SOLUTION-BASED APPROACH TO MAKE POROUS COATINGS FOR SINTER-RESISTANT CATALYSTS

• US 20190314804A1
• Filed: 06/27/2019
• Published: 10/17/2019
• Est. Priority Date: 01/05/2017
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: XIAO, Xingcheng, QI, Gongshin, DAY, Ryan J., YANG, Ming
• Granted Patent: US 11,951,465 B2
• Time in Patent Office: Days
• CPC Class Codes: B01J 23/42 Platinum
• CPC Class Codes: B01J 23/44 Palladium
• CPC Class Codes: B01J 35/23 in a colloidal state
• CPC Class Codes: B01J 35/398 Egg yolk like
• CPC Class Codes: B01J 35/45 Nanoparticles
• CPC Class Codes: B01J 37/035 Precipitation on carriers
• CPC Class Codes: B01J 37/08 Heat treatment B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 37/18 with gases containing free hydrogen

Abstract

Catalyst systems that are resistant to high-temperature sintering and methods for preparing such catalyst systems that are resistant to sintering at high temperatures are provided. Methods of forming such catalyst systems include contacting a support having a surface including a catalyst particle with a solution comprising a metal salt and having an acidic pH. The metal salt is precipitated onto the surface of the support. Next, the metal salt is calcined to selectively generate a porous coating of metal oxide on the surface of the support distributed around the catalyst particle.

Claims

1. A catalyst system comprising:

a platinum group metal catalyst bound to a metal oxide support; and

a crystalline coating of metal oxide nanoparticles selectively disposed on the metal oxide support, wherein the crystalline coating has a porosity of greater than about 20% to less than about 70% and covers greater than or equal to about 1.5% to less than or equal to about 80% of an exposed surface area of the metal oxide support.

2. The catalyst system according to claim 1, wherein the platinum group metal catalyst comprises a metal selected from the group consisting of:

platinum (Pt), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), gold (Au), and combinations thereof.

3. The catalyst system according to claim 1, wherein the metal oxide nanoparticles comprise an element selected from the group consisting of:

aluminum (Al), cerium (Ce), zirconium (Zr), titanium (Ti), silicon (Si), magnesium (Mg), zinc (Zn), sodium (Na), potassium (K), barium (Ba), calcium (Ca), and combinations thereof.

4. The catalyst system according to claim 1, wherein the metal oxide nanoparticles comprise a metal oxide selected from the group consisting of:

aluminum oxide (Al₂O₃), cerium oxide (CeO₂), zirconium oxide (ZrO₂), titanium dioxide (TiO₂), silicon dioxide (SiO₂), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K₂O), sodium oxide (Na₂O), calcium oxide (CaO), and combinations thereof.

5. The catalyst system according to claim 1, wherein the metal oxide support comprises a metal oxide selected from the group consisting of:

cerium oxide (CeO₂), aluminum oxide (Al₂O₃), zirconium oxide (ZrO₂), titanium dioxide (TiO₂), silicon dioxide (SiO₂), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K₂O), sodium oxide (Na₂O), calcium oxide (CaO), lanthanum oxide (La₂O₃), and combinations thereof; and

the metal oxide nanoparticles comprise aluminum oxide (Al₂O₃).

6. The catalyst system according to claim 1, wherein the metal oxide support comprises aluminum oxide (Al₂O₃) and the metal oxide nanoparticles comprise aluminum oxide (Al₂O₃).

7. The catalyst system according to claim 1, wherein a loading density of the platinum group metal catalyst on the metal oxide support is greater than or equal to about 0.25% (w/w) to less than or equal to about 20% (w/w).

8. The catalyst system according to claim 1, wherein the metal oxide support is a monolith structure or a particle.

9. The catalyst system according to claim 1, wherein the metal oxide nanoparticles have an average diameter of greater than or equal to about 0.5 nm to less than or equal to about 50 nm and the crystalline coating comprises pores having an average diameter of greater than or equal to about 0.5 nm to less than or equal to about 30 nm.

10. A catalyst system comprising:

a platinum group metal catalyst selected from the group consisting of;

palladium, platinum, and combinations thereof bound to a metal oxide support; and

a crystalline coating of metal oxide nanoparticles selectively disposed on the metal oxide support distributed around the platinum group metal catalyst, wherein the crystalline coating has a porosity of greater than about 20% to less than about 70% and covers greater than or equal to about 1.5% to less than or equal to about 80% of an exposed surface area of the metal oxide support.

11. The catalyst system according to claim 10, wherein the metal oxide nanoparticles comprise a metal oxide selected from the group consisting of:

aluminum oxide (Al₂O₃), cerium oxide (CeO₂), zirconium oxide (ZrO₂), titanium dioxide (TiO₂), silicon dioxide (SiO₂), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K₂O), sodium oxide (Na₂O), calcium oxide (CaO), and combinations thereof.

12. The catalyst system according to claim 10, wherein the metal oxide support comprises a metal oxide selected from the group consisting of:

cerium oxide (CeO₂), aluminum oxide (Al₂O₃), zirconium oxide (ZrO₂), titanium dioxide (TiO₂), silicon dioxide (SiO₂), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K₂O), sodium oxide (Na₂O), calcium oxide (CaO), lanthanum oxide (La₂O₃), and combinations thereof; and

the metal oxide nanoparticles comprise aluminum oxide (Al₂O₃).

13. The catalyst system according to claim 10, wherein the metal oxide support comprises aluminum oxide (Al₂O₃) and the metal oxide nanoparticles comprise aluminum oxide (Al₂O₃).

14. The catalyst system according to claim 10, wherein a loading density of the platinum group metal catalyst on the metal oxide support is greater than or equal to about 0.25% (w/w) to less than or equal to about 20% (w/w).

15. The catalyst system according to claim 10, wherein the metal oxide support is a monolith structure or a particle.

16. The catalyst system according to claim 10, wherein the metal oxide nanoparticles have an average diameter of greater than or equal to about 0.5 nm to less than or equal to about 50 nm and the crystalline coating comprises pores having an average diameter of greater than or equal to about 0.5 nm to less than or equal to about 30 nm.

17. A catalyst system comprising:

a platinum group metal catalyst selected from the group consisting of;

palladium, platinum, and combinations thereof bound to a metal oxide support; and

a crystalline coating of metal oxide nanoparticles that comprise aluminum oxide (Al₂O₃) selectively disposed on the metal oxide support comprising aluminum oxide (Al₂O₃), wherein the metal oxide nanoparticles have an average maximum diameter of greater than or equal to about 0.5 nm to less than or equal to about 50 nm and the crystalline coating has a porosity of greater than about 20% to less than about 70% and covers greater than or equal to about 1.5% to less than or equal to about 80% of an exposed surface area of the metal oxide support.

18. The catalyst system according to claim 17, wherein a loading density of the platinum group metal catalyst on the metal oxide support is greater than or equal to about 0.25% (w/w) to less than or equal to about 20% (w/w).

19. The catalyst system according to claim 17, wherein the metal oxide support is a monolith structure or a particle.