4
- 239000012153 distilled water Substances 0.000 description 4
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 4
- 239000004810 polytetrafluoroethylene Substances 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 239000004480 active ingredient Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 description 3
- 229910000457 iridium oxide Inorganic materials 0.000 description 3
- 230000003472 neutralizing effect Effects 0.000 description 3
- NGNBDVOYPDDBFK-UHFFFAOYSA-N 2-[2,4-di(pentan-2-yl)phenoxy]acetyl chloride Chemical compound CCCC(C)C1=CC=C(OCC(Cl)=O)C(C(C)CCC)=C1 NGNBDVOYPDDBFK-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 229920000557 Nafion® Polymers 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000003411 electrode reaction Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000003014 ion exchange membrane Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000011163 secondary particle Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229920003934 Aciplex® Polymers 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229920003935 Flemion® Polymers 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 229910000575 Ir alloy Inorganic materials 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910026551 ZrC Inorganic materials 0.000 description 1
- OTCHGXYCWNXDOA-UHFFFAOYSA-N [C].[Zr] Chemical compound [C].[Zr] OTCHGXYCWNXDOA-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 229920001940 conductive polymer Polymers 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- FPHQLDRCDMDGQW-UHFFFAOYSA-N iridium Chemical compound [Ir].[Ir] FPHQLDRCDMDGQW-UHFFFAOYSA-N 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- MTPVUVINMAGMJL-UHFFFAOYSA-N trimethyl(1,1,2,2,2-pentafluoroethyl)silane Chemical compound C[Si](C)(C)C(F)(F)C(F)(F)F MTPVUVINMAGMJL-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、一体化再生型固体
高分子型燃料電池の酸素極用触媒、一体化再生型固体高
分子型燃料電池の酸素極、及び一体化再生型固体高分子
型燃料電池に関する。The present invention relates to a catalyst for an oxygen electrode of an integrated regeneration type polymer electrolyte fuel cell, an oxygen electrode of an integrated regeneration type polymer electrolyte fuel cell, and an integrated regeneration type polymer electrolyte fuel cell. Related to fuel cells.
【０００２】[0002]
【従来の技術】固体高分子電解質膜を用いる電気化学プ
ロセスは、エネルギー変換効率が高く、省エネルギーで
クリーンな極めて優れたエネルギー変換システムであ
る。特に、固体高分子水電解や固体高分子型燃料電池
は、水素エネルギーシステムの根幹を担う基本技術とし
て期待されているが、その実用化のためには、コスト低
減が強く望まれている。2. Description of the Related Art An electrochemical process using a solid polymer electrolyte membrane is a very excellent energy conversion system having high energy conversion efficiency, energy saving and cleanness. In particular, polymer electrolyte water electrolysis and polymer electrolyte fuel cells are expected as basic technologies that are the basis of hydrogen energy systems, but cost reduction is strongly desired for their practical use.
【０００３】一体化再生型燃料電池とは、通常は別々の
セルで運転されている燃料電池と水電解を、同一のセル
で運転できるようにしたものであり、これによりシステ
ムの大幅なコストダウンが期待されている。しかしなが
ら、固体高分子水電解セルの酸素発生極に用いられるイ
リジウムは、酸素発生反応には活性を示すものの、燃料
電池の酸素極反応（酸素還元）についての活性は白金と
比較して劣っており、一方、固体高分子型燃料電池の酸
素極に用いられる白金は、酸素還元反応には優れた活性
を示すものの、水電解の酸素発生反応に対する活性はイ
リジウムと比較して劣るものである。[0003] An integrated regenerative fuel cell is one in which a fuel cell and water electrolysis, which are usually operated in separate cells, can be operated in the same cell, thereby greatly reducing the cost of the system. Is expected. However, although iridium used in the oxygen generating electrode of the solid polymer water electrolysis cell is active in the oxygen generating reaction, the activity of the fuel cell in the oxygen electrode reaction (oxygen reduction) is inferior to platinum. On the other hand, platinum used in the oxygen electrode of the polymer electrolyte fuel cell has excellent activity in the oxygen reduction reaction, but is inferior in activity to the oxygen generation reaction in water electrolysis as compared to iridium.
【０００４】[0004]
【発明が解決しようとする課題】本発明の主な目的は、
酸素発生反応に対する触媒活性と酸素還元反応に対する
触媒活性の両方に優れ、一体化再生型燃料電池用の酸素
極用触媒として優れた特性を発揮し得る触媒材料を提供
することである。SUMMARY OF THE INVENTION The main object of the present invention is to:
An object of the present invention is to provide a catalyst material which is excellent in both catalytic activity for an oxygen generation reaction and catalytic activity for an oxygen reduction reaction, and can exhibit excellent characteristics as an oxygen electrode catalyst for an integrated regenerative fuel cell.
【０００５】[0005]
【課題を解決するための手段】本発明者は、上述した如
き課題に鑑みて鋭意研究を重ねた結果、イリジウムに水
酸化物イオンが配位したイリジウム錯イオンを含有する
水溶液から、水酸化イリジウム水和物を沈殿析出させ、
これを比較的低温の空気中で焼成して得られるイリジウ
ム化合物は、優れた触媒活性を有する高比表面積の粒子
となり、これを白金微粒子と混合することによって、酸
素発生反応と酸素還元反応の両反応に対する活性に優れ
た触媒が得られることを見出した。更に、イリジウム錯
体を含有する水溶液中に白金微粒子を分散させ、この水
溶液中から水酸化イリジウム水和物を沈殿析出させ、こ
れを焼成することによって、イリジウム化合物の微粒子
が白金微粒子に均一に分散担持された高活性な触媒とな
り、この触媒は、一体化再生型燃料電池用の酸素極用触
媒として、より一層優れた特性を発揮できることを見出
し、ここに本発明を完成するに至った。Means for Solving the Problems The present inventor has conducted intensive studies in view of the above-mentioned problems, and as a result, obtained from an aqueous solution containing an iridium complex ion in which hydroxide ions are coordinated with iridium hydroxide. Precipitate the hydrate,
The iridium compound obtained by calcining this in air at relatively low temperature becomes particles having a high specific surface area having excellent catalytic activity, and by mixing this with platinum fine particles, both the oxygen generation reaction and the oxygen reduction reaction are performed. It has been found that a catalyst having excellent activity for the reaction can be obtained. Further, by dispersing platinum fine particles in an aqueous solution containing an iridium complex, iridium hydroxide hydrate is precipitated and precipitated from the aqueous solution, and by firing this, the fine particles of the iridium compound are uniformly dispersed and supported on the platinum fine particles. It has been found that this catalyst can exhibit more excellent characteristics as an oxygen electrode catalyst for an integrated regenerative fuel cell, and thus completed the present invention.
