Kinetics of 3He, 4He, H2, D2, Ne, and N2 sorption by bundles of single-walled carbon nanotubes. Quantum effects

Abstract

This is a study of the low temperature kinetics of the sorption and subsequent desorption of 3He, 4He, H2, D2, Ne, and N2 by bundles of single-wall carbon nanotubes with closed ends (c-SWNT). The characteristic times of the sorption and desorption processes are the same to within the experimental error. Annealing a sample of bundles at 500 °C greatly reduces the characteristic times and changes their temperature dependences. The effect of annealing decreased with increasing molecular weight of the dissolved gas. At temperatures below 16 K the sorption times for 3He, 4He, H2, and D2 depends weakly on temperature, which suggests a tunnel character of the sorption for these impurities by nanotube bundles. The effect of γ-irradiation of nanotube bundles on the sorption and desorption of hydrogen is qualitatively similar to the effect of annealing.