Zero-PGM TWC with High Redox Reversibility

Patent metadata

Field	Value
Publication number	US-2016361711-A1
Application number	US-201615182330-A
Country	US
Kind code	A1
Filing date	Jun 14, 2016
Priority date	Jun 15, 2015
Publication date	Dec 15, 2016
Grant date	—

Abstract

The present disclosure describes zero-platinum group metals (ZPGM) material compositions including binary Cu—Mn spinel oxide powders having stable reduction/oxidation (redox) reversibility useful for TWC and oxygen storage material applications. The behavior of Cu—Mn spinel oxide powder is analyzed under oxidation-reduction environments to determine redox reversibility, catalytic activity, and spinel structure stability. Characterization of spinel powder is performed employing X-ray diffraction analysis, hydrogen temperature-programmed reduction technique, transmission electron microscopy analysis, and X-ray photoelectron spectroscopy analysis. Test results confirm the phase and structural stability of the Cu—Mn spinel oxide during redox reaction, thereby indicating that the Cu—Mn spinel oxide can be employed in a plurality of TWC applications.

First claim

What is claimed is:

1 . A catalytic composition of a binary Cu—Mn spinel in which the catalytic composition comprises
a) a binary Cu—Mn spinel of the formula Cu X Mn 3−X O 4 , wherein X is a number from 0.01 to 2.99, and wherein the spinel comprises mixed phases of CuO, MnO and Cu X Mn 3−X O 4 ; b) a mixture of Cu and MnO; c) or a combination of a) and b).

2 . The catalytic composition of claim 1 , wherein the Cu—Mn spinel is CuMn 2 O 4 .

3 . The catalytic composition of claim 1 , wherein the composition is in the form of a powder.

4 . The catalytic composition according to claim 1 , wherein the Cu—Mn spinel is in a partially reduced state.

5 . The catalytic composition according to claim 1 , wherein the Cu—Mn spinel is in a fully reduced state.

6 . The catalytic composition according to claim 1 , wherein the composition comprises a CuO phase surrounded by a MnO phase.

7 . The catalytic composition of claim 6 , wherein the MnO phase is surrounded by Cu—Mn spinel particles.

8 . The catalytic composition of claim 1 , wherein the composition is free of platinum group metals.

9 . The catalytic composition of claim 1 , wherein a concentration of Cu 2+ is higher than a concentration of Cu 1+ in the catalytic composition.

10 . A catalytic converter comprising the composition of claim 1 .

11 . A method of removing one or more of nitrous oxide (NOx), carbon monoxide (CO) and hydrocarbons (HC) from an exhaust stream comprising the step of contacting the exhaust stream comprising one or more of NOx, CO, or HC with a catalytic composition, the catalytic composition comprising a) a binary Cu—Mn spinel of the formula Cu X Mn 3−X O 4 , wherein X is a number from 0.01 to 2.99, and wherein the spinel comprises mixed phases of CuO, MnO and Cu X Mn 3−X O 4 ; b) a mixture of Cu and MnO; c) or a combination of a) and b).

12 . The method of claim 11 , wherein the catalytic composition comprises said mixed phases of CuO, MnO and Cu X Mn 3−X O 4 .

13 . The method of claim 11 , wherein the catalytic composition comprises a mixture of Cu and MnO, and wherein the step of contacting the exhaust stream is carried out at a temperature of 400° C. to 600° C.

14 . The method of claim 11 , wherein the Cu—Mn spinel is CuMn 2 O 4 .

15 . The method of claim 11 , further comprising the step of oxidizing the catalyst composition to form a binary Cu—Mn spinel of the formula Cu X Mn 3−X O 4 , wherein X is a number from 0.01 to 2.99.

16 . A method of removing pollutants from a gas stream comprising:
a) contacting an exhaust stream comprising one or more of NOx, CO, or HC with a catalytic composition comprising a binary Cu—Mn spinel of the formula Cu X Mn 3−X O 4 , wherein X is a number from 0.01 to 2.99, and wherein the step of contacting results in a reduction of one or more of NOx, CO, or HC in the exhaust stream, and in the Cu—Mn spinel being reduced or partially reduced; b) contacting the exhaust stream with the reduced or partially reduced Cu—Mn spinel at a temperature that is between about 400° C. to about 600° C.; and c) oxidizing the catalytic composition following step b) to form a binary Cu—Mn spinel of the formula Cu X Mn 3−X O 4 .

17 . The method of claim 16 , wherein the partially reduced Cu—Mn spinel comprises mixed phases of CuO, MnO and Cu X Mn 3−X O 4 .

18 . The method of claim 16 , wherein the reduced Cu—Mn spinel comprises a mixture of Cu and MnO.

19 . The method of claim 16 , wherein the Cu—Mn spinel is in a partially reduced state, and wherein the composition comprises a CuO phase surrounded by a MnO phase on which Cu—Mn spinel particles are deposited.

20 . The method of claim 16 , wherein following step c), the concentration of Cu 2+ is higher than the concentration of Cu 1+ in the catalytic composition.

Assignees

• Clean Diesel Tech Inc

Inventors

• Nazarpoor Zahra
• Golden Stephen J

Classifications

• B01D2255/405

  Spinels · CPC title

• B01J23/005

  Spinels · CPC title

• B01J35/026

  Operations & Transport · mapped topic

• B01D53/945

  characterised by a specific catalyst · CPC title

• C01G45/1235

  of the type (Mn2O4)2-, e.g. Li2Mn2O4 or Li2(MxMn2-x)O4 · CPC title