【０００６】即ち、本発明は、下記の一体化再生型固体
高分子型燃料電池の酸素極用触媒、一体化再生型固体高
分子型燃料電池の酸素極、及び一体化再生型固体高分子
型燃料電池を提供するものである。 １．イリジウムに水酸化物イオンが配位したイリジウム
錯イオンを含有する水溶液から、水酸化イリジウム水和
物を沈殿析出させた後、含酸素雰囲気中で２００〜７０
０℃で焼成して得られるイリジウム化合物と、白金微粒
子の混合物からなる一体化再生型固体高分子型燃料電池
の酸素極用触媒。 ２．イリジウムに水酸化物イオンが配位したイリジウム
錯イオンを含有する水溶液中に白金微粒子を分散させた
分散液から、水酸化イリジウム水和物を沈殿析出させた
後、含酸素雰囲気中で２００〜７００℃で焼成して得ら
れる、イリジウム化合物を担持した白金微粒子からなる
一体化再生型固体高分子型燃料電池の酸素極用触媒。 ３．イリジウムに水酸化物イオンが配位したイリジウム
錯イオンを含有する水溶液が、水酸化アルカリ水溶液に
イリジウム錯体を添加するか、又はイリジウム錯体を含
有する水溶液に水酸化アルカリ化合物を添加して得られ
るものである上記項１又は２に記載の酸素極用触媒。 ４．水酸化イリジウム水和物を沈殿析出させる方法が、
イリジウム錯イオンを含有する水溶液に酸を添加する方
法である上記項１〜３のいずれかに記載の酸素極用触
媒。 ５．還元剤の存在下に水酸化イリジウム水和物を沈殿析
出させる上記項１〜４のいずれかに記載の酸素極用触
媒。 ６．焼成温度が３００〜５００℃である上記項１〜５の
いずれかに記載の酸素極用触媒。 ７．白金微粒子が白金黒である上記項１〜６のいずれか
に記載の酸素極用触媒。 ８．白金微粒子が担体に担持されたものである上記項１
〜７のいずれかに記載の酸素極用触媒。 ９．上記項１〜８のいずれかに記載の触媒を含むガス拡
散電極である一体化再生型固体高分子型燃料電池の酸素
極。 １０．上記項９に記載の酸素極を構成要素とする一体化
再生型固体高分子型燃料電池。That is, the present invention provides the following catalyst for an oxygen electrode of an integrated regeneration type polymer electrolyte fuel cell, an oxygen electrode of an integrated regeneration type polymer electrolyte fuel cell, and an integrated regeneration type polymer electrolyte fuel cell. A fuel cell is provided. 1. After iridium hydroxide hydrate is precipitated from an aqueous solution containing an iridium complex ion in which a hydroxide ion is coordinated with iridium, the iridium hydroxide is hydrated in an oxygen-containing atmosphere at 200 to 70%.
An oxygen electrode catalyst for an integrated regenerating solid polymer fuel cell comprising a mixture of an iridium compound obtained by firing at 0 ° C. and platinum fine particles. 2. After iridium hydroxide hydrate is precipitated from a dispersion in which platinum fine particles are dispersed in an aqueous solution containing an iridium complex ion in which a hydroxide ion is coordinated with iridium, the iridium hydroxide is 200 to 700 in an oxygen-containing atmosphere. A catalyst for an oxygen electrode of an integrated regenerating solid polymer fuel cell comprising platinum fine particles carrying an iridium compound, which is obtained by firing at a temperature of ° C. 3. An aqueous solution containing an iridium complex ion in which a hydroxide ion is coordinated with iridium is obtained by adding an iridium complex to an aqueous alkali hydroxide solution or by adding an alkali hydroxide compound to an aqueous solution containing an iridium complex. Item 3. The oxygen electrode catalyst according to Item 1 or 2, above. 4. The method of precipitating iridium hydroxide hydrate,
Item 4. The catalyst for an oxygen electrode according to any one of Items 1 to 3, which is a method for adding an acid to an aqueous solution containing an iridium complex ion. 5. Item 5. The catalyst for an oxygen electrode according to any one of Items 1 to 4, wherein iridium hydroxide hydrate is precipitated in the presence of a reducing agent. 6. Item 6. The oxygen electrode catalyst according to any one of Items 1 to 5, wherein the calcination temperature is 300 to 500 ° C. 7. Item 7. The oxygen electrode catalyst according to any one of Items 1 to 6, wherein the platinum fine particles are platinum black. 8. Item 1. The above item 1, wherein the platinum fine particles are supported on a carrier.
The catalyst for an oxygen electrode according to any one of claims 1 to 7. 9. Item 9. An oxygen electrode of an integrated regeneration type polymer electrolyte fuel cell which is a gas diffusion electrode containing the catalyst according to any one of Items 1 to 8. 10. Item 10. An integrated regenerating solid polymer fuel cell comprising the oxygen electrode according to Item 9 as a constituent element.
【０００７】[0007]
【発明の実施の形態】本発明の触媒で用いるイリジウム
化合物を得るには、まず、イリジウムに水酸化物イオン
が配位したイリジウム錯イオンを含有する水溶液から、
水酸化イリジウム水和物を沈殿析出させる。BEST MODE FOR CARRYING OUT THE INVENTION In order to obtain an iridium compound used in the catalyst of the present invention, first, an aqueous solution containing an iridium complex ion in which a hydroxide ion is coordinated with iridium is prepared.
Iridium hydroxide hydrate precipitates out.
【０００８】この様なイリジウムに水酸化物イオンが配
位したイリジウム錯イオンを含有する水溶液は、例え
ば、水酸化アルカリ化合物を含有する水溶液中にイリジ
ウム錯体を添加するか、或いは、イリジウム錯体を含有
する水溶液に、水酸化アルカリ化合物を添加することに
よって調製できる。[0008] Such an aqueous solution containing an iridium complex ion in which hydroxide ions are coordinated with iridium is prepared, for example, by adding an iridium complex to an aqueous solution containing an alkali hydroxide compound or containing an iridium complex. It can be prepared by adding an alkali hydroxide compound to an aqueous solution to be prepared.
【０００９】原料として用いるイリジウム錯体として
は、水溶性のイリジウム錯体であればよく、具体例とし
ては、Ｈ2［ＩｒＣｌ6］、Ｋ2［ＩｒＣｌ6］、Ｎａ
2［ＩｒＣｌ6］、（ＮＨ4）2［ＩｒＣｌ6］、Ｈ3［Ｉｒ
Ｃｌ6］、Ｋ3［ＩｒＣｌ6］、（ＮＨ4）3［ＩｒＣｌ6］
等を挙げることができる。イリジウム錯体の濃度は、
０．００５〜０．０５モル／ｌ程度とすることが好まし
い。The iridium complex used as a raw material may be any water-soluble iridium complex, and specific examples include H 2 [IrCl 6 ], K 2 [IrCl 6 ], Na
2 [IrCl 6 ], (NH 4 ) 2 [IrCl 6 ], H 3 [Ir
Cl 6 ], K 3 [IrCl 6 ], (NH 4 ) 3 [IrCl 6 ]
And the like. The concentration of the iridium complex is
It is preferable to set it to about 0.005 to 0.05 mol / l.
