Ultra-fine fibrous carbon and preparation method thereof

• US 20060002842A1
• Filed: 10/17/2003
• Published: 01/05/2006
• Est. Priority Date: 10/17/2002
• Status: Active Grant

• Current Assignee: VINATECH Co., Ltd.
• Original Assignee: Suntel Limited (Axiata Group Berhad)
• Inventors: Yoon, Seong Ho
• Granted Patent: US 7,470,418 B2
• Time in Patent Office: Days
• US Class Current: 423/447.200
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 2202/34 Length
• CPC Class Codes: C01B 2202/36 Diameter
• CPC Class Codes: C01B 32/162 characterised by catalysts
• CPC Class Codes: D01F 9/127 by thermal decomposition of hydrocarbon gases or vapours or other carbon-containing compounds in the form of gas or vapour, e.g. carbon monoxide, alcohols
• CPC Class Codes: D01F 9/1273 Alkenes, alkynes
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2915 including textile, cloth or fabric
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/292 In coating or impregnation

Abstract

The present invention discloses ultra-fine fibrous carbon and preparation of the same. Specifically, the present ultra-fine fibrous carbon is characterized by the graphite-like structure with the sp² hybrid carbon content of more than 95% per total content; the (002) plane interlayer spacing (d_002, d-spacing of C(002) profiles determined by X-ray diffraction method) of 0.3370-0.3700 nm; the (002) plane stacking of more than 4 layers, namely the stacking height (Lc002) of more than 1.5 nm; fibrous carbon length per fibrous carbon width of diameter (aspect ratio) of more than 20; the average diameter of 5˜50 nm.

Claims

1. An ultra-fine fibrous carbon characterized by stacking of carbon hexagonal planes having one or double directional growth axis,

wherein (1) carbon content is more than 95 wt %;

(2) the diameters range from 3.5 to 79.9 nm;

(3) the aspect ratio (length per diameter) is more than 20; and

(4) the carbon hexagonal planes align perpendicular to the fiber axis with no continuous hollow core therein.

4. A method for producing a fibrous carbon of claim 1, characterized by the steps of using carbon black-supported metal mixture or alloy catalysts, wherein the metal mixtures or alloys involve nickel as a major catalyst, and iron or molybdenum as secondary metals;

the carbon black is characterized by less than 100 m²/g BET-surface area, 20˜

60 nm particle size, and more than 10 wt % oxygen content; and

the carbon black-supported catalyst contains 0.1˜

60 wt % metal mixture or alloy per carbon black; and

of the carbon source being introduced at the flow rate of 0.5˜

40 sccm per 1 mg catalyst in the furnace, where the carbon source involves hydrocarbons containing 2˜

6 carbon atoms or mixtures of aforementioned hydrocarbons and hydrogen.

6. A method according to claim 4, wherein

the hydrogen partial pressure in the mixture of hydrocarbons and hydrogen is selected between 0˜

80 v/v %;

the production temperature is selected between 300˜

499°

C.; and

the production time is selected between 2 min˜

12 h.

8. A method according to claim 4, whereby

the carbon black-supported catalyst is alternatively treated as follows:

oxidation to contain less than 1 wt % carbon black at 300˜

500°

C. in oxidative gas containing 5˜

40 v/v % oxygen or carbon dioxide in inert gases such as nitrogen, argon or helium; and

repetitive reduction by 1˜

3 times in gas mixtures of 5˜

40 v/v % hydrogen in nitrogen, argon or helium at 400˜

500°

C. for 1˜

48 h.

10. A method according to claim 8, wherein

said alloy according to the alloy kind is composed of 0.1/0.9˜

0.95/0.05(wt/wt) of Ni/Fe;

0.05/0.95˜

0.95/0.05(wt/wt) of Ni/Co; and

0.1/0.9˜

0.9/0.1(wt/wt) of Ni/Mo.

2. (canceled)

3. An ultra-fine fibrous carbon characterized by stacking of carbon hexagonal planes having one or double directional growth axis, wherein

(1) carbon content is more than 95 wt %;

(2) the diameters range from 3.5 to 79.0 nm;

(3) the aspect ratio (length per diameter) is more than 20; and

4 the carbon hexagonal planes align having 5˜

65°

angle to the fiber axis with no continuous hollow core therein.

5. A method for producing a fibrous carbon of claim 3, characterized by the steps of using carbon black-supported metal mixture or alloy catalysts, wherein the metal mixtures or alloys involve nickel as a major catalyst, and iron or molybdenum as secondary metals;

the carbon black is characterized by less than 100 m²/g BET-surface area, 20˜

60 nm particle size, and more than 10 wt % oxygen content;

the carbon black-supported catalyst contains 0.1˜

60 wt % metal mixture or alloy per carbon black; and

of the carbon source being introduced at the flow rate of 0.5˜

40 sccm per 1 mg catalyst in the furnace, where the carbon source involves hydrocarbons containing 2˜

6 carbon atoms or mixtures of aforementioned hydrocarbons and hydrogen.

7. A method according to claim 5, wherein

the hydrogen partial pressure in hydrocarbons and hydrogen mixtures is selected between 0˜

80 v/v %;

the production temperature is selected between 300˜

499°

C.; and

the production time is selected between 2 min˜

12 h.

9. A method according to claim 5, wherein

the carbon black-supported catalyst is alternatively treated as follows:

oxidation to contain less than 1 wt % carbon black at 300˜

500°

C. in oxidative gas containing 5˜

40 v/v % oxygen or carbon dioxide in inert gases such as nitrogen, argon or helium; and

repetitive reduction by 1˜

3 times in gas mixtures of 5˜

40 v/v % hydrogen in nitrogen, argon or helium at 400˜

500°

C. for 1˜

48 h.

11. A method according to claim 9, wherein

said alloy according to the alloy kind is composed of 0.1/0.9˜

0.95/0.05(wt/wt) of Ni/Fe;

0.05/0.95˜

0.95/0.05(wt/wt) of Ni/Co; and

0.1/0.9˜

0.9/0.1(wt/wt) of Ni/Mo.