The invention claimed is:
1. A catalyst structure comprising:
a support that has a porous structure and comprises a zeolite-type compound; and
a functional material present in the support,
the functional material comprising:
a first metal element selected from the group consisting of cobalt (Co), nickel (Ni), iron (Fe), and ruthenium (Ru); and
a second metal element selected from the group consisting of metal elements belonging to Groups 1, 2, 4, 7, and 12 of periodic table, wherein
the support has channels communicating with one another,
the functional material is present at least in the channels of the support,
the channels have any one of a one-dimensional pore a two-dimensional pore, a three-dimensional pore of a framework structure of the zeolite-type compound, and an enlarged pore portion which is not defined by the framework structure of the zeolite-type compound and has a diameter greater than any one of the one-dimensional pore, the two-dimensional pore and the three-dimensional pore,
the enlarged pore portion has a greater diameter than the functional material,
the functional material has a diameter greater than any one of the one-dimensional pore, the two-dimensional pore and the three-dimensional pore,
the functional material includes metal oxide nanoparticles, and
the framework structure of the zeolite-type compound is selected from the group consisting of FAU type, MTW type, MFI type, FER type, LTA type, MWW type, MOR type, LTL type, and BEA type.
2. The catalyst structure according to claim 1 , wherein the second element is at least one metal element selected from the group consisting of potassium (K), magnesium (Mg), titanium (Ti), zirconium (Zr), manganese (Mn), and zinc (Zn).
3. The catalyst structure according to claim 1 , wherein a mass ratio of a content of the second element to a content of the first element is from 0.01 to 2.00.
4. The catalyst structure according to claim 1 , wherein a total content of the first element is 0.5% by mass or more with respect to the mass of the catalyst structure.
5. The catalyst structure according to claim 1 , wherein a total content of the second element is 5% by mass or less with respect to the mass of the catalyst structure.
6. The catalyst structure according to claim 1 , wherein a content of the second element is lower than a content of the first element.
7. The catalyst structure according to claim 1 , wherein the functional material is in the form of metal oxide particles comprising one or both of an oxide of the first element and an oxide of the second element.
8. The catalyst structure according to claim 1 , wherein the functional material is in the form of metal particles comprising one or both of the first element and the second element.
9. The catalyst structure according to claim 8 , wherein the metal particles comprise one or both of: particles of an alloy comprising the first element and the second element; and at least two types of single metal particles comprising particles of the first element and particles of the second element.
10. The catalyst structure according to claim 1 , wherein;
the enlarged pore portion is different from all of the one-, two-, and three-dimensional pores, and
the functional material is present at least in the enlarged pore portion.
11. The catalyst structure according to claim 10 , wherein the enlarged pore portion connects a plurality of pores constituting one of the one-, two-, and three-dimensional pores.
12. The catalyst structure according to claim 10 , wherein the functional material has an average particle size equal to or smaller than an inner diameter of the enlarged pore portion.
13. The catalyst structure according to claim 10 , wherein the enlarged pore portion has an inner diameter of 0.5 nm to 50 nm.
14. The catalyst structure according to claim 1 , wherein the functional material has an average particle size larger than an average inner diameter of the channels.
15. The catalyst structure according to claim 1 , wherein the functional material has an average particle size of 0.08 nm to 30 nm.
16. The catalyst structure according to claim 1 , wherein a ratio of an average particle size of the functional material to an average inner diameter of the channels is from 0.05 to 300.
17. The catalyst structure according to claim 1 , wherein the channels have an average inner diameter of 0.1 nm to 1.5 nm.
18. The catalyst structure according to claim 1 , further comprising at least one additional functional material held on an outer surface of the support.
19. The catalyst structure according to claim 18 , wherein the additional functional material comprises one or more metals selected from the group consisting of cobalt (Co), nickel (Ni), iron (Fe), ruthenium (Ru), and an alloy thereof.
20. The catalyst structure according to claim 18 , wherein the additional functional material comprises one or more metals selected from the group consisting of elements belonging to Groups 1, 2, 4, 7, and 12 of periodic table, and an alloy thereof.