Catalyst layer-supporting substrate, method of producing the same and fuel cell
A catalyst layer-supporting substrate includes a substrate and a catalyst layer. The catalyst layer includes a catalyst material and pores. The catalyst layer is formed on the substrate. The catalyst material has a layer or wire shape. A half-value width of a main peak of the catalyst material, as determined from X-ray diffraction spectrum of the catalyst layer, is 1.5° or more. A porosity of the catalyst layer is 30% or more.
1. A method of producing a catalyst layer-supporting substrate, comprising:
forming a laminated body on a substrate by alternately forming first layers and second layers,
the forming further comprising forming the first layers by sputtering or vapor deposition with a catalyst material,
a content of the catalyst material of which per first layer being equivalent to a content of a flat layer with a thickness of 0.3 nm or more and 4 nm or less which consist of the catalyst material solely, and
the forming further comprising forming the second layers by sputtering or vapor deposition with a pore-forming material,
an average thickness of which per second layer being 10 nm or more and 500 nm or less; and
forming pores by removing the pore-forming material in the second layers by solubilization.
2. The method according to claim 1 , wherein the pore-forming material comprises a first inorganic oxide.
3. The method according to claim 2 , wherein the first inorganic oxide is an oxide of at least one element selected from the group consisting of Zr, Ti, Ta, Ru, Si, Al, Sn, Hf, Ge, Ga, In, Ce, Nb, W, Mo, Cr, B and V.
4. The method according to claim 2 , wherein the first inorganic oxide is a mixed inorganic oxide, the mixed inorganic oxide comprises particles of Y oxide comprising at least one element Y selected from the group consisting of W, Mo, Cr, B and V, and a support of X oxide comprising at least one element X selected from the group consisting of Zr, Ti, Ta, Ru, Si, Al, Sn, Hf, Ge, Ga, In, Ce, Nb, W, Mo, Cr, B and V on which the particles are supported.
5. The method according to claim 1 , further comprising:
forming the first layers by sputtering or vapor deposition with a inorganic oxide together with the catalyst material,
a content of the inorganic oxide of which per first layer being equivalent to a content of a flat layer with a thickness of 0.3 nm or more and 20 nm or less which consist of the inorganic oxide solely; and
forming pores by removing the inorganic oxide in the first layers by solubilization.
6. The method according to claim 5 , wherein the inorganic oxide is an oxide of at least one element selected from the group consisting of Zr, Ti, Ta, Ru, Si, Al, Sn, Hf, Ge, Ga, In, Ce, Nb, W, Mo, Cr, B and V.
7. The method according to claim 5 , wherein the inorganic oxide is a mixed inorganic oxide, the mixed inorganic oxide comprises particles of Y oxide comprising at least one element Y selected from the group consisting of W, Mo, Cr, B and V, and a support of X oxide comprising at least one element X selected from the group consisting of Zr, Ti, Ta, Ru, Si, Al, Sn, Hf, Ge, Ga, In, Ce, Nb, W, Mo, Cr, B and V on which the particles are supported.
8. The method according to claim 1 , wherein the laminated body has 5 layers or more and 1000 layers or less respectively of the first and second layers.
9. The method according to claim 1 , wherein the catalyst material is an alloy comprising a noble metal element, and at least one element selected from the group consisting of W, Hf, Si, Mo, Ta, Ti, Zr, Ni, Co, Nb, V, Sn, Al, Cr, Fe and Mn.
10. A catalyst layer-supporting substrate comprising
a substrate; and
catalyst layer formed on the substrate;
wherein
the catalyst layer comprises a catalyst material and pores;
the catalyst material has a layer or wire shape;
a half-value width of a main peak of the catalyst material, as determined from X-ray diffraction spectrum of the catalyst layer, is 1.5° or more; and
a porosity of the catalyst layer is 30% or more.
11. The catalyst layer-supporting substrate according to claim 10 , wherein the catalyst material is an alloy comprising a noble metal element, and at least one element selected from the group consisting of W, Hf, Si, Mo, Ta, Ti, Zr, Ni, Co, Nb, V, Sn, Al, Cr, Fe and Mn.
12. The catalyst layer-supporting substrate according to claim 10 , wherein the catalyst layer comprises an inorganic oxide and the inorganic oxide is particles having an average diameter of 0.5 nm or more and 3 nm or less.
13. The catalyst layer-supporting substrate according to claim 12 , wherein the inorganic oxide is an oxide of at least one element selected from the group consisting of Zr, Ti, Ta, Ru, Si, Al, Sn, Hf, Ge, Ga, In, Ce, Nb, W, Mo, Cr, B and V.
14. The catalyst layer-supporting substrate according to claim 12 , wherein the inorganic oxide is a mixed inorganic oxide, the mixed inorganic oxide comprises particles of Y oxide comprising at least one element Y selected from the group consisting of W, Mo, Cr, B and V, and a support of X oxide comprising at least one element X selected from the group consisting of Zr, Ti, Ta, Ru, Si, Al, Sn, Hf, Ge, Ga, In, Ce, Nb, W, Mo, Cr, B and V on which the particles are supported.
15. A fuel cell comprising an anode catalyst layer, a cathode catalyst layer and a proton-conductive membrane provided between the anode catalyst layer and the cathode catalyst layer, wherein one of the anode catalyst layer and the cathode catalyst layer is a catalyst layer of the catalyst layer-supporting substrate according to claim 10 .