Caged Nanoparticle Electrocatalyst with High Stability and Gas Transport Property

Patent metadata

Field	Value
Publication number	US-2016211530-A1
Application number	US-201614991167-A
Country	US
Kind code	A1
Filing date	Jan 8, 2016
Priority date	Jan 15, 2015
Publication date	Jul 21, 2016
Grant date	—

Abstract

A method for forming a caged electrocatalyst particles for fuel cell applications include a step of forming modified particles having a porous SiO 2 shell on a surface of platinum-containing particles. The modified particles are subjected to acid treatment or electrochemical oxidation to remove a portion of the platinum-containing particle thereby creating caged electrocatalyst particles having a gap between the platinum-containing particles and their SiO 2 shell.

First claim

What is claimed is:

1 . A caged electrocatalyst particle comprising:
a metal oxide shell defining a central cavity, the metal oxide shell having an average diameter less than 100 nm; a platinum group metal-containing particle disposed within the cavity.

2 . The caged electrocatalyst of claim 1 wherein the metal oxide layer includes a component selected from the group consisting of silicon oxide, aluminum oxide, and combinations thereof.

3 . The caged electrocatalyst of claim 1 wherein the metal oxide shell defines a gap between the metal oxide shell and the platinum group metal-containing particle.

4 . The caged electrocatalyst of claim 1 wherein the platinum group metal-containing particle is a platinum alloy.

5 . The caged electrocatalyst of claim 1 wherein the platinum group metal-containing particle includes a platinum-group metal.

6 . The caged electrocatalyst of claim 5 wherein platinum group metal-containing particle includes platinum.

7 . The caged electrocatalyst of claim 5 wherein platinum group metal-containing particle further includes a non-noble metal.

8 . The caged electrocatalyst of claim 5 wherein the non-noble metal is Fe, Ni, Co, Cu, or combinations thereof.

9 . A method for forming caged electrocatalyst particles for a fuel cell catalyst layers, the method comprising:
a) reacting platinum group metal-containing particles with an absorption solution, the absorption solution including a compound having formula 1 and a compound having formula 2:
X 1 -R 2 -M-(OR 1 ) n   1

X 2 -R 3 -Y   2

wherein:
X 1 and X 2 are each independently SH or NH 2 ;
R 1 are each independently C 1-6 alkyl;
M is a metal that can form a metal oxide.
Y is a moiety that does not react with the compound having formula 1;
n is an integer represent the number of OR 1 groups attached to M;
R 2 , R 3 are each independently is a C 1-6 alkylenyl;
b) allowing M in the compound having formula 1 to hydrolyze to form modified particles having a porous metal oxide shell on a surface of the platinum group metal-containing particle; and
c) subjecting the modified particles to acid treatment or electrochemical oxidation to remove a portion of the platinum-containing particles thereby creating caged electrocatalyst particles having a gap between the platinum group metal-containing particles and their metal oxide shell.

10 . The method of claim 9 wherein M is Si, Al, Ti, or W.

11 . The method of claim 9 wherein when M is Si or Ti, n is 3 and when M is Al, n is 2.

12 . The method of claim 9 wherein M is Si.

13 . The method of claim 9 wherein Y is CO 2 H, CH 3 , NH 2 , or halo.

14 . The method of claim 9 wherein X 1 and X 2 are each SH.

15 . The method of claim 9 wherein the platinum group metal-containing particles and the caged electrocatalyst particles are each nanoparticles.

16 . The method of claim 9 wherein the platinum group metal-containing particles are platinum alloy particles.

17 . The method of claim 16 wherein the platinum group metal-containing particles are PtNi 3 particles, PtCo particles, PtCo 3 particles, PtCu 3 particles, PtFe 3 particles, PdNi 3 particles, PdFe 3 particles, or PdRhFe 3 particles.

18 . The method of claim 17 wherein in step c) a portion of the Ni is removed from PtNi 3 particles.

19 . The method of claim 9 wherein the compound having formula 1 is mercaptopropyltrimethoxysilane (MPTS).

20 . The method of claim 9 wherein the compound having formula 2 is and mercaptopropionic acid (MPA).

Assignees

• Gm Global Tech Operations Inc

Inventors

• Kongkanand Anusorn

Classifications

• H01M4/9016 Primary

  Oxides, hydroxides or oxygenated metallic salts · CPC title

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M4/921

  Alloys or mixtures with metallic elements · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M4/92 Primary

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