Lubos Jankovic

Formation of carbon nanotubes on iron/cobalt-modified zeolites: Effect of zeolite framework/pore structure and method of modification

The present study focuses on the effect of the metal-modification method (ion-exchange or impregnation) and of the type of dealumination procedure (steaming, AHFS) of zeolite-Y on the quantity, quality and properties of the carbon nanotubes that are formed on the supported iron or cobalt oxides. Severe dealumination of zeolite-Y by steaming, which induced secondary meso/macropores, resulted in significant decrease in the carbon nanotube formation activity of the metal-impregnated zeolite-Y catalysts, while moderate dealumination by ammonium hexafluorosilicate had a less pronounced effect. The micro-Raman spectra revealed the presence of high quality as-grown CNTs with low degree of disordered.

Catalytic production of carbon nanotubes over first row transition metal oxides supported on montmorillonite

Clay-carbon nanotube composites were prepared by employing the catalytic chemical vapor deposition method (CCVD) over different transition metal oxides supported on montmorillonite. Various analytical techniques including SEM, TEM, XRD and DTA/TGA were used for the characterization of the final composite materials. The morphology, quality and structure of the produced nanotubes is shown to be dependent on the type of transition metals.