(290f) Stabilizing Effect of Sulfur Incorporation on Multi- and Single-Wall Carbon Nanotubes
We have successfully incorporated sulfur into both multi-wall and single-wall carbon nanotubes. Lawesson reagent has been used as a sulfurization agent. Post synthesis characterization revealed that sulfur incorporation stabilizes carbon nanotubes against temperature treatment and improves conductivity without damaging the structure. Controlled heteroatom incorporation alters electronic and physicochemical properties of carbon nanotubes facilitating nanodevice, catalytic or electrode applications. For example sulfur doped carbon nanotubes might be used as material for lithium ion cathodes or low-cost electrocatalyst in fuel cells. Raman spectroscopy data have shown that D band representing defects in the graphene structure of carbon nanotubes decreases significantly after incorporation, the Raman breathing modes (RBM) though shifted due to electronic change increase in intensity compared to nitric acid treated sample. TEM images confirm that carbon nanotubes stay intact after Lawesson treatment. The amount of incorporated sulfur has been investigated using temperature programmed oxidation and is approximately 6.3wt. %. Near edge X-ray absorption fine structure spectroscopy was used to study the local bonding energy of sulfur to understand the mechanism of sulfur incorporation into carbon nanotube structure.