【００１０】水酸化アルカリ化合物としては、例えば、
水酸化カリウム、水酸化ナトリウム等を用いることがで
きる。水酸化アルカリ化合物の添加量は、水溶液中の水
酸化アルカリ化合物濃度が０．０５〜０．５モル／ｌ程
度であって、イリジウム錯体の７〜１０倍モル程度とす
ることが適当である。この様に水酸化アルカリ化合物を
添加することによって、水溶液中で、イリジウムに水酸
化物イオンが６個配位した［Ｉｒ（ＯＨ）6］3-が形成
される。この際の液温は、３０〜５０℃程度とすればよ
く、反応時間は、３〜５時間程度とすればよい。As the alkali hydroxide compound, for example,
Potassium hydroxide, sodium hydroxide and the like can be used. The amount of the alkali hydroxide compound added is such that the concentration of the alkali hydroxide compound in the aqueous solution is about 0.05 to 0.5 mol / l and about 7 to 10 times the mol of the iridium complex. By adding an alkali hydroxide compound in this way, [Ir (OH) 6 ] 3− in which six hydroxide ions are coordinated to iridium in an aqueous solution is formed. The liquid temperature at this time may be about 30 to 50 ° C., and the reaction time may be about 3 to 5 hours.
【００１１】次いで、この水溶液に酸を加えて中和する
ことによって、水酸化イリジウムの水和物を沈殿析出さ
せる。酸としては、例えば、過塩素酸水溶液、塩酸、硫
酸等を用いることができる。酸の添加量は、水酸化イリ
ジウム水和物の沈殿が生じるための必要な量とすればよ
く、通常は、水溶液のｐＨが７．５〜８．５程度となる
量とすればよい。この様にして、イリジウム錯イオンを
含有する水溶液に酸を加えて中和することによって、
［Ｉｒ（ＯＨ）6］3-がコロイド状の［Ｉｒ（ＯＨ）
3（Ｈ2Ｏ）3］に変換されて沈殿が生じる。Next, the hydrate of iridium hydroxide is precipitated by neutralizing the aqueous solution by adding an acid. As the acid, for example, an aqueous solution of perchloric acid, hydrochloric acid, sulfuric acid and the like can be used. The amount of the acid to be added may be an amount necessary for the precipitation of iridium hydroxide hydrate to occur, and usually, the amount of the acid may be such that the pH of the aqueous solution becomes about 7.5 to 8.5. Thus, by neutralizing the aqueous solution containing the iridium complex ion by adding an acid,
[Ir (OH) 6 ] 3- is colloidal [Ir (OH) 6 ]
3 (H 2 O) 3 ] to form a precipitate.
【００１２】なお、イリジウム錯体を含有する水溶液を
中和する際に、イリジウム錯体が酸化されて塩化物イオ
ンが混入することを避けるために、空気中等の含酸素雰
囲気中で反応を行う場合には、イリジウム錯体を含有す
る水溶液中に、還元剤を添加することが好ましい。還元
剤としては、形成されるイリジウム化合物中に残留する
ことを避けるために、後述する焼成工程で分解されるも
のが好ましく、例えば、アスコルビン酸等を用いること
ができる。還元剤の配合量については、特に限定的では
ないが、アスコルビン酸を用いる場合には、０．１〜
０．２ｇ／ｌ程度とすることが適当である。また、還元
剤を添加する方法に代えて、窒素等の不活性ガス雰囲気
中で中和反応を行うことによっても、イリジウム錯体の
酸化を抑制することができる。When neutralizing the aqueous solution containing the iridium complex, in order to avoid oxidation of the iridium complex and contamination of chloride ions, the reaction is carried out in an oxygen-containing atmosphere such as air. It is preferable to add a reducing agent to the aqueous solution containing the iridium complex. As the reducing agent, those which are decomposed in a firing step described later are preferable in order to avoid remaining in the formed iridium compound, and for example, ascorbic acid or the like can be used. The amount of the reducing agent is not particularly limited, but when ascorbic acid is used, 0.1 to
Suitably, it is about 0.2 g / l. Further, instead of the method of adding the reducing agent, the oxidation of the iridium complex can be suppressed by performing the neutralization reaction in an atmosphere of an inert gas such as nitrogen.
【００１３】この様にして生じた水酸化イリジウム水和
物は、液中の塩化物イオンの混入を防ぐために十分に水
洗し、その後、乾燥して水分を十分除去した後、空気中
等の含酸素雰囲気中で、２００〜７００℃程度、好まし
くは、３００〜５００℃程度、更に好ましくは３５０〜
４５０℃程度で１〜２時間程度焼成することによって、
本発明触媒の有効成分とするイリジウム化合物を得るこ
とができる。The iridium hydroxide hydrate thus produced is sufficiently washed with water to prevent chloride ions from being mixed in the liquid, and then dried to sufficiently remove water. In an atmosphere, about 200 to 700 ° C, preferably about 300 to 500 ° C, more preferably about 350 to
By firing at about 450 ° C. for about 1 to 2 hours,
An iridium compound as an active ingredient of the catalyst of the present invention can be obtained.
【００１４】この様にして、イリジウム錯体を含有する
水溶液から穏和な条件下で沈殿析出した水酸化イリジウ
ム水和物を、含酸素雰囲気中で比較的低温度で焼成する
ことによって、比表面積が高く、優れた触媒活性を有す
るイリジウム化合物を得るとができる。形成されるイリ
ジウム化合物は、超微粒子状の化合物が、比較的疎に凝
集した高比表面積の粒子となり、通常は、２次粒子の粒
径が１００ｎｍ程度以下で、比表面積は２０〜５０ｍ2
／ｇ程度となる。形成されるイリジウム化合物は、焼成
条件等によって、イリジウム酸化物、イリジウム水酸化
物、金属イリジウム、イリジウム合金、これらの混合物
等になる。本発明では、特に、４００℃程度で焼成して
得られる高比表面積の酸化イリジウムを主成分とするイ
リジウム化合物が好ましい。In this manner, iridium hydroxide hydrate precipitated from an aqueous solution containing an iridium complex under mild conditions is calcined at a relatively low temperature in an oxygen-containing atmosphere to thereby increase the specific surface area. An iridium compound having excellent catalytic activity can be obtained. The iridium compound to be formed is a particle having a high specific surface area in which the ultrafine compound is relatively sparsely agglomerated. Usually, the particle diameter of the secondary particles is about 100 nm or less, and the specific surface area is 20 to 50 m 2.
/ G. The formed iridium compound becomes iridium oxide, iridium hydroxide, metal iridium, iridium alloy, a mixture thereof, or the like depending on the firing conditions and the like. In the present invention, an iridium compound mainly containing iridium oxide having a high specific surface area obtained by firing at about 400 ° C. is particularly preferable.
【００１５】焼成後のイリジウム化合物は、乳鉢等を用
いて十分に分散させた後、触媒の有効成分として使用す
ることが好ましい。The fired iridium compound is preferably used as an active ingredient of a catalyst after being sufficiently dispersed using a mortar or the like.
