# US 2014/0193745 A1 · Substrate surface structured with thermally stable metal alloy nanoparticles, a method for preparing the same and uses thereof, in particular as a catalyst

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- Number: US 2014/0193745 A1
- Document ID: US20140193745A1
- Status: Published application
- Kind: A1
- Application number: 14/235,442
- Filed: 2012-07-27
- Published: 2014-07-10
- Earliest claimed: 2011-07-27
- Assignees: Max-Planck-Gesellschaft zur Foerderung der Wissenschaften e.V.
- Inventors: Joachim P. Spatz; Sebastian Lechner
- Web page: https://patentgrep.com/patent/US20140193745A1

## CPC

- B01D 53/94: by catalytic processes
- B01J 23/38: of noble metals
- B01J 23/464: {Rhodium}
- B01J 23/52: Gold
- B01J 23/89: combined with noble metals
- B01J 23/892: {Nickel and noble metals}
- B01J 35/45: Nanoparticles
- 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 37/0219: {the coating containing organic compounds}
- B01J 37/082: {Decomposition and pyrolysis}
- B01J 37/18: with gases containing free hydrogen
- B01J 37/349: {making use of flames, plasmas or lasers}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- C03C 17/10: by deposition from the liquid phase
- H01M 4/8657: {layered}
- H01M 4/8803: {Supports for the deposition of the catalytic active composition (H01M4/90 takes precedence)}
- H01M 4/8842: {Coating using a catalyst salt precursor in solution followed by evaporation and reduction of the precursor}
- H01M 4/8882: {Heat treatment, e.g. drying, baking}
- H01M 4/9041: {Metals or alloys (H01M4/92 takes precedence)}
- H01M 4/921: {Alloys or mixtures with metallic elements}
- H01M 8/0662: Treatment of gaseous reactants or gaseous residues, e.g. cleaning
- H01M 8/0668: Removal of carbon monoxide or carbon dioxide
- B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)}
- B01D 2255/1021: Platinum
- B01D 2255/1025: Rhodium
- B01D 2255/106: Gold
- B01D 2255/20753: Nickel
- B01J 21/08: Silica
- B01J 35/58: Fabrics or filaments
- B01J 35/643: {less than 2 nm}
- C03C 2218/32: After-treatment
- Y02E 60/50: Fuel cells
- 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)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The invention relates to a method for preparing a substrate surface structured with thermally stable metal alloy nanoparticles, which method comprises—providing a micellar solution of amphiphilic molecules such as organic diblock or multiblock copolymers in a suitable solvent; —loading the micelles of said micellar solution with metal ions of a first metal salt; —loading the micelles of said micellar solution with metal ions of at least one second metal salt; —depositing the metal ion-loaded micellar solution onto a substrate surface to form a (polymer) film comprising an ordered array of (polymer) domains; co-reducing the metal ions contained in the deposited domains of the (polymer) film by means of a plasma treatment to form an ordered array of nanoparticles consisting of an alloy of the metals used for loading the micelles on the substrate surface. The invention also provides a nanostructured substrate surface obtainable by said method as well as the use of said nanostructured substrate surface as a catalyst.

## Claims

### Claim 1

A method for preparing a substrate surface structured with thermally stable metal alloy nanoparticles comprising
providing a micellar solution of amphiphilic molecules in a suitable solvent;
loading the micelles of said micellar solution with metal ions of a first metal salt;
loading the micelles of said micellar solution with metal ions of at least one second metal salt;
depositing the metal ion-loaded micellar solution onto a substrate surface to form a film comprising an ordered array of domains;
co-reducing the metal ions contained in the deposited domains of the film by use of a plasma treatment to form an ordered array of nanoparticles comprising an alloy of the metals used for loading the micelles on the substrate surface.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the amphiphilic molecules are selected from the group consisting of compounds of the general formula R—X, with X being a polar or charged functional group, and R being a straight or branched carbon chain with 5 or more C atoms, bifunctional compounds having the general formula Y—R—X, with X and Y, which are different, being a polar or charged functional group, and R being straight branched carbon chain with 5 or more C atoms, dendrimers, organic diblock or multiblock copolymers, thiolated oligonucleotides and polyethylene glycols.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the amphiphilic molecules are organic diblock or multiblock copolymers and the method comprises
providing a micellar solution of an organic diblock or multiblock copolymer in a suitable solvent;
loading the micelles of said micellar solution with metal ions of a first metal salt;
loading the micelles of said micellar solution with metal ions of at least one second metal salt;
depositing the metal ion-loaded micellar solution onto a substrate surface to form a polymer film comprising an ordered array of polymer domains;
co-reducing the metal ions contained in the deposited domains of the polymer film by use of a plasma treatment to form an ordered array of nanoparticles comprising an alloy of the metals used for loading the micelles on the substrate surface.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the first metal is a noble metal, and the at least one second metal is selected from the group consisting of noble metals and transition metals.

