Hydroxylated Detonation Nanodiamond: FTIR, XPS, and NMR Studies

Detailed and unambiguous characterization of the surface structure of detonation nanodiamond (DND) particles remains one of the most challenging tasks for the preparation of chemically functionalized nanodiamonds. In the present paper, a combination of FTIR, NMR, and XPS was used to characterize DND particles that were treated in a reduction reaction that results in the enrichment of hydroxyl and hydroxymethyl functional groups. FTIR spectra and quantum-chemistry modeling demonstrated that the vacuum treatment of the sample, with the purpose of the removing adsorbed water and other volatile contaminates, is mandatory to obtain the correct data on the nature and relative content of the -OH surface groups on DND. C-13 and H-1 NMR spectra show signals from the diamond core, hydroxyl, hydrocarbon groups, and moisture on the diamond surface. NMR data were taken for as-prepared DNDs, as well as those that were dried under vacuum conditions of 10(-4) Torr, in order to distinguish between the NMR signal contributions due to moisture and other hydrogen-containing groups.