Incorporation of multiwalled carbon nanotubes in reduced graphene oxide aerogels for adsorptive separations of alkane vapours

Effect of the commercial multi-walled carbon nanotubes (MWCNTs), between 2 and 8 wt.%, on the structure of reduced graphene oxide aerogels (rGOAs) and adsorption of alkane vapours was discussed. The resulting composites (rGOA-MWNCTs) were characterised by scanning electron microscopy, Raman and Fourier-transform infrared spectroscopies and nitrogen adsorption. The adsorption of different alkane vapours (<i>n</i>-hexane,<i>n</i>-heptane,<i>n-</i>octane,<i>cyclo</i>hexane,<i>cyclo</i>octane and<i>iso</i>octane) was studied with inverse gas chromatography at finite concentration. Analyses revealed that addition of MWCNTs significantly changed the structure and surface properties of aerogels. Interestingly, deterioration of the porous structure was observed as the amount of MWCNTs increased. At the same time, MWCNTs enhanced the surface free energy of composites, compared to pristine aerogel. Alkanes vapours adsorption data indicate that pristine aerogel is the one with the highest adsorption capacity, but the isosteric heats of adsorption suggest that rGOAs with MWCNTs may be more selective in adsorption of alkanes, therefore more suitable for adsorptive separations.