Tomic concentration appears to be reached at high 5.2 temperatures (three.six.0 at. 800 5.1 1.5).900 five.0 1.4 Table
Tomic concentration seems to become reached at high 5.2 temperatures (3.6.0 at. 800 5.1 1.five).900 five.0 1.4 Table 1. Oxygen and nitrogen atomic concentrations determined by XPS for initial and annealed DND for each atmospheres. The uncertainty on concentration is estimated to .five at . 950 four.0 1.3 Argon 850 3.6 1.Table 1. Oxygen and nitrogen atomic concentrations determined by XPS for initial and annealed DND for both atmospheres. The uncertainty on concentration is estimated to .five at. .Initial VacuumIn order to get additional insights into the carbon chemistry of annealed DND, systematic 1.9 deconvolution of the C1s core levels of 9.3 sample was performed. A common C1s core each level spectrum is presented on Figure 4b. Other fitted C1s core levels are provided in 800 5.7 1.6 Supplementary Materials (Figure S1). It corresponds to DND annealed at 950 C under 850 five.three 1.3 argon. Right after a background Shirley correction, unique components happen to be regarded as 900 six.1 1.2 to match this spectrum. The sp3 carbon one at 285.4 eV was taken as reference, reflecting 2 carbon is downshifted at -1 eV [48]. Its intrinsic diamond. The component related to sp 950 five.2 1.Temperature COxygen at.Nitrogen at.Argon800 8505.1 three.six five.1.five 1.5 1.Nanomaterials 2021, 11,9 ofasymmetry, linked to its conductor character, was taken into Compound 48/80 site account within the match (Figure 4b). With an upshift of +1 eV from sp3 carbon, a third element is assigned to take into account all carbon atoms not linked to an oxygen atom. This involves sp3 C neighboring structural defects AAPK-25 manufacturer generally present in detonation ND, carbon partially saturated with hydrogen (at the surface and within the core with the particle) and carbon bounded to a nitrogen atom [31,48]. Components assigned to ether (C), C=O, and carboxyl (COOH) bonds are also present at greater binding energies, positioned, respectively, at +1.9, +3 and +4 eV from sp3 carbon [49]. All C1s spectra have been fitted working with these six components. Percentages of total carbon for every component are reported on Figure 4c,d for both annealing atmospheres. On initial DND, the component related to defective sp3 C , CHx and C bonds represents 53 from the total carbon at C1s. Components linked to carbon-oxygen bonds are also preeminent, all with each other at 37 . The sp3 -C contribution is weak (6 ) while a tiny sp2 -C is detected (3.5 ). Whatever the annealing atmosphere, the C1s spectrum undergoes robust modifications following the initial annealing at 800 C. Certainly, the contributions of C , C=O, and COOH bonds drop from 37 to 9 (argon) and 13 (vacuum) of total carbon. Thinking about the stoichiometry from the diverse carbon-oxygen groups, this reduce is in great agreement using the lower in the oxygen atomic concentration (Table 1) and FTIR observations, contemplating that adsorbed water may also participate to the oxygen content material. The sp3 -C contribution arises (401 ) along with the component assigned to defects, CHx and C bonds is decreased (42 and 46 for vacuum and argon, respectively) even though a slight boost of sp2 -C is measured (4.5 ). A reorganization on the C bonds seems to occur, which is far more most likely as a consequence of surface desorption of carbon-oxygen functions but may also be explained by a migration of vacancies contained inside the diamond core as much as the surface, since it is well known within the field of NV centers synthesis for such temperature [50]. For vacuum annealing, the sp2 -C element is rising to 7.five at 850 C, whereas it rises to 30 at 900 C. Regarding the a part of defects, CHx and C.
