NON-NOBLE METAL BASED ELECTRO-CATALYST COMPOSITIONS FOR PROTON EXCHANGE MEMBRANE BASED WATER ELECTROLYSIS AND METHODS OF MAKING

• US 20170233879A1
• Filed: 12/21/2016
• Published: 08/17/2017
• Est. Priority Date: 08/08/2012
• Status: Active Grant

• Current Assignee: University of Pittsburgh of The Commonwealth System of Higher Education
• Original Assignee: University of Pittsburgh of The Commonwealth System of Higher Education
• Inventors: KADAKIA, KARAN SANDEEP, HANUMANTHA, PRASHANTH JAMPANI, KUMTA, PRASHANT N., DATTA, MONI KANCHAN, VELIKOKHATNYI, OLEG
• Granted Patent: US 10,041,179 B2
• Time in Patent Office: Days
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C25B 1/04 by electrolysis of water
• CPC Class Codes: C25B 11/051 Electrodes formed of electrocatalysts on a substrate or carrier
• CPC Class Codes: C25B 11/093 at least one noble metal or noble metal oxide and at least one non-noble metal oxide
• CPC Class Codes: C25B 9/73 of the filter-press type
• CPC Class Codes: H01M 4/881 Electrolytic membranes
• CPC Class Codes: H01M 4/8828 Coating with slurry or ink
• CPC Class Codes: H01M 4/9016 Oxides, hydroxides or oxygenated metallic salts
• CPC Class Codes: H01M 4/9075 Catalytic material supported on carriers, e.g. powder carriers H01M4/8807, H01M4/881, H01M4/8814, H01M4/925 take precedence
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

The invention provides electro-catalyst compositions for an anode electrode of an acid mediated proton exchange membrane-based water electrolysis system. The compositions include a noble metal component selected from the group consisting of iridium oxide, ruthenium oxide, rhenium oxide and mixtures thereof, and a non-noble metal component selected from the group consisting of tantalum oxide, tin oxide, niobium oxide, titanium oxide, tungsten oxide, molybdenum oxide, yttrium oxide, scandium oxide, cooper oxide, zirconium oxide, nickel oxide and mixtures thereof. Further, the non-noble metal component can include a dopant. The dopant can be at least one element selected from Groups III, V, VI and VII of the Periodic Table. The compositions can be prepared using any solution based methods involving a surfactant approach or a sol gel approach. Further, the compositions are prepared using noble metal and non-noble metal precursors. Furthermore, a thin film containing the compositions can be deposited onto a substrate to form the anode electrode.

Claims

1. An electro-catalyst composition for an anode electrode of a proton exchange membrane-based water electrolysis system, comprising:

a noble metal component selected from the group consisting of iridium oxide, ruthenium oxide, rhenium oxide and mixtures thereof; and

a non-noble metal component selected from the group consisting of tantalum oxide, tin oxide, niobium oxide, titanium oxide, tungsten oxide, molybdenum oxide, yttrium oxide, scandium oxide, copper oxide, zirconium oxide, nickel oxide and mixtures thereof,

wherein the electro-catalyst composition is in a form selected from an oxide alloy and a solid solution, and

wherein the electro-catalyst composition exhibits an electronic structure that mimics a noble metal oxide electro-catalyst composition absent of a non-noble metal.

2. The composition of claim 1, wherein the non-noble metal component further comprises a dopant selected from the group consisting of at least one element from Groups III, V, VI and VII of the Periodic Table.

3. The composition of claim 1, wherein the dopant is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, selenium, tellurium and mixtures thereof.

4. The composition of claim 2, wherein the dopant is present in an amount from greater than 0 to 20 weight percent based on weight of the composition.

5. The composition of claim 1, wherein each of the noble metal component and the non-noble metal component is independently present in an amount of from greater than zero to 99 weight percent based on weight of the composition.

6. The composition of claim 1, wherein the non-noble metal component and the noble metal component form a complete solid solution.

7. The composition of claim 1, wherein the composition is in the form of a nanocrystalline thin film, nanorods, nanoplates, nanoshells, nanoflakes, nanorods, nanospheres, or any nano-scale morphology coated on a current collector substrate.

