Mixed oxide and its use as NOx adsorber

Patent metadata

Field	Value
Publication number	US-11458450-B2
Application number	US-202117301151-A
Country	US
Kind code	B2
Filing date	Mar 26, 2021
Priority date	Mar 31, 2020
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

The present disclosure is directed to a mixed oxide composition comprising manganese, aluminum and/or magnesium, and a rare earth element; a method of making the mixed oxide composition; a NOx adsorber comprising the mixed oxide composition; an exhaust system for internal combustion engines comprising the NOx adsorber; and a method for reducing NOx in an exhaust gas that employs the NOx adsorber.

First claim

What is claimed:

1. A mixed oxide composition comprising:
(a) manganese;
(b) aluminum, magnesium, or a combination of aluminum and magnesium; and
(c) a rare earth element,
wherein the mixed oxide composition has a manganese to aluminum and magnesium atomic ratio of from about 100:20 to about 100:60 and a manganese to the rare earth element atomic ratio of from about 100:20 to about 100:60.

2. The mixed oxide composition of claim 1 , wherein the rare earth element is selected from the group consisting Ce, Y, La, and mixture thereof.

3. The mixed oxide composition of claim 1 , wherein the rare earth element is La.

4. The mixed oxide composition of claim 1 , wherein the manganese to aluminum and magnesium atomic ratio is from about 100:25 to about 100:55.

5. The mixed oxide composition of claim 1 having an aluminum to magnesium atomic ratio of from about 99:1 to about 1:99.

6. The mixed oxide composition of claim 1 having a manganese content of about 30 wt % to about 50 wt % relative to the mixed oxide composition.

7. The mixed oxide composition of claim 1 , further comprising an alkali metal selected from group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and mixture thereof.

8. The mixed oxide composition of claim 1 , further comprising an alkaline earth metal selected from group consisting of calcium (Ca), strontium (Sr), barium (Ba), and mixture thereof.

9. The mixed oxide composition of claim 1 , wherein the manganese, the aluminum and/or magnesium, and the rare earth element are substantially homogeneously distributed through the composition, as determined by energy-dispersive X-ray spectroscopy.

10. A method of making the mixed oxide composition of claim 1 , comprising:
a. mixing a manganese source, an aluminum source and/or a magnesium source, and a rare earth element source to form an aqueous solution having a manganese to aluminum and magnesium atomic ratio of from about 100:20 to about 100:60 and a manganese to the rare earth element atomic ratio of from about 100:20 to about 100:60;
b. mixing the aqueous solution with an alkali solution to form a slurry comprising a solid;
c. and isolating the solid.

11. The method of claim 10 , whereas the slurry has a pH of from about 9 to about 12.

12. The method of claim 10 , whereas the slurry has a pH of from about 9.5 to about 11.5.

13. The method of claim 10 , whereas the slurry has a pH of from about 10 to about 11.

14. The method of claim 10 , further comprising washing the solid.

15. The method of claim 14 , further comprising drying the solid.

16. A NOx adsorber comprising the mixed oxide composition of claim 1 .

17. An exhaust system for internal combustion engines comprising the NOx adsorber of claim 16 and a catalyst component selected from the group consisting a selective catalytic reduction (SCR) catalyst, a particulate filter, a SCR filter, a three-way catalyst, an oxidation catalyst, a second NOx adsorber catalyst, and combinations thereof.

18. A method for treating exhaust gas from an internal combustion engine, comprising adsorbing NOx by the NOx adsorber of claim 16 at temperatures at or below a low temperature, thermally desorbing NOx from the NOx adsorber at a temperature above the low temperature, and catalytically removing the desorbed NOx on a catalyst component downstream of the NOx adsorber.

Assignees

• Johnson Matthey Plc

Inventors

• Duran-Martin Desiree
• Villoria Jose

Classifications

• B01J20/3085

  Chemical treatments not covered by groups B01J20/3007 - B01J20/3078 · CPC title

• C01P2002/52

  containing elements as dopants · CPC title

• C01G45/12

  Complex oxides containing manganese and at least one other metal element · CPC title

• B01J20/3071

  Washing or leaching · CPC title

• F01N3/2066

  Selective catalytic reduction [SCR] · CPC title