Method for depositing a metal onto a porous carbon layer

Patent metadata

Field	Value
Publication number	US-9828678-B2
Application number	US-201013497115-A
Country	US
Kind code	B2
Filing date	Sep 20, 2010
Priority date	Sep 21, 2009
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

The invention relates to a method for depositing a metal M 1 onto a carbon layer, as well as to a method for manufacturing an electrode for fuel cells and to a method for manufacturing a fuel cell. The method for depositing a metal M 1 onto a porous carbon layer according to the invention includes a step of depositing said metal M 1 by means of the electrochemical reduction of an electrolytic solution of a salt of the metal M 1 , and, prior to said step of depositing the metal M 1 by means of electrochemical reduction, a step of depositing a metal M 2 by means of chemical reduction using a reducing gas of a salt of the metal M 2 , the thermodynamic equilibrium potential between the ionic form of the salt of M 2 and M 2 , E eq ionic form of the salt of M2/M2 being greater than the thermodynamic equilibrium potential between the ionic form of the salt of M 1 and M 1 , E eq ionic form of the salt of M1/M1 . The invention can be used, in particular, in the field of fuel cells.

First claim

The invention claimed is:

1. A process for preparing an electrode
wherein said process comprises the following steps:
depositing a metal M 2 on a layer made of porous carbon by chemical reduction of a salt of said metal M 2 using a reducing gas such that said metal M 2 is deposited as a discontinuous layer of metal seeds of metal M 2 on said porous carbon layer, and
then depositing a metal M 1 by electrochemical reduction of an electrolytic solution of a salt of the metal M 1 , the thermodynamic equilibrium potential between the ionic form of the salt of M 1 and metal M 1 , E eq ionic form of the salt of M1/M1 , being lower than the thermodynamic equilibrium potential the ionic form of the salt of metal M 2 and M 2 , E eq ionic form of the salt of M2/M2 , so that said metal M 1 is deposited only onto the seeds of metal M 2 ,

so that said M 1 and said metal M 2 are deposited only at sites accessible to gases, and electrons and protons
and said metal M 1 is platinum and said metal M 2 is palladium.

2. The process as claimed in claim 1 , characterized in that the reducing gas comprises hydrogen H 2 or carbon monoxide CO.

3. The process as claimed in claim 1 , characterized in that the reducing gas comprises H 2 +CO.

4. The process as claimed in claim 2 , characterized in that the reducing gas is used as a mixture with a carrier gas chosen from N 2 or Ar or a mixture of these.

5. A process for the manufacture of a fuel cell electrode, the process comprising:
a step of providing a gas diffusion layer;
forming a porous carbon layer on the gas diffusion layer; and
depositing a metal M 1 which is platinum on the layer made of porous carbon according to the process claimed in claim 1 to form a fuel cell electrode.

6. A process for the manufacture of a fuel cell further comprising the step of assembling the fuel cell electrode of claim 5 with a membrane comprising a proton-exchange polymer.

7. The process of claim 1 , further comprising the step of forming a membrane layer on the electrode.

8. The process of claim 1 , wherein the porous carbon layer is deposited on a diffusion layer.

Assignees

• Fouda-Onana Frederic
• Guillet Nicolas
• Commissariat Energie Atomique

Inventors

• Fouda-Onana Frederic
• Guillet Nicolas

Classifications

• C25D5/54

  Electroplating of non-metallic surfaces (C25D7/12 takes precedence) · CPC title

• H01M4/8807

  Gas diffusion layers · CPC title

• H01M4/8853

  Electrodeposition · CPC title

• C23C18/165

  Multilayered product (layered product B32B) · CPC title

• C23C18/1644

  porous substrates · CPC title