Lemesh N. Effect of the condition of the heterogeneous catalytic synthesis of carbon nanotubes on their physical-chemical properties

The thesis is devoted to the relationship between the heterogeneous catalytic synthesis conditions and diameters, morphology of carbon nanotubes (CNT) obtained from ethylene on Ni, Co, Fe nanoparticles deposited on various supports, development of methods of CNTs synthesis with certain values of diameters, morphology and purity, which approximate to 100 %, so the identification of adsorption and catalytic properties of CNT in the reactions of dehydrogenation and dehydration of alcohols. It is shown that CNTs formation with different morphology and diameters depends on the nature of the support and metal. The application of catalysts prepared by co-precipitation method leads to the synthesis of CNTs with narrower diameter distribution and smaller contaminated of the other forms of carbon compared with CNTs obtained on impregnated catalysts. It is specified by the strong interaction between the metal and the support in case of co-precipitation catalysts due to the formation of mixed oxides. It is shown that metal nanoparticles size determines internal diameters of CNTs by implementation of the "base-growth" mechanism of CNTs growth. If CNTs are formed by "tip-growth" mechanism, the size of the metal nanoparticles determines external diameters of them.It was found that the synthesis temperature, concentration of C2H4, H2 and H2O in the gas mixture don't effect on their morphology and diameters distribution. The СNTs exhibit close activity and act simultaneously as acid-base and red-ox catalysts in the processes of dehydrogenation and dehydration of ethyl and isopropyl alcohols.