Keyword: «carbon structure»

The effect of thermal treatment on the Raman spectra of detonation nanodiamonds was investigated in comparison with those of natural nanodiamonds. It was found that annealing in air at 430–550 °C leads to the appearance of a distinct diamond peak at 1328 cm⁻¹ and a decrease in the intensity of disordered carbon bands. Thermal treatment reduces the fraction of sp²-hybridized carbon atoms and improves the stability of nanodiamond particles in aqueous suspensions.

The detonation and natural nanodiamonds were investigated using nuclear magnetic resonance (NMR) spectroscopy before and after thermal treatment. The NMR spectra of the initial samples revealed signals from sp³- and sp²-hybridized carbon atoms corresponding to the diamond core and disordered carbon shell. Thermal annealing at 550 °C leads to a decrease in non-diamond sp² carbon and changes in the surface functional groups. The results confirm the effectiveness of thermal purification of nanodiamonds.