# US 11,110,433 B2 · Metal-doped tin oxide for electrocatalysis applications

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- Number: US 11,110,433 B2
- Document ID: US11110433B2
- Status: Granted
- Kind: B2
- Application number: 16/084,263
- Filed: 2017-03-17
- Published: 2019-02-28
- Granted: 2021-09-07
- Earliest claimed: 2016-03-18
- Assignees: BASF SE
- Applicants: BASF SE
- Inventors: Xu Yuan Peng; Rosalba Adriana Ricon-Ovalles; Shyam Sundar Venkataraman; Domnik Bayer; Andreas Haas
- Web page: https://patentgrep.com/patent/US11110433B2

## CPC

- B01J 23/14: of germanium, tin or lead
- B01J 23/18: Arsenic, antimony or bismuth
- B01J 35/33: Electric or magnetic properties
- B01J 35/613: {10-100 m2/g}
- B01J 35/615: {100-500 m2/g}
- B01J 37/031: {Precipitation}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- C25B 1/04: by electrolysis of water
- C25B 9/19: with diaphragms
- C25B 9/73: of the filter-press type
- C25B 11/093: at least one noble metal or noble metal oxide and at least one non-noble metal oxide
- H01M 4/8803: {Supports for the deposition of the catalytic active composition (H01M4/90 takes precedence)}
- H01M 4/9075: {Catalytic material supported on carriers, e.g. powder carriers (H01M4/8807, H01M4/881, H01M4/8814, H01M4/925 take precedence)}
- H01M 4/9083: {on carbon or graphite}
- H01M 4/925: {supported on carriers, e.g. powder carriers}
- H01M 8/1018: Polymeric electrolyte materials
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- Y02E 60/36: Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
- Y02E 60/50: Fuel cells
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- 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 present invention relates to a metal-doped tin oxide which has a BET surface area of at least 30 m 2/g, and comprises at least one metal dopant which is Sb, Nb, Ta, Bi, W, or In, or any mixture thereof, wherein the metal dopant is present in an amount of from 2.5 at % to 25 at %, based on the total amount of tin and metal dopant atoms, and is in a mixed valence state containing atoms of oxidation state OS1 and atoms of oxidation state OS2, wherein the oxidation state OS1 is >0 and the oxidation state OS2 is >OS1 and the atomic ratio of the atoms of OS2 to the atoms of OS1 is from 1.5 to 12.0.

## Claims

### Claim 1

A metal-doped tin oxide which
has a BET surface area of at least 30 m2/g, and
comprises a dopant which is Sb,
wherein the metal dopant
is present in an amount of from 2.5 at % to 25 at %, based on the total amount of tin and metal dopant atoms, and
is in a mixed valence state containing Sb3+ atoms and Sb5+ atoms, wherein the atomic ratio of Sb5+ to Sb3+, measured by X-ray photoelectron spectroscopy, is from 5.0 to 9.0.

### Claim 2 (depends on 1)

The metal-doped tin oxide according to claim 1, wherein the amount of the metal dopant is from 2.5 at % to 10.0 at %.

### Claim 3 (depends on 1)

The metal-doped tin oxide according to claim 1, wherein the BET surface area of the metal-doped tin oxide is from 30 m2/g to 150 m2/g and/or the electrical conductivity of the metal doped tin oxide is at least 0.02 S/cm.

### Claim 4 (depends on 1)

The metal-doped tin oxide according to claim 1, wherein the amount of the metal dopant is from 5.0 at % to 7.5 at %.

### Claim 5 (depends on 1)

The metal-doped tin oxide according to claim 1, wherein the BET surface area of the metal-doped tin oxide is from 35 m2/g to 110 m2/g; and/or the electrical conductivity of the metal doped tin oxide is at least 0.03 S/cm.

### Claim 6 (depends on 1)

The metal-doped tin oxide according to claim 1, wherein the atomic ratio of the Sb5+ atoms to the Sb3+ atoms is from 5.0 to 8.0.

### Claim 7 (depends on 1)

A process for preparing the metal-doped tin oxide according to claim 1, comprising
preparing a metal-doped precursor solid by a wet chemical synthesis from a reaction mixture comprising a tin-containing molecular precursor compound and a metal-dopant-containing molecular precursor compound,
subjecting the metal-doped precursor solid to a thermal treatment.

### Claim 8 (depends on 7)

The process according to claim 7, wherein the wet chemical synthesis is a sol-gel process, a chemical precipitation process, a hydrothermal synthesis process, a spray drying process, or any combination thereof.

### Claim 9 (depends on 7)

The process according to claim 7, wherein the tin-containing molecular precursor compound and the metal-dopant-containing molecular precursor compound are mixed at acidic pH, and the pH is subsequently raised by adding a base until the metal-doped precursor solid precipitates; and/or wherein the wet chemical synthesis is carried out in an alcoholic solvent.

### Claim 10 (depends on 7)

The process according to claim 7, wherein the tin-containing molecular precursor compound is a tin salt such as a tin halide or a tin nitrate, or a tin alkoxide, or a mixture thereof; and/or the metal-dopant-containing molecular precursor compound is a metal halide, a metal carboxylate or a metal alkoxide or any mixture thereof.

### Claim 11 (depends on 7)

The process according to claim 7, wherein the wet chemical synthesis is carried out in the presence of a solid additive having a BET surface area of at least 40 m2/g.

### Claim 12 (depends on 11)

The process according to claim 11, wherein the solid additive is carbon black or activated carbon, which has a BET surface area of at least 200 m2/g.

### Claim 13 (depends on 7)

The process according to claim 7, wherein the thermal treatment includes heating to a temperature of from 400 to 800° C.

### Claim 14 (depends on 11)

The process according to claim 11, wherein the solid additive is carbon black or activated carbon, which has a BET surface area of at least 500 m2/g.

### Claim 15 (depends on 1)

A composite material, comprising the metal-doped tin oxide according to claim 1, and an electrocatalyst which is supported on the metal-doped tin oxide.

### Claim 16 (depends on 15)

An electrochemical device, comprising the composite material according to claim 15.

### Claim 17 (depends on 16)

The electrochemical device according to claim 16, wherein the electrochemical device is a polymer electrolyte membrane PEM water electrolyzer or a PEM fuel cell.

### Claim 18 (depends on 1)

A catalyst support in an electrochemical device, comprising the metal-doped tin oxide according claim 1, wherein the electrochemical device is a polymer electrolyte membrane PEM water electrolyzer or a PEM fuel cell.