# US 2018/0021757 A1 · Rhodium-containing catalysts for automotive emissions treatment

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- Number: US 2018/0021757 A1
- Document ID: US20180021757A1
- Status: Published application
- Kind: A1
- Application number: 15/546,836
- Filed: 2016-01-29
- Published: 2018-01-25
- Earliest claimed: 2015-01-29
- Assignees: BASF SE; Georgia Tech Research Corporation
- Applicants: BASF Corporation; Georgia Tech Research Corporation
- Inventors: Andrey Karpov; David Preli; Knut Wassermann; Andreas Sundermann; Sang-IL Choi; Younan Xia
- Web page: https://patentgrep.com/patent/US20180021757A1

## CPC

- B01J 23/464: {Rhodium}
- B01D 53/945: {characterised by a specific catalyst}
- B01J 21/04: Alumina
- B01J 23/44: Palladium
- B01J 35/19: {Catalysts containing parts with different compositions}
- B01J 35/393: {Metal or metal oxide crystallite size}
- B01J 35/397: {Egg shell like}
- B01J 35/398: {Egg yolk like}
- B01J 35/45: Nanoparticles
- B01J 37/0072: {Preparation of particles, e.g. dispersion of droplets in an oil bath}
- B01J 37/009: {Preparation by separation, e.g. by filtration, decantation, screening}
- B01J 37/0211: {using a colloidal suspension}
- B01J 37/0213: {Preparation of the impregnating solution}
- B01J 37/0221: {of particles}
- B01J 37/0236: {Drying, e.g. preparing a suspension, adding a soluble salt and drying}
- B01J 37/024: {Multiple impregnation or coating}
- B01J 37/06: Washing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/16: Reducing
- B01D 2255/1023: Palladium
- B01D 2255/1025: Rhodium
- B01D 2255/204: Alkaline earth metals
- B01D 2255/2042: Barium
- B01D 2255/206: Rare earth metals
- B01D 2255/2061: Yttrium
- B01D 2255/2063: Lanthanum
- B01D 2255/2065: Cerium
- B01D 2255/2066: Praseodymium
- B01D 2255/2068: Neodymium
- B01D 2255/707: Additives or dopants
- B01D 2255/9202: Linear dimensions
- B01J 37/0018: {Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 2235/00: Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
- B01J 2235/30: Scanning electron microscopy; Transmission electron microscopy
- F01N 3/10: by thermal or catalytic conversion of noxious components of exhaust
- F01N 2570/10: Carbon or carbon oxides
- F01N 2570/12: Hydrocarbons
- F01N 2570/14: Nitrogen oxides
- Y02T 10/12: Improving ICE efficiencies
- 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)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Catalytic materials, and in particular, rhodium-containing catalytic materials for exhaust gas purifying catalyst composites are provided herein. Such materials comprise multimetallic Rh-containing nanoparticles, which are present primarily inside aggregated particles of a support (such as alumina). Such catalytic materials can exhibit excellent conversion of hydrocarbons and nitrogen oxides.

## Claims

### Claim 1

A catalytic material comprising:
a porous refractory metal oxide support in the form of aggregated particles; and
a plurality of rhodium-containing multimetallic nanoparticles, wherein at least about 50% by weight of the nanoparticles are located inside the aggregated particles of the support.

### Claim 2 (depends on 1)

The catalytic material of claim 1, wherein at least about 90% by weight of the nanoparticles are located inside the aggregated particles of the support.

### Claim 3 (depends on 1)

The catalytic material of claim 1, wherein the support comprises alumina.

### Claim 4 (depends on 1)

The catalytic material of claim 1, wherein the rhodium-containing multimetallic nanoparticles comprise palladium-rhodium bimetallic nanoparticles.

### Claim 5 (depends on 1)

The catalytic material of claim 1, wherein the average primary particle size of the rhodium-containing multimetallic nanoparticles is about 1 to about 20 nm as measured by Transmission Electron Microscopy (TEM).

### Claim 6 (depends on 1)

The catalytic material of claim 1, wherein the rhodium-containing multimetallic nanoparticles are colloidally delivered and thermally affixed to the support to form the catalytic material.

