FTIR study of ultradispersed diamond powder synthesized by explosive detonation

Ultradispersed diamond (UDD) powders synthesized by explosive detonation were studied by FTIR to explore their surface functional groups. Deconvolution and second derivative spectra and curve fitting techniques were used to ascertain the frequencies of functional groups. Samples after oxidation by two kinds of mixed acid and after reduction in hydrogen were investigated. Experimental results indicated that several types of carbonyl groups are predominant on the surface of UDD, the contents of which are related to the methods of acid treatment. The main reactions of hydrogen treatment are the conversion of carbonyl groups to hydroxyls, and further to C-H bonding. After reoxidation of the hydrogen treated samples, the spectra recovered to their original levels, which indicated that reduction reactions of the surface functional groups are reversible.