# US 9,517,449 B2 · Optimization of washcoat adhesion of zero-PGM catalyst on metallic substrates

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- Number: US 9,517,449 B2
- Document ID: US9517449B2
- Status: Granted
- Kind: B2
- Application number: 13/927,850
- Filed: 2013-06-26
- Published: 2015-01-01
- Granted: 2016-12-13
- Earliest claimed: 2013-06-26
- Assignees: Clean Diesel Technologies, Inc.
- Applicants: Clean Diesel Technologies, Inc.
- Inventors: Zahra Nazarpoor; Sen Kitazumi; Johnny T. Ngo
- Web page: https://patentgrep.com/patent/US9517449B2

## CPC

- B01J 23/72: Copper
- B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)}
- B01J 23/83: with rare earths or actinides
- B01J 35/40: characterised by dimensions, e.g. grain size (in a colloidal state B01J35/23; crystallite size B01J35/77)
- B01J 37/0225: {of metal substrates}
- B01D 2255/206: Rare earth metals
- B01D 2255/207: Transition metals
- B01D 2255/65: Catalysts not containing noble metals
- B01D 2255/908: O2-storage component incorporated in the catalyst
- B01J 35/394: {Metal dispersion value, e.g. percentage or fraction}
- B01J 37/0036: {Grinding}
- B01J 37/03: Precipitation; Co-precipitation
- B01J 2235/15: X-ray diffraction
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

Solutions to the problem of washcoat and/or overcoat adhesion loss of ZPGM catalyst on metallic substrates are disclosed. Present disclosure provides a novel process for improving WCA to metallic substrates of ZPGM catalyst systems. Reduction of WCA loss and improved catalyst activity may be enabled by the selection of processing parameters determined from variations of pH and addition of binder to overcoat slurry, and particle size of washcoat. Processing parameters may be applied to a plurality of metallic substrates of different geometries and cell densities.

## Claims

### Claim 1

A method for manufacturing a catalyst system, the method comprising:
providing at least one substrate;
depositing a washcoat onto the substrate; adjusting a pH of at least one chemical slurry suitable for deposition on the substrate and comprising at least one ZPGM catalyst, wherein the chemical slurry comprises alumina or doped alumina, or a mixture thereof, an oxygen storage material, copper oxide, and cerium oxide; and
depositing the at least one chemical slurry overlying the washcoat, wherein the average particle size of the at least one chemical slurry is about 7 μm, and the pH is about 6.8 and wherein loading of the copper oxide is from 10 g/L to 15 g/L and the loading of the cerium oxide is from 12 g/L to 18 g/L.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the substrate comprises about 300 to about 400 cells per square inch.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the substrate is metallic.

### Claim 4

A method for manufacturing a catalyst system, the method comprising:
providing at least one substrate;
depositing a washcoat on the substrate:
adjusting a pH of at least one chemical slurry suitable for deposition on the substrate and comprising at least one ZPGM catalyst, wherein the at least one chemical slurry comprises alumina as a binder; and
depositing the at least one chemical slurry on the substrate, wherein the pH of the at least one chemical slurry is about 6.8 and wherein the average particle size of the at least one chemical slurry is about 7 μm and wherein loading of a copper oxide is from 10 g/L to 15 g/L and the loading of a cerium oxide is from 12 g/L to 18 g/L.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the oxygen storage material including at least one selected from the group consisting of Ce, Zr, Nd, and Pr.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the at least one ZPGM catalyst is prepared by at least one method selected from the group consisting of co-milling and co-precipitation.

### Claim 7 (depends on 1)

The method according to claim 1, wherein loss of deposited chemical slurry is less than about 3%.

### Claim 8 (depends on 4)

The method according to claim 4, wherein the catalyst system obtains a T50 of hydrocarbons less than 320° C. in a light-off test under lean condition and wherein the light-off test uses toluene as feed hydrocarbon.

### Claim 9 (depends on 2)

The method according to claim 2, wherein the substrate comprises about 400 cells per square inch.