【００１６】本発明の触媒に配合するもう一方の有効成
分である白金微粒子としては、従来から固体高分子型燃
料電池に使用されている白金触媒と同様の白金微粒子を
用いればよい。本発明では、特に限定的ではないが、高
活性を得るために、高比表面積の白金微粒子が好まし
く、例えば、比表面積が１０ｍ2／ｇ程度以上の白金黒
等を好適に用いることができる。As the platinum fine particles as the other active ingredient to be added to the catalyst of the present invention, the same platinum fine particles as those used in conventional polymer electrolyte fuel cells may be used. In the present invention, although not particularly limited, platinum particles having a high specific surface area are preferable in order to obtain high activity. For example, platinum black having a specific surface area of about 10 m 2 / g or more can be suitably used.
【００１７】また、白金微粒子をそのまま用いる他に、
担体上に担持された白金微粒子を用いても良い。担体と
しては、金、ルテニウム、チタン等の酸性雰囲気下で腐
食されない金属の微粒子、炭化チタン、炭化ジルコニウ
ム等の導電性セラミックスの微粒子等を使用できる。こ
れらの担体に白金微粒子を担持させる方法については、
公知の方法に従えばよく、例えば、塩化白金酸エタノー
ル溶液を担体に含浸させた後、水素気流中で１００〜３
００℃程度、好ましくは２００℃程度で還元することに
よって、担体表面に白金微粒子を析出させることができ
る。担体上への白金微粒子の担持量については、通常、
担体と白金微粒子との合計量を１００重量％程度とし
て、１〜２０重量％程度とすればよい。担体上に担持さ
れた白金微粒子を用いることによって、白金微粒子の利
用効率が向上し、より少ない白金使用量で十分な触媒活
性を発揮できる。In addition to using platinum fine particles as they are,
Platinum fine particles supported on a carrier may be used. As the carrier, fine particles of a metal such as gold, ruthenium, and titanium that are not corroded in an acidic atmosphere, and fine particles of a conductive ceramic such as titanium carbide and zirconium carbide can be used. Regarding the method of supporting platinum fine particles on these carriers,
A known method may be used. For example, after impregnating the carrier with an ethanol solution of chloroplatinic acid, the support is impregnated with 100 to 3 in a hydrogen stream.
By performing the reduction at about 00 ° C., preferably about 200 ° C., platinum fine particles can be precipitated on the surface of the carrier. The amount of platinum fine particles carried on the carrier is usually
The total amount of the carrier and the platinum fine particles may be about 100% by weight, and may be about 1 to 20% by weight. By using the platinum fine particles supported on a carrier, the utilization efficiency of the platinum fine particles is improved, and sufficient catalytic activity can be exhibited with a smaller amount of platinum used.
【００１８】本発明の触媒は、上記した方法で得られた
イリジウム化合物と白金微粒子を混合したものであり、
高比表面積のイリジウム化合物と白金微粒子を混合する
ことによって、優れた触媒活性を有するイリジウム化合
物と白金微粒子が均一に分散した混合触媒となり、酸素
発生反応に対する触媒活性と酸素還元反応に対する触媒
活性の両方に優れたものとなる。The catalyst of the present invention is a mixture of the iridium compound obtained by the above method and platinum fine particles,
By mixing a high specific surface area iridium compound and platinum fine particles, a mixed catalyst in which the iridium compound and platinum fine particles having excellent catalytic activity are uniformly dispersed is obtained, and both the catalytic activity for the oxygen generation reaction and the catalytic activity for the oxygen reduction reaction are obtained. It will be excellent.
【００１９】イリジウム化合物と白金微粒子の混合割合
は、イリジウム化合物：白金微粒子（モル比）＝１：１
〜１：１５程度とすればよく、１：３〜１：１０程度と
することがより好ましい。イリジウム化合物と白金粒子
の混合方法については、特に限定はなく、例えば、ボー
ルミル、乳鉢等を用いて均一に混合すればよい。なお、
担体上に担持された白金微粒子を用いる場合には、上記
した混合割合と比べてより少量の白金量で良好な触媒活
性を示すことも可能である。The mixing ratio of the iridium compound and the platinum fine particles is such that the iridium compound: platinum fine particles (molar ratio) = 1: 1.
The ratio may be set to about 1:15, more preferably about 1: 3 to 1:10. The method of mixing the iridium compound and the platinum particles is not particularly limited, and may be, for example, uniformly mixed using a ball mill, a mortar or the like. In addition,
In the case of using platinum fine particles supported on a carrier, it is possible to exhibit good catalytic activity with a smaller amount of platinum as compared with the mixing ratio described above.
【００２０】また、本発明によれば、上記イリジウム化
合物と白金微粒子を単に混合するだけではなく、白金微
粒子上にイリジウム化合物の微粒子を担持させることに
よって、上記混合触媒と比べて、より一層優れた触媒活
性を有する触媒を得ることができる。Further, according to the present invention, not only the iridium compound and the fine platinum particles are simply mixed, but also the fine iridium compound particles are supported on the fine platinum particles, whereby the iridium compound is more excellent than the mixed catalyst. A catalyst having catalytic activity can be obtained.
【００２１】白金微粒子上にイリジウム化合物を担持さ
せるには、まず、上記したイリジウム化合物微粒子の調
製に用いたものと同様のイリジウム錯体含有水溶液中
に、白金微粒子を分散させた後、上記した方法と同様に
して水酸化イリジウム水和物を沈殿析出させればよい。
白金微粒子は、還元剤を加える前、又は還元剤を加えた
直後に添加すればよい。In order to support the iridium compound on the platinum fine particles, first, the platinum fine particles are dispersed in an aqueous solution containing an iridium complex similar to that used for preparing the above-mentioned iridium compound fine particles. Similarly, iridium hydroxide hydrate may be precipitated.
The platinum fine particles may be added before adding the reducing agent or immediately after adding the reducing agent.
【００２２】白金微粒子へのイリジウム微粒子の担持量
は、イリジウム微粒子：白金微粒子（モル比）＝１：１
〜１：９程度とすることが好ましく、１：４〜１：９程
度とすることがより好ましい。該水溶液中への白金微粒
子の添加量は、目的とする白金微粒子へのイリジウム微
粒子の担持量に応じて決めればよい。The loading amount of iridium fine particles on the platinum fine particles is as follows: iridium fine particles: platinum fine particles (molar ratio) = 1: 1.
About 1: 9, more preferably about 1: 4 to 1: 9. The amount of platinum fine particles added to the aqueous solution may be determined according to the amount of iridium fine particles supported on the target platinum fine particles.
【００２３】イリジウムを沈殿析出させる際に使用する
原料成分の種類、水酸化イリジウム水和物を沈殿析出さ
せる方法等については、上記したイリジウム化合物を作
製する場合と同様とすればよい。The kind of raw material components used for precipitating and depositing iridium, the method for precipitating and depositing iridium hydroxide hydrate, and the like may be the same as those for producing the above-mentioned iridium compound.
