|Title of Invention||
SYNTHESIS OF MULTI WALLED CARBON NANOTUBULAR COILS OVER ALLOY HYDRIDE CATALYST
|Abstract||A process for the synthesis of multiwalled carbon nanotubular coils comprising the deposition of Mm based alloy thin films over carbon fabric subsgtrate; preparation of fine powders of hydrides of the said films by hydrogen decrepitation; carrying out the catalytic decomposition of a hydrocarbon over the said hydrides at 700 degree C. in a single stage reaction furnace.|
This invention relates to synthesis of multi walled carbon nanotublar coils over alloy hydride catalyst, more particularly, though not exclusively, to such synthesis on a large scale.
In this invention, a novel product from the carbon family in the form of Multi Walled Carbon Nanotubular Coils (MWNTC) has been synthesized using alloy hydride thin film catalyst and acetylene as the carbon source. Thin film catalyst grown over carbon fabric by RF magnetron sputtering, was subjected to repeated cycles of hydrogenation/dehydrogenation using a high pressure Sieverts' apparatus. MWNTCs have been synthesized by the pyrolysis of acetylene using hydrogen decrepitated alloy hydride thin film catalyst. This process highlights the novel method of bulk synthesis of high pure MWNTC through a cost effective, simple process. The present invention also describes the process for the synthesis of Aligned Multi Walled Carbon Nanotubular Coils (AMWNTC) over alloy hydride catalyst.
This invention relates to the bulk synthesis of randomly oriented MWNTC and AMWNTC using a novel alloy hydride thin film catalyst. Due to their superior mechanical properties and low density, carbon fibers/nanotubes have been widely used in structural applications.
3D helical carbon materials are the focus of attention in academic research and their potential applications in nanocomposites, microelectronics, microelectromechanical systems (MEMS), bio MEMS, nano-electromechanical systems, nanosprings, electromagnetic wave absorbers, field emission displays' among others. There are three major types of 3D helical carbon material, ranging from micro- to nano-sizes, which are microcoiled carbon fibers, carbon nanocoils and coiled carbon nanotubes. Coiled carbon nanotubes exhibit excellent mechanical and electrical properties because of the combination of coil morphology and properties of nanotubes. As the properties of carbon nanotubular coils are expected to be dependent on the size and shape of catalytic particles, controlled growth of carbon nanotubular coils require an efficient route for catalyst preparation. The ease of separation and purification of carbon nanotubular coils varies with the catalyst and catalyst support used. Hence, there's a need for a simple, low-cost method of producing MWNTC using active metal catalysts that eliminates the need for extensive purification.
It is thus an object of the present invention for synthesizing MWNTC in bulk quantity, which employs the catalytic decomposition of a selected hydrocarbon over selected alloy hydride thin film materials.
The present invention employs a process wherein a selected hydrocarbon is catalytically decomposed over Mm based alloy hydride thin film. Alloy thin films are deposited on carbon fabric by reactive RF magnetron sputtering. The alloy hydride thin films are obtained by hydrogen decrepitation. MWNTC were synthesized by thermal chemical vapour deposition technique using a single stage furnace, by catalytic decomposition of acetylene over alloy hydride thin film catalyst at 700 °C. The present invention also>to the synthesis of AMWNTC by liquid assisted CVD (chemical vapour deposition). This invention is useful for the production of MWNTC in bulk quantities
for their applications in fuel cell technology and electronic devices.
MWNTC exhibit excellent mechanical and electrical properties because
of the combination of coil morphology and properties of nanotubes which
are potential candidates as catalyst support materials in fuel cells.
This invention uses selective Mm based alloy thin film hydride catalysts, which are of low cost and hence is a cost effective process tor the production of carbon nanotubular coils.
This invention which uses liquid assisted chemical vapour deposition helps in the production of well aligned multiwalled carbon nanotubular coils.
1. A process for the synthesis of multiwalled carbon nanotubular coils comprising the deposition of Mm based alloy thin films over carbon fabric substrate; preparation of fine powders of hydrides of the said films by hydrogen decrepitation; carrying out the catalytic decomposition of a hydrocarbon over the said hydrides at 700 degree C. in a single stage reaction furnace.
2. A process as claimed in Claim 1 wherein the said hydrides have
catalytically active surfaces.
3. A process as claimed in Claiml or Claim 2 wherein deposition of the
said film on carbon fabric substrate is carried out by magnetron
4. A process as claimed in claimed in Claim 1 or Claim 2 wherein
deposition of the said film on carbon fabric substrate is carried out by
liquid assisted chemical vapour deposition.
5. A process as claimed in any one of the preceding Claims wherein the hydrocarbon is acetylene.
6. A process for the synthesis of multiwalled carbon nanotubular coils
|Indian Patent Application Number||666/CHE/2007|
|PG Journal Number||42/2011|
|Date of Filing||30-Mar-2007|
|Name of Patentee||INDIAN INSTITUTE OF TECHNOLOGY|
|Applicant Address||IIT P.O CHENNAI 600 036|
|PCT International Classification Number||B32B9/00|
|PCT International Application Number||N/A|
|PCT International Filing date|