Selective Argon Uptake and Structural Ordering in Carbon Honeycomb Nanostructures.

This year marks the tenth anniversary of the experimental discovery and structural identification of carbon honeycomb (CH) structures. One of the most prominent properties of CHs is their unique high sorption capacity, which may play an important role in numerous applications, such as Li/Na batteries, hydrogen storage and carbon dioxide capture, as well as in the production of unique composites. In this paper we examine how atoms captured in CHs can be distributed inside CH channels using argon as a neutral probing material. Through a comprehensive structural analysis of the high-energy electron diffraction data, we demonstrate that argon atoms are not randomly positioned, but are rather arranged in specific clusters within the CH nanochannels. In the paper we propose two different original approaches to the structural analysis of pure and argon-filled CHs. We have also revealed that not all CH channels of various sizes are filled with argon, considering the spatial confinement in the thinnest channels to be one of the reasons for such a behavior. It was also found that external conditions may play an important role in filling CHs with gases, particularly at growing temperatures, when atoms gradually desorb, first from the channels of the largest sizes.