### Claim 5 (depends on 1)

The method according to claim 1, wherein a molar ratio of the first metal to the at least one second metal is in a range from 9:1 to 1:9.

### Claim 6 (depends on 3)

The method according to claim 3, wherein the diblock or multiblock copolymer is selected from the group consisting of polystyrene-b-polyethylenoxide, polystyrene-b-poly(2-vinylpyridine), polystyrene-b-poly(4-vinyl-pyridine) and mixtures thereof.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the plasma treatment is effected for a time period of at least 60 minutes.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the co-reduction of the metal ions is effected by use of a gas plasma comprising hydrogen.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the gas plasma is selected from the group consisting of pure hydrogen and a mixture of hydrogen and inert gas.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the nanoparticles are thermally stable up to a temperature at least 450° C.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the substrate surface is selected from the group consisting of Si, Si coated with a native oxide layer, SiO2, glass, TiO2, ZnO, alumina, silica/alumina, carbon and carbon-based materials.

### Claim 12 (depends on 1)

A substrate surface comprising an array of thermally stable metal alloy nanoparticles obtainable with the method according to claim 1.

### Claim 13 (depends on 12)

The substrate surface according to claim 12, wherein the metal alloy is an alloy of Au and Pt, an alloy of Rh and Pt, or an alloy of Ni and Pt.

### Claim 14 (depends on 12)

The substrate surface according to claim 12, which is a bead or particle having a diameter in a micrometer range, a mesoporous material comprising particles or aggregates of particles, or a fibrous material.

### Claim 15 (depends on 14)

The substrate surface according to claim 14, wherein the mesoporous material comprises silica, alumina or silica/alumina.

### Claim 16 (depends on 12)

A method for catalyzing a reaction, said method comprising contacting reactants with the substrate surface according to claim 12.

### Claim 17 (depends on 16)

The method according to claim 16, wherein the substrate surface is a catalyst for treating/decontaminating car exhaust emissions or a catalyst for fuel cells.

### Claim 18

A method for nanostructuring a substrate surface which is a bead or particle having a diameter in a micrometer range, a mesoporous material comprising particles or aggregates of particles, or a fibrous material, comprising
a) providing a micellar solution of amphiphilic molecules in a suitable solvent and loading the micelles of said micellar solution with metal ions of at least one metal salt;
b) contacting the metal ion-loaded micellar solution with said beads, particles, mesoporous material or fibrous material by pressing said metal ion-loaded micellar solution through a layer of the beads, particles, mesoporous material or fibrous material which is provided on a porous support without adhering to said support and subsequently drying the beads, particles, mesoporous material or fibrous material, whereby a film comprising an ordered array of domains is formed on the surface of the beads, particles, mesoporous material or fibrous material; and
c) reducing the metal ions contained in the deposited domains of the film to form an ordered array of nanoparticles on the bead, microparticle, mesoporous material or fibrous material substrate surface.

### Claim 19 (depends on 18)

The method according to claim 18, wherein in step a) the micelles are loaded with a salt of a first metal and a salt of at least one second metal different from the first metal and step c) comprises a co-reduction of the different metal ions to form alloy nanoparticles.

### Claim 20 (depends on 19)

The method according to claim 19, wherein in said alloy nanoparticles the first metal is a noble metal, and at least one second metal is selected from the group consisting of Pt, Pd, Rh, and transition metals.

### Claim 21 (depends on 20)

The method according to claim 20, wherein the alloy nanoparticles are Au/Pt nanoparticles, Rh/Pt nanoparticles or Ni/Pt nanoparticles.