An XPS Study of Vacuum Ultraviolet Photo-oxidation of Carbon Nanotubes.
M. R. Rasmussen¹; D. D. Allred¹
1. Physics & Astronomy, Brigham Young, Provo, UT, USA.
 

Photo-oxidation of carbon nanotubes (CNTs) occurred with exposure to 172 nm vacuum ultraviolet (VUV) light from a xenon excimer lamp, in air. X-ray photoelectron spectroscopy (XPS) showed that after 15 min. of oxidation, nearly 45% of the carbon atoms were functionalized into ether, carbonyl, and carboxyl groups (identified by curve-fitting of the C 1s peak). In spite of the high level of oxidation, the CNTs did not deteriorate; their structure was maintained when viewed by scanning electron microscopy (SEM). Functionalizing CNTs is faster with VUV exposure than with UV/ozone oxidation due to higher energy photons (7.2 eV) affecting photo-oxidation and creating atomic oxygen; VUV exposure is also advantageous over acidic oxidation because it creates no liquid waste.