Catalyst for hydrogen generation through steam reforming of hydrocarbons
A catalyst that can be used for the production of hydrogen from hydrocarbon fuels in steam reforming processes contains an active metal of, e.g., at least one of Ir, Pt and Pd, on a catalyst support of, e.g., at least one of monoclinic zirconia and an alkaline-earth metal hexaaluminate. The catalyst exhibits improved activity, stability in both air and reducing atmospheres, and sulfur tolerance.
1. A supported steam reforming catalyst for steam reforming a feed stream containing at least 1 ppm of S comprising:
95 vol % or more of one or more alkaline-earth metal hexaaluminate supports and one or more elements selected from the group consisting of Ir, Pd, and Pt,
wherein the elements are dispersed on the support, and
wherein the catalyst support has a surface area of 6 m 2 /g or more.
2. The supported, steam reforming catalyst according to claim 1 , wherein the catalyst support comprises 98 vol % or more of the alkaline-earth metal hexaaluminate.
3. The supported, steam reforming catalyst according to claim 1 , wherein the catalyst support has a surface area of 12 m 2 /g or more.
4. The supported, steam reforming catalyst according to claim 1 , wherein the catalyst support has a surface area of 18 m 2 /g or more.
5. The supported, steam reforming catalyst according to claim 1 , wherein the alkaline-earth metal hexaaluminate comprises at least one alkaline-earth metal selected from the group consisting of Ca, Sr and Ba.
6. The supported, steam reforming catalyst according to claim 1 , wherein the alkaline-earth metal hexaaluminate comprises BaO 6 Al 2 O 3 .
7. A method of making the supported catalyst of claim 1 , the method comprising
heating at least one precursor oxide in an atmosphere having a partial pressure of O 2 of 0.20 atm or less and containing at least 50 vol % of at least one selected from the group consisting of H 2 , H 2 O and an inert gas; and
producing the catalyst support.
8. The method according to claim 7 , wherein the inert gas is selected from the group consisting of He, Ne, Ar, Kr, Xe and N 2 .
9. The method according to claim 7 , wherein the atmosphere contains at least 50 vol % of N 2 .
10. The method according to claim 7 , wherein the heating is performed at a total pressure of 1 atm.
11. The method according to claim 7 , wherein the heating is performed at a total pressure of less than 1 atm.
12. The method according to claim 7 , wherein the heating is performed at a total pressure of greater than 1 atm.
13. The method according to claim 7 , wherein the precursor oxides are heated in an atmosphere containing a partial pressure of O 2 of 0.10 atm or less.
14. The method according to claim 7 , wherein the heating is at a temperature of no more than 1100° C.
15. The method according to claim 7 , wherein the heating is at a temperature of no more than 950° C.
16. The method according to claim 7 , wherein the heating is at a temperature of no more than 800° C.
17. The method according to claim 7 , wherein the at least one precursor oxide comprises a member of the group consisting of alkaline-earth metal oxides.
18. The method according to claim 7 , the method further comprising heating the at least one precursor oxide in another atmosphere having a partial pressure of O 2 greater than 0.20 atm.
19. The method according to claim 18 , wherein the other atmosphere is air; and the total pressure in the other atmosphere is 1 atm.
20. The method according to claim 18 , wherein the heating in the atmosphere having a partial pressure of O 2 of 0.20 atm or less and the heating in the other atmosphere having a partial pressure of O 2 greater than 0.20 atm are each repeated more than once.
21. A supported, steam reforming catalyst for steam reforming a feed stream containing at least 1 ppm of S comprising
95 vol % or more of a support selected from the group consisting of one or more of alkaline-earth metal hexaaluminate and monoclinic zirconia, and
an active metal comprising Ir,
wherein the Ir is dispersed on the support.
22. The supported, steam reforming catalyst of claim 21 wherein the support comprises an alkaline-earth metal hexaaluminate wherein the alkaline-earth metal is selected from the group consisting of Ca, Sr, and Ba.
23. The supported, steam reforming catalyst of claim 22 wherein the alkaline-earth metal hexaaluminate comprises BaO 6 Al 2 O 3 .
24. The supported, steam reforming catalyst of claim 21 wherein the support comprises monoclinic zirconia.
25. The supported, steam reforming catalyst of claim 21 wherein the active metal dispersed on the support consist essentially of Ir.