### Claim 7 (depends on 1)

The catalytic material of claim 1, wherein the average aggregated particle size of the support is about 1 micron or greater as measured by Scanning Electron Microscopy (SEM).

### Claim 8 (depends on 1)

The catalytic material of claim 1, wherein an average primary particle size of the support is about 1 to about 100 nm as measured by Transmission Electron Microscopy (TEM).

### Claim 9 (depends on 1)

The catalytic material of claim 1, wherein the support is colloidally delivered.

### Claim 10 (depends on 1)

The catalytic material of claim 1, wherein the support is pre-calcined.

### Claim 11 (depends on 1)

The catalytic material of claim 1, wherein the catalytic material is effective for conversion of one or more components of an exhaust stream of an internal combustion engine.

### Claim 12 (depends on 1)

The catalytic material of claim 1, further comprising one or both of a promoter and a stabilizer, in an amount of about 0.1 to about 30% by weight based on the weight of the catalytic material.

### Claim 13 (depends on 1)

The catalytic material of claim 1, wherein the material has a BJH desorption average pore radius of about 3 to about 30 nanometers as measured by nitrogen-pore size distribution (N2-PSD).

### Claim 14 (depends on 1)

The catalytic material of claim 1, wherein the material has a BET surface area greater than or equal to about 30 m2/g as measured by nitrogen adsorption isotherm.

### Claim 15 (depends on 5)

The catalytic material of claim 5, wherein after the catalytic material in fresh state is calcined at 550° C. for two hours in air, the rhodium-containing multimetallic nanoparticle average primary particle size remains about 1 to about 20 nm as measured by Transmission Electron Microscopy (TEM).

### Claim 16 (depends on 1)

The catalytic material of claim 1, wherein after the catalytic material in fresh state is calcined at 550° C. for two hours in air, the multimetallic nanoparticles remain in particle form and the metals do not segregate or dissolve into the aggregated particles of the support.

### Claim 17 (depends on 1)

The catalytic material of claim 1, wherein the rhodium-containing multimetallic nanoparticles further comprise a metal selected from the group consisting of palladium, platinum, ruthenium, osmium, iridium, copper, gold, silver, or a combination thereof.

### Claim 18 (depends on 1)

The catalytic material of claim 1, wherein the weight ratio of Pd:Rh is about 95:5 to about 5:95.

### Claim 19 (depends on 18)

The catalytic material of claim 18, wherein the weight ratio of Pd:Rh is about 1:1 to about 3:1.

### Claim 20 (depends on 19)

The catalytic material of claim 19, wherein the weight ratio of Pd:Rh is about 1.3:1 to about 2.7:1.

### Claim 21 (depends on 1)

The catalytic material of claim 1, wherein upon calcination in air at 550° C. for 2 hours, about 50% or more by weight of the rhodium has a binding energy of 307-309 eV as measured by X-ray photoelectron spectroscopy (XPS).

### Claim 22 (depends on 12)

The catalytic material of claim 12, wherein one or both of the promoter and the stabilizer is a rare earth oxide.

### Claim 23 (depends on 22)

The catalytic material of claim 22, wherein the rare earth oxide is selected from the group consisting of ceria, lanthana, neodymia, gadolinia, yttria, praseodymia, samaria, hafnia, and combinations thereof.

### Claim 24 (depends on 12)

The catalytic material of claim 12, wherein one or both of the promoter and the stabilizer is an alkaline earth oxide.

### Claim 25 (depends on 24)

The catalytic material of claim 24, wherein the alkaline earth oxide is selected from the group consisting of barium oxide, strontium oxide, or a combination thereof.

### Claim 26 (depends on 1)

The catalytic material of claim 1, wherein:
the refractory metal oxide support comprises alumina;
the catalytic material optionally comprises up to about 30% of a promoter, stabilizer, or both a promoter and a stabilizer;
the catalytic material BJH desorption average pore radius is about 3 to about 30 nanometers as measured by nitrogen-pore size distribution (N2-PSD); and
the rhodium-containing multimetallic nanoparticles are colloidally delivered and have an average primary particle size of about 1 to about 20 nanometers as measured by Transmission Electron Microscopy (TEM).