【００２４】次いで、上記したイリジウム化合物微粒子
の調製と同様にして、焼成することによって、白金微粒
子上にイリジウム化合物を担持させることができる。得
られた担持物は、白金微粒子上に、高比表面積のイリジ
ウム化合物が均一に分散担持されたものとなり、酸素発
生反応に対する触媒活性と酸素還元反応に対する触媒活
性の両方について、非常に優れた特性を発揮するものと
なる。白金微粒子上に担持されるイリジウム化合物につ
いては、上記した場合と同様に、通常、粒径が１００ｎ
ｍ程度以下で、比表面積は２０〜５０ｍ2／ｇ程度とな
る。Next, the iridium compound can be supported on the platinum fine particles by firing in the same manner as in the preparation of the iridium compound fine particles described above. The resulting support has a high specific surface area iridium compound uniformly dispersed and supported on platinum fine particles, and has excellent characteristics in both the catalytic activity for the oxygen generation reaction and the catalytic activity for the oxygen reduction reaction. Will be demonstrated. As for the iridium compound supported on the platinum fine particles, the particle size is usually 100 n, as in the case described above.
Below about m, the specific surface area is about 20 to 50 m 2 / g.
【００２５】また、この方法においても、白金微粒子に
代えて、担体上に担持させた白金微粒子を用いることが
できる。この場合に使用できる、担体上に担持させた白
金微粒子は、上述したイリジウム化合物と白金微粒子の
混合物からなる触媒で使用するものと同様でよい。Also in this method, platinum fine particles supported on a carrier can be used instead of platinum fine particles. The platinum fine particles supported on the carrier, which can be used in this case, may be the same as those used for the above-mentioned catalyst comprising a mixture of the iridium compound and the platinum fine particles.
【００２６】以上の方法で得られたイリジウム化合物と
白金微粒子の混合物からなるイリジウム白金触媒、及び
白金微粒子上にイリジウム化合物を担持させたイリジウ
ム白金触媒は、いずれも一体化再生型固体高分子型燃料
電池用の酸素極の触媒として用いることができる。The iridium platinum catalyst comprising a mixture of the iridium compound and the platinum fine particles obtained by the above method and the iridium platinum catalyst having the iridium compound supported on the platinum fine particles are both an integrated regenerated solid polymer type fuel. It can be used as an oxygen electrode catalyst for batteries.
【００２７】該酸素極の構造は、通常のガス拡散電極と
同様の構造とすればよく、本発明のイリジウム白金触媒
を用いる他は、常法に従って作製することができる。例
えば、本発明の触媒を含むシート状のガス拡散電極を作
製するには、イリジウム白金触媒と、ポリテトラフルオ
ロエチレン等のフッ素系樹脂を両者の合計量を１００重
量％として、フッ素系樹脂が１０〜４０重量％程度とな
る割合で混合し、更に、必要に応じて、公知の造孔剤等
を加えた混合物を、シート状に成形し、窒素等の不活性
ガス雰囲気中で３２０〜３８０℃程度で焼成することに
よって、２０〜２００μｍ程度の厚さの多孔質のシート
状焼結体からなるガス拡散電極を得ることができる。更
に、このガス拡散電極には、一体化再生型固体高分子型
燃料電池において高分子イオン交換膜として使用する固
体高分子電解質と同一又は類似したカチオン伝導性を有
する高分子化合物を含有する分散液を塗布し含浸させて
乾燥することによって、該ガス拡散電極中に固体高分子
電解質成分を拡散させて、電極反応領域を３次元化し
て、電極性能を更に向上させることもできる。The structure of the oxygen electrode may be the same as that of a normal gas diffusion electrode, and can be manufactured according to a conventional method except that the iridium platinum catalyst of the present invention is used. For example, in order to prepare a sheet-shaped gas diffusion electrode containing the catalyst of the present invention, the total amount of both the iridium platinum catalyst and the fluororesin such as polytetrafluoroethylene is 100% by weight, and the fluororesin is 10%. A mixture obtained by mixing at a ratio of about 40% by weight and further adding a known pore-forming agent and the like, if necessary, is formed into a sheet, and is heated to 320 to 380 ° C. in an inert gas atmosphere such as nitrogen. By sintering to a degree, a gas diffusion electrode made of a porous sheet-shaped sintered body having a thickness of about 20 to 200 μm can be obtained. Further, the gas diffusion electrode includes a dispersion containing a polymer compound having the same or similar cation conductivity as the solid polymer electrolyte used as the polymer ion exchange membrane in the integrated regeneration type solid polymer fuel cell. By coating, impregnating and drying, the solid polymer electrolyte component is diffused in the gas diffusion electrode, the electrode reaction region is made three-dimensional, and the electrode performance can be further improved.
【００２８】また、そのほかに、固体高分子電解質と同
一種類の高分子化合物を含有する分散液とイリジウム白
金触媒を混合してスラリー状とし、これを、ポリテトラ
フルオロエチレン等のフッ素系樹脂の基材や固体高分子
電解質膜に塗布し、乾燥することによっても、本発明の
イリジウム白金触媒を含有するガス拡散電極を作製する
ことができる。In addition, a dispersion containing a polymer compound of the same type as the solid polymer electrolyte and an iridium platinum catalyst are mixed to form a slurry, and this is formed into a slurry of a fluorine-based resin such as polytetrafluoroethylene. A gas diffusion electrode containing the iridium platinum catalyst of the present invention can also be prepared by applying the composition to a material or a solid polymer electrolyte membrane and drying.
【００２９】本発明の触媒を用いる一体化再生型固体高
分子型燃料電池は、固体高分子型水電解と固体高分子型
燃料電池の反応を同一の電気化学セルで行うものであ
り、固体高分子電解質膜の両側に、酸素極と水素極とし
て、それぞれガス拡散電極を配置した構造である。該一
体化再生型固体高分子型燃料電池では、酸素極として
は、上記した本発明のイリジウム白金触媒を触媒成分と
するガス拡散電極を用い、水素極としては、白金触媒、
カーボン担持白金触媒等を触媒成分とする公知の構造の
ガス拡散電極を用いればよい。固体高分子電解質膜とし
ても、従来から固体高分子型燃料電池の高分子電解膜と
して知られているカチオン伝導性を示す公知のイオン交
換膜を用いることができ、例えば、ナフイオン、フレミ
オン、アシプレックス等の名称で市販されているものを
使用できる。The integrated regenerating solid polymer fuel cell using the catalyst of the present invention performs the reaction between the solid polymer water electrolysis and the solid polymer fuel cell in the same electrochemical cell, It has a structure in which gas diffusion electrodes are arranged on both sides of a molecular electrolyte membrane as an oxygen electrode and a hydrogen electrode, respectively. In the integrated regeneration type polymer electrolyte fuel cell, as the oxygen electrode, a gas diffusion electrode using the above-mentioned iridium platinum catalyst of the present invention as a catalyst component, and as the hydrogen electrode, a platinum catalyst,
A gas diffusion electrode having a known structure using a carbon-supported platinum catalyst or the like as a catalyst component may be used. As the solid polymer electrolyte membrane, a known ion exchange membrane exhibiting cation conductivity, which is conventionally known as a polymer electrolyte membrane of a polymer electrolyte fuel cell, can be used. For example, naphion, Flemion, Aciplex And those commercially available under such names.
