(Mg,Co)O Solid-Solution Precursors for the Large-Scale Synthesis of Carbon Nanotubes by Catalytic Chemical Vapor Deposition

摘要

Single- and double-walled carbon nanotubes were produced in high yield using the selective reduction of solid solutions of Mg1–xCoxO in a methane and hydrogen atmosphere at 1000°C. The solid solutions were prepared using combustion synthesis with urea as the fuel. The BET surface areas ranged from 10 to 65 m2/g depending on the fuel content. A single crystalline phase was obtained only for fuel-rich compositions. Increased fuel content increased the surface area by a factor of 6. However, very high fuel contents (>4 times the stoichiometric amount) caused a demixed solid solution. Surface-area measurements and Raman spectra showed that the quantity of nanotubes formed depended on the surface area and composition of the precursor oxide.