Solution-based approach to make porous coatings for sinter-resistant catalysts

Patent metadata

Field	Value
Publication number	US-10376872-B2
Application number	US-201715399179-A
Country	US
Kind code	B2
Filing date	Jan 5, 2017
Priority date	Jan 5, 2017
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

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.

First claim

What is claimed is:

1. A method of preparing a sinter-resistant catalyst system, the method comprising:
disposing a support having a surface comprising a catalyst particle in a reducing atmosphere to promote conversion of the catalyst particle to a metallic state; contacting the support having the surface comprising the catalyst particle with a solution comprising a metal salt and having an acidic pH, wherein the metal salt comprises 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;
precipitating the metal salt onto the surface of the support; and
calcining the metal salt to selectively generate a porous coating of metal oxide on the surface of the support distributed around the catalyst particle, so that at least a portion of the catalyst particle is exposed and available for reaction.

2. The method according to claim 1 , wherein the solution comprising the metal salt is aqueous and the pH is less than or equal to about 6.

3. The method according to claim 1 , wherein the catalyst particle comprises a metal selected from the group consisting of: platinum (Pt), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), gold (Au), iron (Fe), nickel (Ni), manganese (Mn), and combinations thereof.

4. The method according to claim 1 , wherein the support comprises a metal oxide selected from the group consisting of: cerium oxide (CeO 2 ), aluminum oxide (Al 2 O 3 ), zirconium oxide (ZrO 2 ), titanium dioxide (TiO 2 ), silicon dioxide (SiO 2 ), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K 2 O), sodium oxide (Na 2 O), calcium oxide (CaO), lanthanum oxide (La 2 O 3 ), and combinations thereof.

5. The method according to claim 1 , wherein the metal salt is selected from the group consisting of: aluminum chloride (AlCl 3 ), aluminum nitrate (Al(NO 3 ) 3 ), aluminum hydroxide (Al(OH) 3 ), aluminum sulfate (Al 2 (SO 4 ) 3 ), aluminum chlorate (Al(ClO 3 ) 3 ), aluminum phosphate (AlPO 4 ), aluminum metaphosphate (Al(PO 3 ) 3 ), and combinations thereof.

6. The method according to claim 1 , wherein prior to the contacting, the method further comprises washing the surface of the support comprising the catalyst particle with an acidic solution.

7. The method of claim 1 , wherein the disposing the support comprising the catalyst particle in the reducing atmosphere further comprises:
disposing the support comprising the catalyst particle in a furnace;
purging the furnace with a gas mixture comprising an inert gas and hydrogen (H 2 ) at less than or equal to about 3% by volume for greater than or equal to about 30 minutes;
heating the support comprising the catalyst particle in the furnace having a temperature of greater than or equal to about 200° C. to less than or equal to about 500° C.;
maintaining the support comprising the catalyst particle at the temperature for greater than or equal to about 30 minutes; and
cooling the support comprising the catalyst particle to ambient conditions.

8. The method according to claim 7 , wherein heating the support comprising a catalyst particle occurs at a rate of less than or equal to about 20° C. per minute.

9. The method according to claim 7 , wherein the purging comprises purging the furnace with the gas mixture having a flow rate of greater than or equal to about 1 standard cubic feet per hour (SCFH).

10. The method according to claim 1 , wherein the contacting of the support having the surface comprising the catalyst particle with the solution includes submerging the surface in the solution, wherein the method further comprises applying ultrasound to the solution to facilitate the precipitating or the method further comprises applying mixing the solution with a planetary centrifugal mixer to facilitate the precipitating.

11. The method according to claim 1 , wherein the precipitating the metal salt onto the surface of the support comprises drying the solution comprising the metal salt to facilitate the precipitation.

12. The method according to claim 11 , wherein the drying occurs at a temperature of greater than or equal to about 50° C. and at a pressure of less than or equal to about 1 Torr for a time of greater than or equal to about 4 hours.

13. The method according to claim 1 , wherein the calcining the metal salt to selectively generate a porous coating of metal oxide on the support comprises heating the metal salt and the catalyst particle disposed on the support at greater than or equal to about 400° C. to less than or equal to about 600° C. for greater than or equal to about 2 hours.

14. A method of preparing a sinter-resistant catalyst system, the method comprising:
disposing a plurality of support particles each comprising a surface bearing at least one catalyst particle in a reducing atmosphere to promote conversion of the catalyst particle to a metallic state; contacting the plurality of support particles each comprising the surface bearing at least one catalyst particle with a liquid comprising a metal salt and having a pH of less than or equal to about 6, wherein the metal salt comprises 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;
precipitating the metal salt onto the surface bearing the at least one catalyst particle; and
calcining the metal salt to selectively generate a porous coating of metal oxide on the surface bearing the at least one catalyst particle, wherein the porous coating is distributed around the at least one catalyst particle on the surface, so that at least a portion of the catalyst particle is exposed and available for reaction.

15. The method of claim 14 , wherein the disposing the support comprising the catalyst particle in the reducing atmosphere further comprises:
disposing the plurality of support particles comprising the at least one catalyst particle in a furnace;
purging the furnace with a gas mixture comprising an inert gas and hydrogen (H 2 ) at less than or equal to about 3% by volume for greater than or equal to about 30 minutes;
heating the plurality of support particles comprising the at least one catalyst particle in the furnace having a temperature of greater than or equal to about 200° C. to less than or equal to about 500° C.;
maintaining the support comprising the catalyst particle at the temperature for greater than or equal to about 30 minutes; and
cooling the plurality of support particles comprising the at least one catalyst particle to ambient conditions.

16. A method of preparing a sinter-resistant catalyst system, the method comprising:
disposing a support having a surface comprising a catalyst particle in a reducing atmosphere to promote conversion of the catalyst particle to a metallic state; contacting the support having the surface comprising the catalyst particle with a solution comprising a metal salt and having an acidic pH, wherein the metal salt comprises 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 and the catalyst particle comprises a metal selected from the group consisting of: platinum (Pt), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), gold (Au), iron (Fe), nickel (Ni), and c

Assignees

• Gm Global Tech Operations Llc

Inventors

• Xiao Xingcheng
• Qi Gongshin
• Day Ryan J
• Yang Ming

Classifications

• B01J23/42

  Platinum · CPC title

• B01J37/035 Primary

  Precipitation on carriers · CPC title

• B01J23/44 Primary

  Palladium · CPC title

• B01J37/08

  Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• B01J37/343

  of ultrasonic wave energy · CPC title