【００３０】[0030]
【発明の効果】本発明のイリジウムと白金の混合触媒
は、酸素発生反応に対する触媒活性と酸素還元反応に対
する触媒活性の両方に優れたものであり、該触媒を用い
たガス拡散電極は、燃料電池の特性を損なうことなく、
水電解電圧を大きく低減することが可能であり、総合的
な触媒活性が優れているために、一体化再生型固体高分
子型燃料電池の特性を大幅に改善することができる。特
に、白金微粒子上にイリジウム化合物の微粒子を担持さ
せた触媒によれば、より一層優れた触媒活性が発揮され
る。The mixed catalyst of iridium and platinum according to the present invention is excellent in both catalytic activity for an oxygen generation reaction and catalytic activity for an oxygen reduction reaction, and a gas diffusion electrode using the catalyst is used in a fuel cell. Without impairing the characteristics of
Since the water electrolysis voltage can be greatly reduced and the overall catalytic activity is excellent, the characteristics of the integrated regenerating solid polymer fuel cell can be greatly improved. In particular, according to a catalyst in which fine particles of an iridium compound are supported on platinum fine particles, more excellent catalytic activity is exhibited.
【００３１】[0031]
【実施例】以下、実施例を挙げて本発明を更に詳細に説
明する。 実施例１ 水酸化ナトリウム６．０ｇを溶解した蒸留水に塩化イリ
ジウム酸を３．３７ｇ投入し、窒素ガスバブリングを行
いながら、４０℃で４時間撹拌することによって、［Ｉ
ｒ（ＯＨ）6］3-を含有する水溶液を得た。この水溶液
を常温に冷却してアスコルビン酸を０．２ｇ加えた後、
窒素ガスバブリングしながら、溶液のｐＨが８になるま
で０．１Ｍ過塩素酸水溶液を徐々に加えた。そのまま一
昼夜以上放置した後、遠心分離によって、水酸化イリジ
ウム水和物を分離した。この沈殿物を蒸留水で十分に洗
浄し、乾燥、粉砕後、さらに、空気中で４００℃で１時
間焼成して、イリジウム化合物を得た。得られたイリジ
ウム化合物は、二次粒子の粒径が約５０〜１００ｎｍで
比表面積が約４０ｍ2／ｇの酸化イリジウムであった。EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. Example 1 3.37 g of iridic acid chloride was added to distilled water in which 6.0 g of sodium hydroxide was dissolved, and the mixture was stirred at 40 ° C. for 4 hours while bubbling with nitrogen gas.
An aqueous solution containing r (OH) 6 ] 3- was obtained. After cooling this aqueous solution to room temperature and adding 0.2 g of ascorbic acid,
With nitrogen gas bubbling, a 0.1 M aqueous solution of perchloric acid was gradually added until the pH of the solution reached 8. After being left as it is for one day or more, iridium hydroxide hydrate was separated by centrifugation. The precipitate was sufficiently washed with distilled water, dried and pulverized, and further calcined at 400 ° C. for 1 hour in the air to obtain an iridium compound. The obtained iridium compound was iridium oxide having a secondary particle size of about 50 to 100 nm and a specific surface area of about 40 m 2 / g.
【００３２】得られたイリジウム化合物を、９倍量（モ
ル比）の高比表面積白金黒（比表面積約２６ｍ2／ｇ、J
ohnson Matthey社製）と十分に混合することによって、
イリジウム化合物と白金黒の混合物からなる触媒微粉末
を得た。The obtained iridium compound was used in an amount of 9 times (molar ratio) high specific surface area platinum black (specific surface area: about 26 m 2 / g, J
Ohnson Matthey)
A fine catalyst powder comprising a mixture of an iridium compound and platinum black was obtained.
【００３３】この様にして得たイリジウムと白金黒の混
合触媒微粉末８５重量％とポリテトラフルオロエチレン
１５重量％からなる混合物を成形し焼成して電極シート
（厚さ０．１ｍｍ、直径３６．５ｍｍ）を作製し、ガス
拡散電極とした。A mixture comprising 85% by weight of the mixed catalyst fine powder of iridium and platinum black thus obtained and 15% by weight of polytetrafluoroethylene was molded and fired, and an electrode sheet (thickness: 0.1 mm; 5 mm) to produce a gas diffusion electrode.
【００３４】このガス拡散電極に、高分子電解質である
ナフィオンの５重量％溶液（Aldrich Chemical社製）を
塗布し、乾燥した。これを酸素極として用い、白金黒７
０重量％とポリテトラフルオロエチレン３０重量％から
なる混合物を成形し焼成して得られたシートを水素極と
して用いて、プロトン導電性高分子電解質（ナフィオン
１１５，デュポン社製）の片面に酸素極を押し当て、も
う一方の面に水素極を押し当てて、１６０℃、７０ｋｇ
ｆ／ｃｍ2にてホットプレスを１分間行って、ガス拡散
電極・プロトン導電体膜の接合体を作製した。 比較例１ 実施例１において酸素極用触媒として用いたイリジウム
化合物と白金黒の混合触媒に代えて、白金黒のみを用い
る以外は、実施例１と同様にして、ガス拡散電極・プロ
トン導電体膜の接合体を作製した。白金黒の使用量は、
実施例１におけるイリジウム化合物と白金黒の合計量と
同量とした。試験例１ 実施例１及び比較例１で作製したガス拡散電極・プロト
ン導電体膜の接合体について、電極面積１０ｃｍ2のセ
ルに組み込み、燃料電池としての運転では水素極に純水
素を流し、酸素極に純酸素を流して、全圧３．０気圧、
８０℃において発電試験を行った。また、水電解装置と
しての運転では、電極に純水を供給しながら、水素極を
電源の負極に接続し、酸素極を電源の正極に接続して通
電し、大気圧下、８０℃で電解試験を行った。A 5% by weight solution of Nafion as a polymer electrolyte (manufactured by Aldrich Chemical Co.) was applied to the gas diffusion electrode and dried. Using this as an oxygen electrode, platinum black 7
Using a sheet obtained by molding and baking a mixture of 0% by weight and polytetrafluoroethylene 30% by weight as a hydrogen electrode, an oxygen electrode was formed on one surface of a proton conductive polymer electrolyte (Nafion 115, manufactured by DuPont). , Press the hydrogen electrode against the other side, 160 ℃, 70kg
Hot pressing was performed at f / cm 2 for 1 minute to produce a gas diffusion electrode-proton conductor membrane assembly. Comparative Example 1 A gas diffusion electrode / proton conductor membrane was prepared in the same manner as in Example 1 except that platinum black alone was used instead of the mixed catalyst of the iridium compound and platinum black used as the catalyst for the oxygen electrode in Example 1. Was prepared. The amount of platinum black used is
The amount was the same as the total amount of the iridium compound and platinum black in Example 1. Test Example 1 The assembly of the gas diffusion electrode and the proton conductor membrane prepared in Example 1 and Comparative Example 1 was incorporated into a cell having an electrode area of 10 cm 2 , and in operation as a fuel cell, pure hydrogen was passed through the hydrogen electrode and oxygen was supplied. Pure oxygen is flowed through the poles and the total pressure is 3.0 atm.
