Dispersed detonation nanodiamonds have been studied by continuous-wave (CW) and pulse EPR techniques. The spectrum of bulk radicals (g = 2.0025 ± 0.0002, a Lorentz line shape with ΔH pp = 0.95 ± 0.05 mT) dominated in CW EPR and prevented to record spectra from other paramagnetic species. The pulse EPR spectrum was the superposition of the distorted P1-center spectrum with parameters (g = 2.0025, A xx = 2.57 mT, A yy = 3.08 mT, A zz = 4.07 mT), the H1-center spectrum (g = 2.0028) and the single line (g = 2.0025, ΔH pp = 0.40 ± 0.05 mT) from other centers which may be assigned to surface radicals. The concentration of P1-centers has been estimated by CW EPR as 2 ± 1 ppm N.

A comparative study of the effect of ozonization on the physicochemical properties of naturally and synthetically generated nanocarbon materials, shungite carbon (ShC) and ultra-disperse diamond (UDD) after special treatment in the form of monodisperse single nano-diamond particulates (mdsn-D), that have a similar two-level structural pattern (hierarchical system structure) and curved graphene shells or their fragments contribute to the formation of the structure and surface properties of both ShC and mdsn-D particles, was conducted. The ozonization kinetics of ShC and mdsn-D showed their high catalytic activity during ozone decomposition. Upon ozonization, the graphene shell is removed selectively from the surface of the diamond core of mdsn-D, as shown by Fourier transform-infrared (FT-IR) spectroscopy and derivatography data. A distinctive characteristic of ShC is a substantial change in structural parameters upon ozonization: structural porosity increases and the size of coherent scatter domains decreases in the direction perpendicular to graphene layers [as shown by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) data], which agrees with adsorption experiments that showed an increase in ultramicroporosity and mesoporosity upon ozonization of ShC. The molecular probe technique was used to monitor changes in microporosity of ShC and mdsn-D.

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