### Claim 27 (depends on 26)

The catalytic material of claim 26, wherein the catalytic material has a lower deactivation rate than a comparative catalytic material comprising individual rhodium and metal components as delivered by individual salts.

### Claim 28 (depends on 26)

The catalytic material of claim 26, wherein the catalytic material has higher NOx conversion activity than a comparative catalytic material comprising individual rhodium and metal components as delivered by individual salts.

### Claim 29 (depends on 1)

A catalyst composite for an exhaust stream of an internal combustion engine comprising: the catalytic material of claim 1 coated onto a carrier.

### Claim 30 (depends on 29)

The catalyst composite of claim 29, further comprising one or more additional components selected from platinum group metals, refractory metal oxide supports, promoters, and stabilizers, coated onto the carrier in the same layer as or a different layer than the catalytic material.

### Claim 31 (depends on 29)

A system for treatment of an internal combustion engine exhaust stream including hydrocarbons, carbon monoxide, nitrogen oxides, and other exhaust gas components, the emission treatment system comprising:
an exhaust conduit in fluid communication with the internal combustion engine via an exhaust manifold; and
the catalyst composite of claim 29.

### Claim 32 (depends on 29)

A method for treating exhaust gases comprising contacting a gaseous stream comprising hydrocarbons, carbon monoxide, and nitrogen oxides with the catalyst composite of claim 29.

### Claim 33

A method of making a catalytic material, the method comprising:
(a) obtaining rhodium-containing multimetallic nanoparticles;
(b) obtaining a refractory metal oxide support;
(c) preparing a solution of the nanoparticles of step (a) and the support of step (b) to form a catalytic material solution, wherein the support is in the form of aggregated particles;
(d) drying and calcining the catalytic material solution of step (c) to form the catalytic material, wherein at least about 50% by weight of the rhodium-containing multimetallic nanoparticles are located inside the aggregated particles of the support and are thermally affixed to the support.

### Claim 34 (depends on 33)

The method of claim 33, wherein the rhodium-containing multimetallic nanoparticles have an average primary particle size of about 10 to about 20 nm as measured by Transmission Electron Microscopy (TEM).

### Claim 35 (depends on 33)

The method of claim 33, wherein step (b) comprises obtaining nanoparticles of a refractory metal oxide support or a precursor of a refractory metal oxide support with an average primary particle size of about 1 to about 100 nm measured by Transmission Electron Microscopy (TEM) and step (c) comprises preparing an aqueous colloidal solution of the rhodium-containing nanoparticles of step (a) and the nanoparticles of step (b) to form the catalytic material solution.

### Claim 36 (depends on 33)

The method of claim 33, wherein step (b) comprises obtaining a pre-calcined refractory metal oxide support with an average aggregated particle size of about 1 micron or greater.

### Claim 37 (depends on 33)

The method of claim 33, wherein step (a) comprises:
forming an aqueous solution of a salt of rhodium and another metal, a reducing agent, and a surfactant; and
mixing and heating the aqueous solution, thereby reducing at least a portion of the metal to a zero valance form by action of the reducing agent in the presence of the surfactant and forming an aqueous solution of rhodium-containing multimetallic nanoparticles.

### Claim 38 (depends on 37)

The method of claim 37, wherein the reducing agent is selected from the group consisting of tetraethylene glycol, ascorbic acid (C6H8O6), oxalic acid (C2H2O4), formic acid (HCOOH), sodium borohydride (NaBH4), and mixtures thereof.

### Claim 39 (depends on 37)

The method of claim 37, wherein the surfactant is selected from the group consisting of poly(vinylalcohol), poly(vinylpyrrolidone), poly(ethyleneimine), poly(acrylic acid), carbohydrates, alkali metal citrates, and mixtures thereof.

### Claim 40 (depends on 33)

The method of claim 33, wherein, after calcination, the refractory metal oxide support comprises a high surface area gamma alumina having a surface area of at least about 60 square meters per gram (m2/g) and wherein the catalytic material optionally further comprises up to about 30% of a promoter, a stabilizer, or both a promoter and a stabilizer that comprises a rare earth oxide.