A power generation test was performed at 80 ° C. In operation as a water electrolyzer, while supplying pure water to the electrodes, the hydrogen electrode is connected to the negative electrode of the power supply, the oxygen electrode is connected to the positive electrode of the power supply, and electricity is supplied. The test was performed.
【００３５】実施例１で作製したガス拡散電極・プロト
ン導電体膜の接合体と比較例１で作製したガス拡散電極
・プロトン導電体膜の接合体について、燃料電池及び水
電解装置として作動させた場合の電流電圧特性を図１に
示す。The combined gas diffusion electrode / proton conductor membrane prepared in Example 1 and the combined gas diffusion electrode / proton conductor membrane prepared in Comparative Example 1 were operated as a fuel cell and a water electrolysis apparatus. FIG. 1 shows the current-voltage characteristics in this case.
【００３６】図１より、本発明による白金イリジウム混
合触媒微粉末を用いた実施例１の接合体のガス拡散電極
は、燃料電池作動時の特性を損なわず、水電解電圧を大
きく低減でき、トータルな触媒活性に優れたものであ
り、一体化再生型固体高分子型燃料電池の特性を大きく
改善できることがわかる。 実施例２ 水酸化ナトリウム６．０ｇを溶解した蒸留水に塩化イリ
ジウム酸を３．３７ｇ投入し、窒素ガスバブリングを行
いながら、４０℃で４時間撹拌することによって、［Ｉ
ｒ（ＯＨ）6］3-を含有する水溶液を得た。この水溶液
を常温に冷却後、実施例１で用いたものと同一の高比表
面積白金黒を８．０ｇ加え、十分に分散させた。この白
金黒分散溶液に、アスコルビン酸を０．２ｇ加えた後、
窒素ガスバブリングしながら、溶液のｐＨが８になるま
で０．１Ｍ過塩素酸水溶液を徐々に加えた。そのまま一
昼夜以上放置した後、遠心分離によって、白金−水酸化
イリジウム混合物の沈殿物を分離した。この沈殿物を蒸
留水で十分に洗浄し、乾燥、粉砕後、さらに、空気中で
４００℃で１時間焼成することによって、イリジウム化
合物が担持された白金微粒子を得た。生成物は、粒径約
１００〜５００ｎｍであり、イリジウム：白金（モル
比）＝１：４であった。FIG. 1 shows that the gas diffusion electrode of the joined body of Example 1 using the platinum-iridium mixed catalyst fine powder according to the present invention can greatly reduce the water electrolysis voltage without impairing the characteristics at the time of operating the fuel cell, It can be seen that the properties of the integrated regenerating solid polymer fuel cell can be greatly improved. Example 2 3.37 g of iridic acid chloride was added to distilled water in which 6.0 g of sodium hydroxide was dissolved, and the mixture was stirred at 40 ° C. for 4 hours while bubbling with nitrogen gas to obtain [I
An aqueous solution containing r (OH) 6 ] 3- was obtained. After cooling this aqueous solution to room temperature, 8.0 g of the same high specific surface area platinum black as that used in Example 1 was added and sufficiently dispersed. After adding 0.2 g of ascorbic acid to this platinum black dispersion solution,
With nitrogen gas bubbling, a 0.1 M aqueous solution of perchloric acid was gradually added until the pH of the solution reached 8. After allowing the mixture to stand for one day or more, the precipitate of the platinum-iridium hydroxide mixture was separated by centrifugation. The precipitate was sufficiently washed with distilled water, dried and pulverized, and further calcined at 400 ° C. for 1 hour in the air to obtain platinum fine particles carrying an iridium compound. The product had a particle size of about 100-500 nm and iridium: platinum (molar ratio) = 1: 4.
【００３７】実施例１で用いたイリジウム化合物と白金
黒の混合物からなる触媒微粉末に代えて、上記したイリ
ジウム化合物が担持された白金を用いる以外は、実施例
１と同様にして、ガス拡散電極・プロトン導電体膜の接
合体を作製した。試験例２ 実施例２で作製したガス拡散電極・プロトン導電体膜の
接合体を用いて、上記試験例１と同様にして、燃料電池
及び水電解装置として作動させた場合の電流電圧特性を
求めた。結果を下記図２に示す。図２には、比較例１で
作製したガス拡散電極・プロトン導電体膜の接合体につ
いての試験結果も記載する。A gas diffusion electrode was prepared in the same manner as in Example 1 except that platinum carrying an iridium compound was used instead of the catalyst fine powder comprising a mixture of the iridium compound and platinum black used in Example 1. -A joined body of the proton conductor membrane was produced. Test Example 2 Using the gas diffusion electrode / proton conductor membrane assembly produced in Example 2, the current-voltage characteristics when operating as a fuel cell and a water electrolysis device were determined in the same manner as in Test Example 1 above. Was. The results are shown in FIG. 2 below. FIG. 2 also shows the test results of the gas diffusion electrode / proton conductor membrane assembly produced in Comparative Example 1.
【００３８】図２より、イリジウム化合物が担持された
白金微粒子を用いた実施例２の接合体のガス拡散電極
は、燃料電池作動時の特性を損なわず、水電解電圧を大
きく低減でき、トータルな触媒活性に優れたものであ
り、一体化再生型固体高分子型燃料電池の特性を大きく
改善できることがわかる。FIG. 2 shows that the gas diffusion electrode of the joined body of Example 2 using platinum fine particles carrying an iridium compound can greatly reduce the water electrolysis voltage without impairing the characteristics at the time of operating the fuel cell. It can be seen that the catalyst has excellent catalytic activity and can greatly improve the characteristics of the integrated regeneration type solid polymer fuel cell.
【図１】実施例１及び比較例１で得られた触媒を用いた
一体化再生型固体高分子型燃料電池を燃料電池及び水電
解装置として作動させた場合の電流電圧特性を示すグラ
フ。FIG. 1 is a graph showing current-voltage characteristics when an integrated regeneration type polymer electrolyte fuel cell using the catalysts obtained in Example 1 and Comparative Example 1 is operated as a fuel cell and a water electrolysis device.
