Breakdown of diameter selectivity in a reductive hydrogenation reaction   of single-walled carbon nanotubes
  Reductive hydrogenation was applied to two types of single-walled carbon nanotubes with different diameter range. Alkali metal intercalation, followed by reaction with methanol, led to hydrogenated products. Both yield and selectivity of this reaction showed strong dependence on diameter, contrary to expectation based on simple curvature effects. The observed yield, as detected by thermogravimetry-mass spectroscopy and 1H-NMR, is drastically reduced in small-diameter tubes where the alkali dopant does not reach the inside of the bundles. Wide range optical transmission measurements were employed to determine the selectivity and indicate that besides higher yield, lower diameter selectivity occurs above a critical diameter. 
Katalin Nemeth, Emma Jakab, Ferenc Borondics, Hajnalka M. Tohati, Aron   Pekker, Monika Bokor, Tamas Verebelyi, Kalman Tompa...
cond-mat.mtrl-sci