# US 7,608,556 B2 · Carbon nanotubes as catalysts in redox reactions

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- Number: US 7,608,556 B2
- Document ID: US7608556B2
- Status: Granted
- Kind: B2
- Application number: 12/169,063
- Filed: 2008-07-08
- Published: 2008-11-06
- Granted: 2009-10-27
- Earliest claimed: 2004-03-02
- Assignees: E. I. Du Pont de Nemours and Company
- Inventors: Bruce A. Diner; Ming Zheng
- Web page: https://patentgrep.com/patent/US7608556B2

## CPC

- D01F 11/10: of carbon
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- D01F 11/12: with inorganic substances {; Intercalation}
- D01F 11/14: with organic compounds, e.g. macromolecular compounds
- D01F 11/16: by physicochemical methods
- H01G 9/20: Light-sensitive devices
- H01G 9/2031: {comprising titanium oxide, e.g. TiO2 (H01G9/2036 takes precedence)}
- H01M 8/20: Indirect fuel cells, e.g. fuel cells with redox couple being irreversible (H01M8/18 takes precedence)
- H01M 14/005: {Photoelectrochemical storage cells (light sensitive devices H01G9/20, semiconductors sensitive to light H10F)}
- H10K 85/221: {Carbon nanotubes}
- H10K 85/615: {Polycyclic condensed aromatic hydrocarbons, e.g. anthracene}
- Y02E 10/542: Dye sensitized solar cells
- Y02E 10/549: Organic PV cells
- Y02E 60/50: Fuel cells
- Y10S 977/704: Nucleic acids, e.g. DNA or RNA
- Y10S 977/742: Carbon nanotubes, CNTs
- Y10S 977/745: having a modified surface
- Y10S 977/746: Modified with biological, organic, or hydrocarbon material
- Y10S 977/842: for carbon nanotubes or fullerenes
- Y10S 977/847: Surface modifications, e.g. functionalization, coating
- Y10S 977/895: having step or means utilizing chemical property
- Y10S 977/902: Specified use of nanostructure
- Y10S 977/948: Energy storage/generating using nanostructure, e.g. fuel cell, battery
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Carbon nanotubes have been reversibly and readily oxidized and reduced with common chemicals in solution, thereby allowing the nanotubes to be used as catalysts for chemical reactions and as stable charge storage devices.

## Claims

### Claim 1

A process to catalyze a redox reaction comprising: contacting at least one carbon nanotube in solution with:
a) an oxidizing agent and an oxidizable compound or
b) a reducing agent and a reducible compound wherein the redox reaction is catalyzed.

### Claim 2 (depends on 1)

The process of claim 1 wherein the oxidizing agent is selected from the group consisting of 2,3-dichloro-5,6-dicyano-p-benzoquinone, benzoyl peroxide, chloranil, chlorine, dichlorodicyanobenzoquinone, dichlorodicyano-p-benzoquinone, diphenylbenzoquinone, divalent chromium, formate, glucose, hexachloroiridate, hydrogen peroxide, hydroperoxide, hyperchlorous, hypophosphite, iodine,naphthoquinone, N-bromosuccinimide, N-chlorosuccinimide, N-iodosuccinimide, nitrate, nitric acid, nitrous acid, o-benzoquinone, o-chloranil, o-iodobenzoate, oxygen, ozone, p-benzoquinone, p-chloranil, peracetic acid, perborate, perboric acid, perchlorate, perchloric acid, permanganate, permanganic acid, peroxide, peroxyacids, perphosphoric acid, persulfate, persulfuric acid, pertitanate, pervanadate, p-toluquinone, ribose, saccharose, perforate, stannous, stilbenequinone, sulfite, sulfur, sulfuric acid, tetrathionate, trivalent titanium, and trivalent vanadium.

### Claim 3 (depends on 1)

The process of claim 1 wherein the reducing agent is selected from the group consisting of 9,10-diphenylanthracene radical anion, acid chlorides, acridine anion, alkali metal sulfates, aluminum sulfates, anthraquinol, benzophenone anion, bisulfite, boranes, borates, carbon monoxide, chromium(II) salts, diimine, dithionite, formic acid, Group I & II metals, hydrazine, hydrides, hydrogen, hydrosulfite, iron(II) salts, lithium aluminum hydride, low-valence titanium ions, naphthalene radical-anion, nitrous acid, N-n-butylphthalimide anion, niobium(III) salts, perylene radical anion, phenanthridine radical-anion, phosphates, phosphines, phthalonitrile anion, polyphosphates, reducing sugars, sodium borohydride, sulfides, thiosulfate, thiourea, transition metals, trans-stilbene anion, and vanadium(II) salts.

### Claim 4 (depends on 1)

A process according to claim 1 wherein the carbon nanotube is selected from the group consisting of single walled nanotubes and multiwalled nanotubes.

### Claim 5 (depends on 1)

A process according to claim 1 wherein the carbon nanotube is in the form of nanotube ropes.

### Claim 6 (depends on 1)

A process according to claim 1 wherein the carbon nanotube is in the form of dispersed nanotubes.

### Claim 7 (depends on 1)

A process according to claim 1 wherein the carbon nanotube is associated with a dispersant or a mixture of disperants.

### Claim 8 (depends on 7)

A process according to claim 7 wherein the dispersant is negatively charged.

### Claim 9 (depends on 7)

A process according to claim 7 wherein the dispersant is positively charged.

### Claim 10 (depends on 7)

A process according to claim 7 wherein the dispersant is uncharged.

### Claim 11 (depends on 7)

A process according to claim 7 wherein the dispersant is a nucleic acid.

### Claim 12 (depends on 7)

A process according to claim 7 wherein the dispersant is a detergent.