【図２】実施例２及び比較例１で得られた触媒を用いた
一体化再生型固体高分子型燃料電池を燃料電池及び水電
解装置として作動させた場合の電流電圧特性を示すグラ
フ。FIG. 2 is a graph showing current-voltage characteristics when an integrated regeneration type polymer electrolyte fuel cell using the catalyst obtained in Example 2 and Comparative Example 1 is operated as a fuel cell and a water electrolysis device.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｈ０１Ｍ 4/92 Ｈ０１Ｍ 4/92 8/10 8/10 (56)参考文献 特開 平10−330979（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B01J 21/00 - 38/74 H01M 4/90 - 4/92 H01M 8/10 ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 7 Identification symbol FI H01M 4/92 H01M 4/92 8/10 8/10 (56) References JP-A-10-330979 (JP, A) (58) ) Field surveyed (Int.Cl. 7 , DB name) B01J 21/00-38/74 H01M 4/90-4/92 H01M 8/10
Claims (10)
リジウム錯イオンを含有する水溶液から、水酸化イリジ
ウム水和物を沈殿析出させた後、含酸素雰囲気中で２０
０〜７００℃で焼成して得られるイリジウム化合物と、
白金微粒子の混合物からなる一体化再生型固体高分子型
燃料電池の酸素極用触媒。1. An iridium hydroxide hydrate is precipitated from an aqueous solution containing an iridium complex ion in which a hydroxide ion is coordinated with iridium, and then precipitated in an oxygen-containing atmosphere.
An iridium compound obtained by firing at 0 to 700 ° C;
A catalyst for an oxygen electrode of an integrated regeneration type polymer electrolyte fuel cell comprising a mixture of platinum fine particles.
リジウム錯イオンを含有する水溶液中に白金微粒子を分
散させた分散液から、水酸化イリジウム水和物を沈殿析
出させた後、含酸素雰囲気中で２００〜７００℃で焼成
して得られる、イリジウム化合物を担持した白金微粒子
からなる一体化再生型固体高分子型燃料電池の酸素極用
触媒。2. An iridium hydroxide hydrate is precipitated from a dispersion of platinum fine particles in an aqueous solution containing an iridium complex ion in which hydroxide ions are coordinated to iridium, and then an oxygen-containing atmosphere is used. A catalyst for an oxygen electrode of an integrated regeneration-type solid polymer fuel cell, comprising platinum particles carrying an iridium compound, obtained by baking at 200 to 700 ° C. in water.
リジウム錯イオンを含有する水溶液が、水酸化アルカリ
水溶液にイリジウム錯体を添加するか、又はイリジウム
錯体を含有する水溶液に水酸化アルカリ化合物を添加し
て得られるものである請求項１又は２に記載の酸素極用
触媒。3. An aqueous solution containing an iridium complex ion in which a hydroxide ion is coordinated with iridium, wherein an iridium complex is added to an aqueous alkali hydroxide solution, or an alkali hydroxide compound is added to an aqueous solution containing an iridium complex. The catalyst for an oxygen electrode according to claim 1 or 2, which is obtained by:
方法が、イリジウム錯イオンを含有する水溶液に酸を添
加する方法である請求項１〜３のいずれかに記載の酸素
極用触媒。4. The catalyst for an oxygen electrode according to claim 1, wherein the method of precipitating and depositing iridium hydroxide hydrate is a method of adding an acid to an aqueous solution containing an iridium complex ion.
を沈殿析出させる請求項１〜４のいずれかに記載の酸素
極用触媒。5. The catalyst for an oxygen electrode according to claim 1, wherein iridium hydroxide hydrate is precipitated in the presence of a reducing agent.
１〜５のいずれかに記載の酸素極用触媒。6. The catalyst for an oxygen electrode according to claim 1, wherein the calcination temperature is 300 to 500 ° C.
いずれかに記載の酸素極用触媒。7. The catalyst for an oxygen electrode according to claim 1, wherein the platinum fine particles are platinum black.
請求項１〜７のいずれかに記載の酸素極用触媒。8. The catalyst for an oxygen electrode according to claim 1, wherein the platinum fine particles are supported on a carrier.
むガス拡散電極である一体化再生型固体高分子型燃料電
池の酸素極。9. An oxygen electrode of an integrated regeneration type polymer electrolyte fuel cell, which is a gas diffusion electrode containing the catalyst according to claim 1.
る一体化再生型固体高分子型燃料電池。10. An integrated regeneration type solid polymer fuel cell comprising the oxygen electrode according to claim 9 as a constituent element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11161827A JP3138732B2 (en) | 1999-06-09 | 1999-06-09 | Catalyst for oxygen electrode of integrated regeneration type polymer electrolyte fuel cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11161827A JP3138732B2 (en) | 1999-06-09 | 1999-06-09 | Catalyst for oxygen electrode of integrated regeneration type polymer electrolyte fuel cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000342965A JP2000342965A (en) | 2000-12-12 |
| JP3138732B2 true JP3138732B2 (en) | 2001-02-26 |
Family
ID=15742679
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11161827A Expired - Lifetime JP3138732B2 (en) | 1999-06-09 | 1999-06-09 | Catalyst for oxygen electrode of integrated regeneration type polymer electrolyte fuel cell |
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| JP (1) | JP3138732B2 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6838205B2 (en) * | 2001-10-10 | 2005-01-04 | Lynntech, Inc. | Bifunctional catalytic electrode |
| US7419732B2 (en) * | 2005-02-11 | 2008-09-02 | Gore Enterprise Holdings, Inc. | Method for reducing degradation in a fuel cell |
| JP4953338B2 (en) * | 2005-06-28 | 2012-06-13 | 独立行政法人産業技術総合研究所 | Solid polymer electrolyte type water electrolysis / fuel cell reversible cell and its oxygen electrode |
| JP5288718B2 (en) * | 2006-03-31 | 2013-09-11 | 日産自動車株式会社 | Electrode catalyst for electrochemical cell, method for producing the same, electrochemical cell, fuel cell and fuel cell |
| JP5261898B2 (en) * | 2006-08-04 | 2013-08-14 | 日産自動車株式会社 | Fuel cell electrode |
| US7608358B2 (en) | 2006-08-25 | 2009-10-27 | Bdf Ip Holdings Ltd. | Fuel cell anode structure for voltage reversal tolerance |
| JP4977911B2 (en) * | 2006-08-28 | 2012-07-18 | アタカ大機株式会社 | Electrode catalyst powder for air electrode of hydrogen-air / solid polymer electrolyte type reversible cell, electrode-electrolyte membrane assembly (MEA) having air electrode and reversible cell using the same |
| JP5224674B2 (en) * | 2006-09-29 | 2013-07-03 | 三洋電機株式会社 | Fuel cell and fuel cell power generation system |
| JP5266749B2 (en) * | 2007-12-21 | 2013-08-21 | 旭硝子株式会社 | Membrane electrode assembly for polymer electrolyte fuel cell and method for producing membrane electrode assembly for polymer electrolyte fuel cell |
| WO2010146475A1 (en) * | 2009-06-18 | 2010-12-23 | University Of The Western Cape | Supported catalysts |
| GB0914562D0 (en) * | 2009-08-20 | 2009-09-30 | Johnson Matthey Plc | Catalyst layer |
| JP7131535B2 (en) * | 2019-12-02 | 2022-09-06 | トヨタ自動車株式会社 | Catalyst layer for fuel cells |
| CN113991126B (en) * | 2021-10-28 | 2023-07-28 | 一汽解放汽车有限公司 | Membrane electrode of gradient proton exchange membrane fuel cell and preparation method and application thereof |
-
1999
- 1999-06-09 JP JP11161827A patent/JP3138732B2/en not_active Expired - Lifetime
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