Nanostructured Pt
A method of manufacturing a catalyst for a Pt x M y -based PEMFC, M being a transition metal, including the steps of: depositing Pt x M y nanostructures on a support; annealing the nanostructures; depositing a Pt x M y layer at the surface of the nanostructures thus formed; and chemically leaching metal M. It also aims at the catalyst obtained with this method.
1. A method of manufacturing a catalyst for a Pt x M y -based PEMFC, M being a transition metal, comprising the steps of:
depositing a first layer of Pt x M y nanostructures on a support;
annealing the nanostructures;
depositing a second Pt x M y layer at the surface of the nanostructures thus formed; and
producing structured vacancies or cavities, having a size which does not exceed 6 Angströms, at the surface of the second Pt x M y layer, by controlled chemical leaching of metal M.
2. The method of manufacturing a catalyst for a PEMFC of claim 1 , wherein the support is a gas diffusion layer of the PEMFC.
3. The method of manufacturing a catalyst for a PEMFC of claim 2 , wherein the gas diffusion layer has a thickness of 200 micrometers.
4. The method of manufacturing a catalyst for a PEMFC of claim 1 , wherein the support is not a gas diffusion layer of the PEMFC, and wherein after annealing, the nanostructures are transferred onto the gas diffusion layer of the PEMFC.
5. The method of manufacturing a catalyst for a PEMFC of claim 1 , wherein metal M is selected from the group consisting of Ni, Fe, Co, and Cr.
6. The method of manufacturing a catalyst for a PEMFC of claim 5 , wherein the catalyst is formed with Pt 3 Ni.
7. The method of manufacturing a catalyst for a PEMFC of claim 1 , wherein the deposition of nanostructures is performed by cathode sputtering.
8. The method of manufacturing a catalyst for a PEMFC of claim 1 , wherein the anneal is performed at a temperature in a range of 600° C. to 1,200° C.
9. The method of manufacturing a catalyst for a PEMFC of claim 8 , wherein the anneal is performed for a 1-hour duration.
10. The method of manufacturing a catalyst for a PEMFC of claim 1 , wherein the deposition of the Pt x M y layer is performed by MOCVD.
11. The method of manufacturing a catalyst for a PEMFC of claim 10 , wherein the MOCVD is performed by means of organometallic precursors of platinum and of the metal.
12. The method of manufacturing a catalyst for a PEMFC of claim 11 , wherein the MOCVD is performed at a temperature in a range of 200° C. to 400° C.
13. The method of manufacturing a catalyst for a PEMFC of claim 12 , wherein the MOCVD is performed at a temperature of 300° C.
14. The method of manufacturing a catalyst for a PEMFC of claim 1 , wherein the chemical leaching of metal M is performed by immersion in a liquid electrolyte.
15. The method of manufacturing a catalyst for a PEMFC of claim 14 , wherein the liquid electrolyte is H 2 SO 4 .
16. The method of manufacturing a catalyst for a PEMFC of claim 14 , wherein the chemical leaching is performed for 1 hour.
17. A catalyst capable of being obtained by means of the method of claim 1 , said catalyst comprising core/shell nanostructures made of Pt x M y covered with a Pt x M y layer comprising vacancies.
18. The catalyst of claim 17 , wherein the vacancies have a size in the range from 2 to 6 Angströms.
19. A PEMFC-type fuel cell comprising at least at one of its electrodes the catalyst of claim 17 .
20. A method of improving the lifetime of a PEMFC-type fuel cell comprising using as a catalyst, at least at its cathode, the catalyst of claim 17 .
21. A PEMFC-type fuel cell comprising as its cathode the catalyst of claim 17 .