CATALYSTS FOR THE LARGE SCALE PRODUCTION OF HIGH PURITY CARBON NANOTUBES WITH CHEMICAL VAPOR DEPOSITION

摘要

In the present invention, advanced catalysts for the production of high purity and high quality carbon nanotubes with the technique of chemical vapor deposition are described. The use of these catalysts and the described methodology allows the production of carbon nanotubes at high rates and with yields per mass unit of catalytic material, which are much higher than those achieved with other methods of carbon nannotubes production and other catalysts. The high yields, the high production rates and the very low cost of the catalysts that are employed in the developed method lead to the production of materials that cost much less than commercially available materials of similar or lower quality. The catalyst or the catalytic substrate on which carbon is deposited and grows in the form of nanotubes consists of the carrier or the substrate, which is aluminum oxide (alumina) or one of the other metal oxides that are usually employed as catalytic media, the active phase which is iron oxide (preferably hematite but also any other form) and a promoter, such as molybdenum oxide. The ratio of these three components plays a very important role in the composition of the catalyst.