# US 2015/0147263 A1 · Carbon nanotubes and production method thereof

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- Number: US 2015/0147263 A1
- Document ID: US20150147263A1
- Status: Published application
- Kind: A1
- Application number: 14/409,500
- Filed: 2013-06-20
- Published: 2015-05-28
- Earliest claimed: 2012-06-22
- Assignees: The University of Tokyo; Hitachi Chemical Company, Ltd.
- Applicants: The University of Tokyo; Hitachi Chemical Company, Ltd.
- Inventors: Suguru Noda; Zhongming Chen; Dong Young Kim; Shunsuke Ueda; Eisuke Haba
- Web page: https://patentgrep.com/patent/US20150147263A1

## CPC

- B01J 21/02: Boron or aluminium; Oxides or hydroxides thereof
- B01J 21/06: Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
- B01J 21/18: Carbon
- B01J 23/745: Iron
- B01J 37/0238: {via the gaseous phase-sublimation}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- C01B 32/162: characterised by catalysts
- B01J 35/50: characterised by their shape or configuration
- 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
- 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
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}

## Abstract

The present invention relates to a method of producing carbon nanotubes, comprising a catalyst particle forming step of heating and reducing a catalyst raw material to form catalyst particles and a carbon nanotube synthesizing step of flowing a raw material gas onto the heated catalyst particles to synthesize carbon nanotubes, wherein a carbon-containing compound gas without an unsaturated bond is flowed onto the catalyst raw material and/or the catalyst particles in at least one of the catalyst particle forming step and the carbon nanotube synthesizing step.

## Claims

### Claim 1

A method of producing carbon nanotubes, comprising:
a catalyst particle forming step of heating and reducing a catalyst raw material to form catalyst particles, and
a carbon nanotube synthesizing step of flowing a raw material gas onto the heated catalyst particles to synthesize carbon nanotubes,
wherein a carbon-containing compound gas without an unsaturated bond is flowed onto the catalyst raw material and/or the catalyst particles in at least one of the catalyst particle forming step and the carbon nanotube synthesizing step.

### Claim 2 (depends on 1)

The method of producing carbon nanotubes according to claim 1, wherein the carbon-containing compound gas without an unsaturated bond is flowed onto the catalyst particles at least in the carbon nanotube synthesizing step.

### Claim 3 (depends on 1)

The method of producing carbon nanotubes according to claim 1, wherein the carbon-containing compound gas without an unsaturated bond is a saturated hydrocarbon gas.

### Claim 4 (depends on 3)

The method of producing carbon nanotubes according to claim 3, wherein the saturated hydrocarbon gas is methane.

### Claim 5 (depends on 1)

The method of producing carbon nanotubes according to claim 1, wherein the raw material gas contains acetylene or a gas generating acetylene in a reactor.

### Claim 6 (depends on 1)

The method of producing carbon nanotubes according to claim 1,
wherein the carbon-containing compound gas without an unsaturated bond is flowed onto the catalyst raw material and/or the catalyst particles at least in the catalyst particle forming step, and
the method further comprises a releasing step of releasing the catalyst particles from the heated state between the catalyst particle forming step and the carbon nanotube synthesizing step.

### Claim 7 (depends on 1)

Carbon nanotubes produced by the method of producing carbon nanotubes according to claim 1, wherein a ratio G/D determined by Raman spectroscopy is 10 or more.