Catalyst particles for fuel cells and method for producing same

Patent metadata

Field	Value
Publication number	US-2016013494-A1
Application number	US-201414769988-A
Country	US
Kind code	A1
Filing date	Jan 22, 2014
Priority date	Feb 25, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

A catalyst particle ( 1 ) for a fuel cell according to the present invention includes: a metal particle ( 2 ) composed of either one of metal other than noble metal and an alloy of the metal other than the noble metal and the noble metal; and a noble metal layer ( 3 ) that is provided on a surface of the metal particle and has a thickness of 1 nm to 3.2 nm. By the fact that the catalyst particle for a fuel cell has such a configuration, the catalyst particle can enhance catalytic activity while reducing an amount of the noble metal. The catalyst particle ( 1 ) for a fuel cell according to the present invention can enhance the catalytic activity while reducing the amount of the noble metal.

First claim

1 - 14 . (canceled)

15 . A catalyst particle for a fuel cell, the catalyst particle comprising:
a metal particle composed of either one of metal other than noble metal and an alloy of the metal other than the noble metal and the noble metal, and having a particle diameter of 2 nm to 5.5 nm; and a noble metal layer that is provided on a surface of the metal particle, consists of platinum and has a thickness of 1 nm to 3.2 nm, wherein the noble metal layer covers at least 60% or more of the surface of the metal particle.

16 . The catalyst particle for a fuel cell according to claim 15 ,
wherein the noble metal in the metal particle is at least one selected from the group consisting of platinum, palladium, gold, iridium, ruthenium and silver, and the metal other than the noble metal in the metal particle is at least one selected from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum and tantalum.

17 . A catalyst for a fuel cell, the catalyst comprising:
the catalyst particle for a fuel cell according to claim 15 ; and a conductive carrier that carries the catalyst particle for a fuel cell thereon.

18 . A method for producing a catalyst particle for a fuel cell, the method comprising the steps of:
preparing a precursor solution having a concentration of metal other, than the noble metal of 2.5 mM or less by dispersing salt of the metal other than noble metal or a complex of the metal other than the noble metal into a solvent, and thereafter, preparing a metal particle dispersion by adding a reducing agent to the precursor solution; and forming a noble metal layer on a surface of a metal particle by adding noble metal salt or a noble metal complex to the metal particle dispersion.

19 . The method for producing a catalyst particle for a fuel cell according to claim 18 ,
wherein the noble metal salt or the noble metal complex added to the metal particle dispersion in the step of the forming the noble metal layer contains at least one selected from the group consisting of platinum, palladium, gold, iridium, ruthenium and silver.

20 . The method for producing a catalyst particle for a fuel cell according to claim 18 ,
wherein a noble metal element composing the noble metal salt or the noble metal complex added to the metal particle dispersion in the step of the forming the noble metal layer consists of platinum.

21 . The method for producing a catalyst particle for a fuel cell according to claim 18 ,
wherein the salt of the metal other than the noble metal or the complex of the metal other than the noble metal dispersed in the solvent in the step of the preparing the precursor solution contains at least one selected from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum and tantalum.

22 . The method for producing a catalyst particle for a fuel cell according to claim 18 , wherein a ratio ([number of moles of metal other than noble metal]/[number of moles of noble metal]) of a number of moles of the metal other than the noble metal to a number of moles of the noble metal in the metal particle dispersion is 3.2 to 11.

Assignees

• Nissan Motor

Inventors

• Arihara Kazuki
• Tanaka Hiroyuki

Classifications

• H01M4/92 Primary

  Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) · CPC title

• C23C18/44

  using reducing agents · CPC title

• C23C18/1637

  metallic substrate · CPC title

• H01M4/8842

  Coating using a catalyst salt precursor in solution followed by evaporation and reduction of the precursor · CPC title

• H01M4/9058

  of noble metals or noble-metal based alloys · CPC title