Surface oxygen complexes as governors of neopentane sorption in multiwalled carbon nanotubes

Multiwalled carbon nanotube (MWCNT) samples were obtained by purification and ball-milling of a MWCNT sample synthesized by catalytic chemical vapor decomposition. These samples were oxidized with KMnO4–H2SO4 solution. A heat treatment was employed to decompose the oxygenated groups created by the oxidation treatment. The samples were characterized by transmission electron microscopy (TEM), adsorption of nitrogen, pore size distribution, and by thermogravimetric analysis combined with mass spectroscopy (TG-MS). The dynamics of 2,2-dimethyl-propane (neopentane) sorption was studied by frequency-response (FR) spectroscopy. The FR spectra obtained clearly demonstrate the effect of (a) the ball-milling, (b) the oxidative treatment and (c) the heat treatment on the sorption uptake processes involved in these treated samples.