Unexpected effect of CNT exfoliation on adsorption kinetics of small organic molecules bundles vs. isolated carbon nanotubes

By means of an ultra-high vacuum kinetics technique, we show unexpected experimental evidence that a thick layer of carbon nanotubes (CNTs) shows a kinetically distinct adsorption behavior than thin monolayer CNT films. Thick layers reveal much greater desorption temperatures (binding energies) for n-pentane and benzene as compared to thin CNT films. These results are significant for applications in catalysis since greater binding energies lead to greater surface densities of reactants promoting surface reactions. Furthermore, in order to address the effect of CNT crystal structure on chemical activity HiPco and CoMoCAT CNT samples have been characterized by studying benzene, n-pentane, methanol, and water adsorption.