18. The composition of claim 1, wherein the electro-catalyst composition is of one of the following general formulas:

N_xM_1-xO₂ and N_xM_1-xO₂;

D,

wherein N represents iridium, ruthenium, rhenium and mixtures thereof, M represents Sn, Nb, Ta, Ti, W, Mo, Y, Sc, Cu, Zr, Ni and mixtures thereof, D represents at least one element from Groups III, V, VI or VII of the Periodic Table, and x is a value greater than 0% to 99% based on weight of the composition.

19. The composition of claim 1, wherein the electro-catalyst composition is one of the following general formulas:

Ir_1-x-ySn_xM_yO₂ and Ir_1-x-ySn_xM_yO₂;

D

wherein M represents tantalum, niobium, titanium, tungsten, molybdenum, yttrium, scandium, copper, zirconium, nickel, or mixtures thereof. D represents at least one element selected from Group III, V, VI, or VII of the Periodic Table, each of x and y is independently a value from greater than zero to 99% (i.e., greater than 0 to 0.99), and x+y is less than or equal to 99% (i.e., 0.99) based on weight of the composition.

20. The composition of claim 1, wherein the electro-catalyst composition is of one of the following general formulas:

Ir_1-2xSn_xM_xO₂ and Ir_1-2xSn_xM_xO₂;

D,

wherein M represents Nb, Ta, Ti, W, Mo, Y, Sc, Cu, Zr, Ni, and mixtures thereof, D represents an at least one element from Groups III, V, VI or VII of the Periodic Table, and x is a value greater than 0 and 49.5% (i.e., greater than 0 to 0.495) based on weight of the composition.

8. A method for preparing an electro-catalyst composition for an anode electrode in a proton exchange membrane-based water electrolysis system, comprising:

preparing a surfactant in solution;

adding an ammonium compound to the surfactant in solution to form a first mixture;

preparing a non-noble metal precursor in solution;

combining the first mixture and the non-noble metal precursor in solution to form a first precipitate;

separating and drying the first precipitate to form a non-noble metal oxide powder;

preparing a noble metal precursor in solution;

combining the non-noble metal oxide powder with the noble metal precursor in solution to form a second mixture; and

separating and drying a precipitate from the second mixture to form the electro-catalyst composition,

wherein the resulting electro-catalyst composition is in a form selected from an oxide alloy and a solid solution, and

wherein the resulting electro-catalyst composition exhibits an electronic structure that mimics a noble metal oxide electro-catalyst composition absent of a non-noble metal.

9. The method of claim 9, further comprising doping the non-noble metal oxide powder with a dopant precursor selected from the group consisting of at least one element from Groups III, V, VI and VII of the Periodic Table to form a doped non-noble metal oxide powder.

10. The method of claim 9, further comprising applying the electro-catalyst composition to a substrate to form an anode electrode.

14. The method of claim 9, wherein the surfactant is cetyltrimethylammonium bromide.

16. The method of claim 10, wherein the dopant precursor is selected from the group consisting of ammonium fluoride, tetralkyl ammonium fluoride wherein the alkyl group can be ethyl, methyl, butyl or any higher order alkyl group, and mixtures thereof.

11. A method for preparing an electro-catalyst composition for an anode electrode in a proton exchange membrane-based water electrolysis system, comprising:

obtaining an ammonium compound;

preparing a non-noble metal precursor in solution;

combining the ammonium compound and the non-noble metal precursor in solution to form a first precipitate;

separating the first precipitate;

dispersing the first precipitate in solvent to form a sol gel;

drying the sol gel to form a non-noble metal oxide powder;

preparing a noble metal precursor in solution;

combining the non-noble metal oxide powder with the noble metal precursor in solution to form a second mixture; and

separating and drying a precipitate from the second mixture to form the electro-catalyst composition.

12. The method of claim 12, further comprising doping the non-noble metal oxide powder with a dopant precursor selected from the group consisting of at least one element from Groups III, V, VI and VII of the Periodic Table to form a doped non-noble metal oxide powder.

13. The method of claim 12, further comprising applying the electro-catalyst composition to a substrate to form an anode electrode.

15. The method of claim 12, wherein the reactant is hydrogen peroxide.

17. The method of claim 13, wherein the dopant precursor is selected from the group consisting of trifluoroacetic acid, any trifluoro organic acid, and mixtures thereof.