Sp2 amorphous carbons in view of multianalytical consideration: Normal, expeсted and new

Abstract

sp2 Amorphous carbons are considered as objects of the modern nanotechnology. A particular set of the highest‑carbon-content sp2 species, two natural amorphous carbons (shungite carbon and antraxolite) as well as two engineered carbon blacks were subjected to analytical study by using a set of selected modern structural and compositional analytical techniques. The suggested approach occurred quite efficient and allowed disclosing a number of steady points that are common to the whole class of this carbon allotrope and are able to get a vision of atom-molecular representation of the solids. Among the commonalities observed, there are the following: i) sp2 Amorphous carbons are conglomerates of nanographites, basic structure units of which lay the foundation of the atom-molecular description of the solids. ii) The units represent framed graphene molecules of 1÷2 nm and of 1÷ (1÷3)*10 nm in size in the case of natural and engineered products, respectively. iii) The molecule framing, predominantly incomplete with respect to the number of vacant places, concerns only edge atoms and is implemented by the related chemical additives, such as hydrogen, oxygen, nitrogen, sulfur and halogens which are attached to the carbon core via chemical bonding. iv) Inelastic neutron scattering and X-ray photoelectron spectroscopy allow attributing the bonds to chemical compositions involving hydrogen and oxygen while quantum chemistry ensures reliable support. v) The basic structure units of sp2amorphous carbons are strongly radicalized due to which the latter acquire new properties, being the largest repository of stable radicals.