SYNTHESIS OF CARBON NANOTUBES BY CATALYTIC CVD USING Fe-Mo/MgO AND Fe-Mo/Al_2O_3 CATALYSTS

摘要

Carbon nanotubes (CNTs) were synthesized by catalytic chemical vapor deposition using Fe-Mo/MgO and Fe-Mo/Al_2O_3 catalysts. Methane was used as the carbon source. The catalysts were prepared by impregnating MgO or Al_2O_3 catalyst support with a Fe-Mo solution. Two different iron sources, Fe(NO_3)_3 and Fe_2(SO_4)_3, were used to prepare the catalyst. Experimental results indicate that addition of molybdenum favors the formation of CNTs and that the growth temperature is lower when Fe_2(SO_4)_3 is used as the iron source. SEM observations show that large quantities of entangled CNT bundles with a layer network morphology can be synthesized and that very small amount of amorphous carbon is observable. Under optimum growth condition, compacted CNT bundles of several micrometers in length, protruded out of the catalyst surface, can be grown and the yield can be increased significantly. Most of the CNT products are double-walled CNTs by TEM observations.