Bimetallic alloy electrocatalysts with multilayered platinum-skin surfaces

Patent metadata

Field	Value
Publication number	US-9246177-B2
Application number	US-201213451852-A
Country	US
Kind code	B2
Filing date	Apr 20, 2012
Priority date	Sep 30, 2011
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

Compositions and methods of preparing a bimetallic alloy having enhanced electrocatalytic properties are provided. The composition comprises a PtNi substrate having a surface layer, a near-surface layer, and an inner layer, where the surface layer comprises a nickel-depleted composition, such that the surface layer comprises a platinum skin having at least one atomic layer of platinum.

First claim

What is claimed is:

1. A method of preparing a bimetallic alloy having enhanced electrocatalytic properties, comprising:
synthesizing a PtNi nanoparticle;
depleting a surface of the PtNi nanoparticle of nickel to create a platinum
skeleton; and
smoothing a surface of the platinum skeleton by annealing and creating the PtNi
nanoparticle with multilayered platinum skin surfaces.

2. The method of claim 1 , wherein the step of depleting a surface of the PtNi nanoparticle is achieved by exposing the PtNi nanoparticle to an acidic environment.

3. The method of claim 2 , wherein the acidic environment comprises a pH of at least 1.0.

4. The method of claim 2 , wherein the step of exposing the PtNi nanoparticle to the acidic environment is performed before the step of annealing the PtNi nanoparticle.

5. The method of claim 2 , further comprising the step of incorporating the PtNi nanoparticle on high surface area carbon by colloidal deposition, forming an electrocatalyst.

6. The method of claim 1 , wherein the platinum skin comprises three or less atomic layers of platinum.

7. The method of claim 1 , wherein the step of annealing is conducted at approximately 400 degrees Celsius.

8. The method of claim 7 , wherein the step of annealing is conducted for at least thirty minutes.

9. A method of preparing a platinum-nickel electrocatalyst, comprising:
synthesizing a PtNi nanoparticle;
depleting a surface of the PtNi nanoparticle of nickel by exposing the PtNi nanoparticle to an acidic environment to create a platinum skeleton surface;
smoothing a surface of the platinum skeleton by annealing to create the PtNi nanoparticle with a multilayered platinum skin; and
incorporating the PtNi nanoparticle on high surface area carbon by colloidal deposition.

10. The method of claim 9 , wherein the synthesizing step further comprises heating the PtNi nanoparticle to remove organic surfacants.

11. The method of claim 9 , wherein the platinum skin comprises 3 or less atomic layers of platinum.

Assignees

• Stamenkovic Vojislav R
• Wang Chao
• Markovic Nenad M
• Uchicago Argonne Llc

Inventors

• Stamenkovic Vojislav R
• Wang Chao
• Markovic Nenad M

Classifications

• H01M4/921 Primary

  Alloys or mixtures with metallic elements · CPC title

• Y02E60/50

  Fuel cells · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• H01M4/926

  on carbon or graphite · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title