Catalyst For Direct Nox Decomposition And A Method Of Forming And Using The Catalyst

Patent metadata

Field	Value
Publication number	US-2017246616-A1
Application number	US-201615055555-A
Country	US
Kind code	A1
Filing date	Feb 27, 2016
Priority date	Feb 27, 2016
Publication date	Aug 31, 2017
Grant date	—

Abstract

A process of forming a direct NOx catalyst includes the steps of providing a palladium salt, providing a silicon oxide support material, mixing the palladium salt and silicon oxide support material in an aqueous solution, evaporating the aqueous solution forming a solid, calcining the solid, and then exposing the calcined solid to a pretreatment gas at a specified temperature to form a desired direct NOx catalyst. When the process includes exposing the calcined solid to helium gas at a temperature of from 650 to 1000° C. the catalyst may include a mixture of palladium and palladium oxide having a particle size of from 5 to 150 nm where the palladium particles are discrete particles without sintering and the mixture may include 41% by weight palladium oxide and 51% by weight palladium metal.

First claim

What is claimed is:

1 . A process of forming a direct NOx catalyst comprising the steps of:
providing a palladium salt; providing a silicon oxide support material; mixing the palladium salt and silicon oxide support material in an aqueous solution; evaporating the aqueous solution forming a solid; calcining the solid; treating the calcined solid to helium gas at a temperature of from 650-1000° C. forming the direct NOx catalyst.

2 . The process of claim 1 wherein the palladium salt is selected from the group consisting of: nitrates, chlorides and acetates.

3 . The process of claim 1 wherein the step of calcining includes exposing the solid to a temperature of from 450° C. to 650° C. for a time period of from 3 to 10 hours.

4 . The process of claim 1 wherein the formed direct NOx catalyst includes a mixture of palladium and palladium oxide having a particle size of from 5-150 nm wherein the palladium particles are discrete particles without sintering.

5 . The process of claim 1 wherein the formed direct NOx catalyst includes 41% by weight palladium oxide and 51% by weight palladium metal.

6 . The process of claim 1 wherein the formed direct NOx catalyst has a NOx conversion of from 20 to 40% at a temperature of from 300 to 500° C.

7 . A process of forming a direct NOx catalyst comprising the steps of:
providing a palladium salt; providing a silicon oxide support material; mixing the palladium salt and silicon oxide support material in an aqueous solution; evaporating the aqueous solution forming a solid; calcining the solid; treating the calcined solid to hydrogen gas at a temperature of from 300-1000° C. forming the direct NOx catalyst.

8 . The process of claim 7 wherein the palladium salt is selected from the group consisting of: nitrates, chlorides and acetates.

9 . The process of claim 7 wherein the step of calcining includes exposing the solid to a temperature of from 450° C. to 650° C. for a time period of from 3 to 10 hours.

10 . The process of claim 7 wherein the formed direct NOx catalyst includes palladium particles having a particle size of from 50-2000 nm.

11 . The process of claim 7 wherein the formed direct NOx catalyst has a NOx conversion of from 10 to 50% at a temperature of from 300 to 800° C.

12 . A process of decomposing NOx comprising the steps of:
providing a catalyst including a mixture of palladium, palladium oxide and silicon oxide; contacting the catalyst with a gas at least including NOx directly decomposing the NOx to form nitrogen, nitrogen oxide or oxygen at a temperature of from 200 to 800° C.

13 . The process of claim 12 wherein the catalyst includes a mixture of palladium and palladium oxide having a particle size of from 5-150 nm wherein the palladium particles are discrete particles without sintering.

14 . The process of claim 12 wherein the catalyst includes 41% by weight palladium oxide and 51% by weight palladium metal.

15 . The process of claim 12 wherein the catalyst has a NOx conversion of from 20 to 40% at a temperature of from 300 to 500° C.

16 . A direct NOx catalyst consisting of:
a mixture of palladium, palladium oxide and silicon oxide, said mixture having a particle size of from 5-150 nm wherein the palladium particles are discrete particles without sintering.

17 . The direct NOx catalyst of claim 16 wherein the mixture includes 41% by weight palladium oxide and 51% by weight palladium metal.

18 . The direct NOx catalyst of claim 16 wherein the catalyst has a NOx conversion of from 20 to 40% at a temperature of from 300 to 500° C.

19 . A process of forming a direct NOx catalyst comprising the steps of:
providing a palladium salt; providing a silicon oxide support material; mixing the palladium salt and silicon oxide support material in an aqueous solution; evaporating the aqueous solution forming a solid; calcining the solid; treating the calcined solid to oxygen gas at a temperature of from 50-650° C. forming the direct NOx catalyst.

20 . The process of claim 19 wherein the palladium salt is selected from the group consisting of: nitrates, chlorides and acetates.

21 . The process of claim 19 wherein the step of calcining includes exposing the solid to a temperature of from 450° C. to 650° C. for a time period of from 3 to 10 hours.

22 . The process of claim 1 wherein the formed direct NOx catalyst has a NOx conversion of from 0 to 25% at a temperature of from 650 to 800° C.

Assignees

• Toyota Motor Eng & Mfg North America Inc

Inventors

• Gunugunuri Krishna Reddy
• Peck Torin C
• Ling Chen
• Jia Hongfei

Classifications

• B01J35/45

  Nanoparticles · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title

• B01J2235/15

  X-ray diffraction · CPC title

• B01J37/08

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