Catalyst for direct nox decomposition and a method of forming and using the catalyst

Patent metadata

Field	Value
Publication number	US-2018099264-A1
Application number	US-201715837355-A
Country	US
Kind code	A1
Filing date	Dec 11, 2017
Priority date	Feb 27, 2016
Publication date	Apr 12, 2018
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 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.

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

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

4 . A process of decomposing NOx comprising the steps of:
providing a catalyst according to claim 1 ; 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.

5 . The process of claim 4 wherein the catalyst includes 41% by weight palladium oxide and 51% by weight palladium metal.

6 . The process of claim 4 wherein the catalyst has a NOx conversion of from 20 to 40% at a temperature of from 300 to 500° C.

7 . A direct NOx catalyst consisting of:
silicon oxide and palladium particles having a size of from 50-2000 nm wherein the palladium particles are discrete particles without sintering.

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

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

10 . A process of decomposing NOx comprising the steps of:
providing a catalyst according to claim 7 ; 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 300 to 800° C.

Assignees

• Toyota Eng & Mfg North America

Inventors

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

Classifications

• B01J23/44 Primary

  Palladium · CPC title

• B01J35/023

  Operations & Transport · mapped topic

• B01J37/04

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

• B01J37/035

  Precipitation on carriers · CPC title

• B01J37/08

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