Abstract

X-ray photoelectron spectroscopy data confirm that the surfaces of detonation-diamond particles contain complexes consisting of nitrate ions bound to surface defects of substitutional nitrogen in the diamond lattice or to structural units of type C(sp³)–NH3+ on the surface. Etching with argon ions easily removes the nitrate-ion complexes from the surface of the detonation diamonds without damaging their crystal lattice. Analysis of a sample’s IR absorption spectra before and after thermal heating at 350°C makes it possible to distinguish on the spectrum two lines (narrow and wide) with close-lying frequencies (1384.9 and 1372  cm⁻¹), caused only by the different degree of bonding of the nitrate ions to underlying surface sites that contain nitrogen in tetrahedral sp³ coordination. The narrow line with higher peak intensity corresponds to an almost quasi-free state of an isolated nitrate ion on the surface of the detonation diamonds in the composition of a complex already damaged during moderate heating or during other low-energy treatments. Detonation-diamond particles with chemisorbed nitrate ions are unique markers that allow themselves to be easily detected in solid deposits of suspensions and solutions.

© 2018 Optical Society of America