Adsorption of Ferrocene on Carbon Nanotubes, Graphene, and Activated Carbon

Ferrocene could be adsorbed on activated carbon, carbon nanotube surfaces, graphite, and graphene in the absence of a solvent at room temperature in spite of its high melting point (174 degrees C). In each case only monolayers formed via self-adsorption and the transition to surplus polycrystalline material was abrupt, with no multiple layers occurring. Variable-temperature multinuclear solid-state NMR spectroscopy was applied to study the mobilities of the surface-adsorbed ferrocene molecules. It has been demonstrated that on favorable supports the major anisotropic interactions that usually broaden the solid-state NMR signals of polycrystalline and amorphous materials were reduced or completely eliminated due to the mobility of the adsorbed ferrocene. In favorable cases the chemical shift anisotropy (CSA) and the dipolar and quadrupolar interactions were reduced to a degree that allowed the recording of the spectra of the solid materials on a conventional solution NMR spectrometer.