Non-noble metal based electro-catalyst compositions for proton exchange membrane based water electrolysis and methods of making
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.
1. 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 comprising two different non-noble metal oxides, each 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 and nickel oxide;
doping the non-noble metal oxide powder with a dopant precursor comprising an element selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, selenium, tellurium and mixtures thereof;
preparing an iridium oxide noble metal precursor in solution;
combining the non-noble metal oxide powder with the iridium oxide 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 a complete oxide alloy and a complete solid solution, and
wherein the electro-catalyst composition is one of the following general formulas:
Ir 1-2x Sn x M x O 2 and Ir 1-2x Sn x M x O 2 :D
wherein M represents Nb, Ta, Ti, W, Mo, Y, Sc, Cu, Zr, Ni, and mixtures thereof, D represents F, Cl, Br, I, S, Se, Te, and mixtures thereof, and x is a value from 10% to 45% based on weight of the composition.
2. The method of claim 1 , further comprising applying the electro-catalyst composition to a substrate to form an anode electrode.
3. 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 comprising two different non-noble metal oxides, each 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 and nickel oxide;
doping the non-noble metal oxide powder with a dopant precursor comprising an element selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, selenium, tellurium and mixtures thereof;
preparing an iridium oxide 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 electro-catalyst composition is one of the following general formulas:
Ir 1-2x Sn x M x O 2 and Ir 1-2x Sn x M x O 2 :D
wherein M represents Nb, Ta, Ti, W, Mo, Y, Sc, Cu, Zr, Ni, and mixtures thereof, D represents F, Cl, Br, I, S, Se, Te, andmixtures thereof, and x is a value from 10% to 45% based on weight of the composition.
4. The method of claim 3 , further comprising applying the electro-catalyst composition to a substrate to form an anode electrode.
5. The method of claim 1 , wherein the surfactant is cetyltrimethylammonium bromide.
6. The method of claim 3 , wherein the solvent is hydrogen peroxide.
7. The method of claim 1 , wherein the dopant precursor is selected from the group consisting of ammonium fluoride, tetraalkyl ammonium fluoride wherein the alkyl group can be ethyl, methyl, butyl or any higher order alkyl group, and mixtures thereof.
8. The method of claim 3 , wherein the dopant precursor is selected from the group consisting of trifluoroacetic acid, any trifluoro organic acid, and mixtures thereof.