Catalyst layer, membrane electrode assembly, and electrochemical cell
A catalyst layer includes a layered structure. The layered structure is laminated with sheet-like unit catalysts and pore layers. The sheet-like unit catalysts have mean thicknesses of 4 to 30 nm. The pore layers are sandwiched between the sheet-like unit catalysts.
1. A catalyst layer comprising a layered structure, which is laminated with sheet-like unit catalyst layers and void layers, each of the sheet-like unit catalyst layers has a mean thickness of 4 to 30 nm, each of the void layers being sandwiched between two of the sheet-like unit catalyst layers, and wherein
the void layer in the structure directly contacts two adjacent sheet-like unit catalyst layers,
the sheet-like unit catalyst layers and the void layers are laminated substantially parallel in a thickness direction of the catalyst layer, and
the sheet-like unit catalyst layers contain at least a noble element.
2. The catalyst layer according to claim 1 , wherein:
the sheet-like unit catalyst layer includes at least three layers laminated in a thickness direction of the sheet-like unit catalyst layer; and
outermost layers of the laminated structure include at least a noble metal and have a composition different from the composition of an inner layer sandwiched between the outermost layers.
3. The catalyst layer according to claim 2 , wherein at least one of the outermost layers has a mean thickness of 0.2 to 5 nm.
4. The catalyst layer according to claim 2 , wherein:
the outermost layers have higher atomic contents of noble metals than the inner layers.
5. The catalyst layer according to claim 1 , wherein:
a number of continuous pores in the sheet-like unit catalyst layer having a diameter of 1 nm or more is 3 or less (including 0) over a length of 20 nm of the sheet-like unit catalyst layer and from a side to the other side in the thickness direction thereof.
6. A membrane electrode assembly, comprising a catalyst layer including a layered structure laminated with sheet-like unit catalyst layers and void layers, each of the sheet-like unit catalyst layers has a mean thickness of 4 to 30 nm, each of the void layers being sandwiched between two of the sheet-like unit catalyst layers, and wherein
the void layer in the structure directly contacts two adjacent sheet-like unit catalyst layers,
the sheet-like unit catalyst layers and the void layers are laminated substantially parallel in a thickness direction of the catalyst layer, and
the sheet-like unit catalyst layers contain at least a noble element.
7. An electrochemical cell, comprising the membrane electrode assembly according to claim 6 .
8. A catalyst layer comprising a layered structure, which is laminated with sheet-like unit catalyst layers and void layers, each of the sheet-like unit catalyst layers has a mean thickness of 4 to 30 nm, each of the void layers being sandwiched between two of the sheet-like unit catalyst layers, and wherein
the void layer in the structure directly contacts two adjacent sheet-like unit catalyst layers in a cross section,
the sheet-like unit catalyst layers and the void layers are laminated substantially parallel in a thickness direction of the catalyst layer, and
the sheet-like unit catalyst layers contain at least a noble element.
9. The catalyst layer according to claim 8 , wherein:
the sheet-like unit catalyst layer includes at least three layers laminated in a thickness direction of the sheet-like unit catalyst layer; and
outermost layers of the laminated structure include at least a noble metal and have a composition different from the composition of an inner layer sandwiched between the outermost layers.
10. The catalyst layer according to claim 9 , wherein at least one of the outermost layers has a mean thickness of 0.2 to 5 nm.
11. The catalyst layer according to claim 9 , wherein:
the outermost layers have higher atomic contents of noble metals than the inner layers.
12. The catalyst layer according to claim 8 , wherein:
a number of continuous pores in the sheet-like unit catalyst layer having a diameter of 1 nm or more is 3 or less (including 0) over a length of 20 nm of the sheet-like unit catalyst layer and from a side to the other side in the thickness direction thereof.
13. A catalyst layer comprising a layered structure, which is laminated with sheet-like unit catalyst layers and void layers, each of the sheet-like unit catalyst layers has a mean thickness of 4 to 30 nm, each of the void layers being sandwiched between two of the sheet-like unit catalyst layers, and wherein
the sheet-like unit catalyst layers sandwiching the adjacent void layer are connected with each other,
the sheet-like unit catalyst layers and the void layers are laminated substantially parallel in a thickness direction of the catalyst layer, and
the sheet-like unit catalyst layers contain at least a noble element.
14. The catalyst layer according to claim 13 , wherein:
the sheet-like unit catalyst layer includes at least three layers laminated in a thickness direction of the sheet-like unit catalyst layer; and
outermost layers of the laminated structure include at least a noble metal and have a composition different from the composition of an inner layer sandwiched between the outermost layers.
15. The catalyst layer according to claim 14 , wherein at least one of the outermost layers has a mean thickness of 0.2 to 5 nm.
16. The catalyst layer according to claim 14 , wherein:
the outermost layers have higher atomic contents of noble metals than the inner layers.
17. The catalyst layer according to claim 13 , wherein:
a number of continuous pores in the sheet-like unit catalyst layer having a diameter of 1 nm or more is 3 or less (including 0) over a length of 20 nm of the sheet-like unit catalyst layer and from a side to the other side in the thickness direction thereof.
18. A catalyst layer comprising a layered structure, which is laminated with sheet-like unit catalyst layers and void layers, each of the sheet-like unit catalyst layers has a mean thickness of 4 to 30 nm, each of the void layers being sandwiched between two of the sheet-like unit catalyst layers, and wherein
the void layer in the structure directly contacts two adjacent sheet-like unit catalyst layers,
the sheet-like unit catalyst layers and the void layers are laminated and have a portion substantially parallel in a thickness direction of the catalyst layer, and
the sheet-like unit catalyst layers contain at least a noble element.
19. The catalyst layer according to claim 18 , wherein:
the sheet-like unit catalyst layer includes at least three layers laminated in a thickness direction of the sheet-like unit catalyst layer; and
outermost layers of the laminated structure include at least a noble metal and have a composition different from the composition of an inner layer sandwiched between the outermost layers.
20. The catalyst layer according to claim 18 , wherein at least one of the outermost layers has a mean thickness of 0.2 to 5 nm.
21. The catalyst layer according to claim 18 , wherein:
a number of continuous pores in the sheet-like unit catalyst layer having a diameter of 1 nm or more is 3 or less (including 0) over a length of 20 nm of the sheet-like unit catalyst layer and from a side to the other side in the thickness direction thereof.
22. The catalyst layer according to claim 18 , wherein:
the outermost layers have higher atomic contents of noble metals than the inner layers.