With their well-defined pore structure and chemical composition, vertically aligned carbon nanotubes (VACNTs) offer the possibility for a combined theoretical and experimental investigation of their gas adsorption behavior. Due to their nearly ideal 1D structure they offer a defined morphology in which a variety of structural parameters can be tailored. Subsequently the influence of curvature, packing density, adsorption site topology, inner and outer adsorptive surface as well as the influence of functional groups/heteroatoms on CO2 adsorption characteristics can be studied. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim