Keyword: «nanodiamonds»

After heat treatment, the ratio of hydroxyl and carboxyl groups, according to IR spectra, both in samples of natural nanodiamonds and in nanodiamonds obtained by detonation synthesis, decreases. An increase in the amount of carboxyl groups on the surface of nanodiamonds after heat treatment in air indicates the oxidation of functional groups under experimental conditions. In the IR spectra of nanodiamonds after heat treatment, the bands in the absorption region of the diamond lattice become more distinguishable, which is explained by the partial purification of the diamond crystalline core from the graphite-like shell. In the IR spectra of natural nanodiamonds after heat treatment, bands appear in the absorption region of nitrogen defects of types A and B, which makes it possible to attribute the sample under study to type I-AB.