Sulfur-modified cobalt catalysts for the chirality-selective synthesis of single-walled carbon nanotubes
Date of Issue2017-05-16
School of Chemical and Biomedical Engineering
Selective synthesis of single-walled carbon nanotubes (SWCNTs) with a specific (n, m) chirality is desired for many potential applications. A sulfur-assisted CVD method using ethanol as carbon feedstock was demonstrated. The results show that introducing sulfur-containing compounds into carbon feedstock dramatically influences the carbon yield, and alters the chirality selectivity. Moreover, a new sulfidized Co/SiO2 catalyst was prepared to synthesize SWCNTs. Co/SiO2 catalyst was first sulfided with the mixture of H2S and H2, and then, SWCNTs were grown by CVD using CO as carbon feedstock. The results indicate that the sulfided Co/SiO2 catalyst has a good selectivity to (9,8) nanotubes, without decreasing the carbon yield compared to original Co/SiO2 catalyst. The characterizations of the catalyst indicate that the formation of Co9S8 nanoparticles plays a critical role in modulating the chirality selectivity of the catalyst. A fluidized-bed reactor was designed, attempting to increase the production of SWCNTs.