Catalyst particle, and electrode catalyst, electrolyte membrane-electrode assembly, and fuel cell using the same

Patent metadata

Field	Value
Publication number	US-2016197358-A1
Application number	US-201414910872-A
Country	US
Kind code	A1
Filing date	Aug 6, 2014
Priority date	Aug 9, 2013
Publication date	Jul 7, 2016
Grant date	—

Abstract

An object is to provide a catalyst particle that can exhibit high activity. The catalyst particle is an alloy particle formed of platinum atom and a non-platinum metal atom, wherein (i) the alloy particle has an L1 2 structure as an internal structure and has an extent of ordering of L1 2 structure in the range of 30 to 100%, (ii) the alloy particle has an LP ratio calculated by CO stripping method of 10% or more, and (iii) the alloy particle has a d N /d A ratio in the range of 0.4 to 1.0.

First claim

1 . A catalyst particle which is an alloy particle formed of platinum atom and a non-platinum metal atom, wherein
(i) the alloy particle has an L1 2 structure as an internal structure and has an extent of ordering of L1 2 structure in the range of 30 to 100%, (ii) the alloy particle has an LP ratio calculated by CO stripping method of 10% or more, and (iii) the alloy particle has a d N /d A ratio in the range of 0.4 to 1.0.

2 . The catalyst particle according to claim 1 , wherein the extent of ordering is in the range of 47 to 95%.

3 . The catalyst particle according to claim 1 , wherein the non-platinum metal atom is a transition metal atom.

4 . The catalyst particle according to claim 3 , wherein the transition metal atom is selected from the group consisting of vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), and zirconium (Zr).

5 . The catalyst particle according to claim 4 , wherein the transition metal atom is cobalt (Co).

6 . A method of producing a catalyst particle, comprising:
(1) preparing a mixed solution containing a platinum precursor and a non-platinum metal precursor; (2) adding a reducing agent to the mixed solution, and reducing the platinum precursor and the non-platinum metal precursor simultaneously, thereby obtaining a catalyst precursor particle-containing liquid; (3) adding a carbon carrier to the catalyst precursor particle-containing liquid, thereby obtaining a catalyst precursor particle-supported carrier, the carbon carrier having at least one or more functional groups selected from the group consisting of a lactone group, a hydroxyl group, an ether group, and a carbonyl group formed on the surface thereof in a total amount of 0.5 μmol/m 2 or more; and (4) subjecting the catalyst precursor particle-supported carrier to heat-treatment.

7 . The method according to claim 6 , wherein the carbon carrier is obtained by contacting a carbon material with an acidic solution and then subjecting the carbon material to heat-treatment.

8 . The method according to claim 6 , wherein a ratio of a non-platinum metal contained in the non-platinum metal precursor to platinum contained in the platinum precursor (molar ratio of the non-platinum metal to the platinum) is in the range of 0.4 to 20.

9 . The method according to claim 6 , wherein the heat-treatment of the catalyst precursor particle-supported carrier is performed:
(a) at a temperature in the range of 350 to 450° C. for a time exceeding 120 minutes under a reducing gas atmosphere or an inert gas atmosphere; (b) at a temperature exceeding 450° C. but 750° C. or lower for 10 minutes or more under a reducing gas atmosphere or an inert gas atmosphere; (c) at a temperature exceeding 750° C. for a time of 10 to 120 minutes under an inert gas atmosphere; or (d) at a temperature exceeding 750° C. for a time of 10 to 45 minutes under a reducing gas atmosphere.

10 . An electrolyte membrane-electrode assembly comprising the catalyst particle set forth in claim 1 .

11 . A fuel cell comprising the electrolyte membrane-electrode assembly set forth in to claim 10 .

12 . A catalyst particle produced by the method set forth in claim 6 .

Assignees

• Nissan Motor

Inventors

• Arihara Kazuki
• Tanaka Hiroyuki
• Mitsumoto Hisashi
• Kaito Takahiro
• Sugawara Seiho
• Ohwaki Tsukuru

Classifications

• H01M8/1004

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title

• H01M4/926 Primary

  on carbon or graphite · CPC title

• H01M4/8882

  Heat treatment, e.g. drying, baking · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• C22C5/04

  Alloys based on a platinum group metal · CPC title