title: Surface area measurement of functionalized single-walled carbon nanotubes.
abstract: Single-walled carbon nanotubes have been functionalized and the specific surface areas of the functionalized nanotubes measured. Contrary to expectations, functionalization leads to a decrease in specific surface area compared to that of the unfunctionalized nanotubes. Treatment with a concentrated 1:1 nitric/sulfuric acid mixture followed by high-temperature baking at 1000 degrees C was found to increase the specific surface area of the nanotubes. For the unfunctionalized SWNTs, this treatment increases the specific surface area (SSA) by 20%. In the case of SWNTs functionalized by n-butyl groups the increase in the SSA was nearly 2-fold with the value increasing from 410 (drying at 110 degrees C) to 770 m2/gm (acid and bake treatment followed by drying at 110 degrees C). For the ozonized SWNTs, the SSA increases more than 3-fold from 381 (drying at 110 degrees C) to 1068 m2/gm (acid and bake treatment followed by drying at 110 degrees C). SEM images indicate that the nanotubes rebundle in the solid state with an average bundle size of 10-30 nm. AFM studies show that the ozonized tubes have been cut to short bundles after ozonolysis. Hydrogen uptake studies carried out on the baked ozonized tubes led to a 3 wt % hydrogen uptake at 77 K and 30 bar.
authors.affiliation: Department of Chemistry and The Richard E. Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77251, USA.
authors.forename: Soma
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Jayanta
authors.initials: J
authors.lastname: Chattopadhyay
authors.forename: Haiqing
authors.initials: H
authors.lastname: Peng
authors.forename: Zheyi
authors.initials: Z
authors.lastname: Chen
authors.forename: Arnab
authors.initials: A
authors.lastname: Mukherjee
authors.forename: Rolf S
authors.initials: RS
authors.lastname: Arvidson
authors.forename: Robert H
authors.initials: RH
authors.lastname: Hauge
authors.forename: W E
authors.initials: WE
authors.lastname: Billups