Supported metal catalyst with improved thermal stability
Catalytic systems are provided that include a metallic catalyst attached to a ceramic support that has alumina as a principal ingredient. The ceramic support is doped with an adhesive agent so that the surface of the support includes the adhesive agent. The adhesive agent is designed to form an open-shell electronic structure at the interface between the metallic catalyst and the support. The open-shell structure promotes extended useful catalyst lifetimes. The adhesive agents are early transition metals that include titanium, zirconium, scandium, hafnium, lanthanum and yttrium. Doping of the ceramic support surface with the adhesive agent also increases the adhesion between the ceramic support and metallic monoliths to which the ceramic support may be attached.
1. A catalytic system comprising:
a ceramic support comprising alumina, said ceramic support including a surface that comprises a monolayer of an adhesive agent provided on said surface, said adhesive agent comprising at least one of titanium, zirconium, scandium, hafnium, lanthanum, and yttrium metals; and
a plurality of metal catalyst particles attached to the surface of said ceramic support wherein said monolayer of the adhesive agent provides increased adhesion between the ceramic support and the plurality of metal catalyst particles.
2. A catalytic system according to claim 1 wherein said ceramic support is in the shape of a particle.
3. A catalytic system according to claim 1 wherein said metal catalyst particles are selected from the group consisting of nickel, palladium and platinum.
4. A catalytic system according to claim 1 wherein said adhesive agent is in the form of a ¼ to ¾ to monolayer on said surface.
5. A catalytic system according to claim 1 wherein said adhesive agent is applied to the surface of the ceramic support as reduced metals.
6. A catalytic system according to claim 1 wherein two or more adhesive agents are present at the surface of said support.
7. A catalytic system according to claim 1 wherein said adhesive agent is in the form of a ½ monolayer on said surface.
8. A catalytic system according to claim 1 wherein the adhesive agent is applied to the surface of the ceramic support as suboxides.
9. A catalytic system according to claim 1 wherein the ceramic support further comprising a second surface on which a monolayer of said adhesive agent is provided; and
the catalytic system further comprising a monolith attached to said second surface of the ceramic support.
10. A catalytic system according to claim 9 , the monolith having a surface comprising metal on which said second surface of the ceramic support is attached.
11. A catalytic system according to claim 9 wherein the monolayer of the adhesive agent on said second surface of the ceramic support is in the form of a ¼ to ¾ monolayer.
12. A catalytic system according to claim 9 wherein the monolayer of the adhesive agent on said second surface of the ceramic support is in the form of a ½ monolayer.
13. A catalytic system according to claim 9 wherein the adhesive agent is applied to the second surface of the ceramic support as reduced metals.
14. A catalytic system according to claim 9 wherein the adhesive agent is applied to the second surface of the ceramic support as suboxides.
15. A method for making a catalytic system comprising the steps of:
providing a ceramic support comprising alumina, said ceramic support including a surface that is capable of supporting a monolayer of an adhesive agent provided on said surface;
treating said surface with an adhesive agent to provide a modified surface that is doped with a monolayer of said adhesive agent, said adhesive agent comprising at least one of titanium, zirconium, scandium, hafnium, lanthanum, and yttrium metals; and
attaching a plurality of metal catalyst particles to the modified surface of said ceramic support whereby said monolayer of the adhesive agent provides increased adhesion between the ceramic support and the plurality of metal catalyst particles.
16. The method of claim 15 wherein said ceramic support is in the shape of a particle.
17. The method of claim 15 wherein said metal catalyst particles are selected from the group consisting of nickel, palladium and platinum.
18. The method of claim 15 wherein said adhesive agent is in the form of 1 / 4 to 3 / 4 monolayer on said surface.
19. The method of claim 15 wherein two or more adhesive agents are present at the surface of said support.
20. The method of claim 15 that includes the additional step of attaching said supported metal catalyst to a metallic monolith structure.
21. The method of claim 16 that includes the additional step of attaching said supported metal catalyst to a metallic monolith structure.