Tomic concentration appears to be reached at higher 5.two temperatures (3.6.0 at. 800 five.1 1.five).900 five.0 1.4 Table
Tomic concentration seems to be reached at high 5.two temperatures (three.six.0 at. 800 five.1 1.5).900 five.0 1.4 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 .5 at . 950 4.0 1.three Argon 850 3.six 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 .5 at. .Initial VacuumIn order to gain further 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 five.7 1.six Supplementary Materials (Figure S1). It corresponds to DND annealed at 950 C beneath 850 five.3 1.three argon. Following a (-)-Irofulven web background Shirley correction, distinctive elements happen to be regarded as 900 6.1 1.2 to fit this spectrum. The sp3 carbon 1 at 285.four eV was taken as reference, reflecting 2 carbon is downshifted at -1 eV [48]. Its intrinsic diamond. The element connected to sp 950 five.two 1.Temperature COxygen at.Nitrogen at.Argon800 8505.1 3.6 five.1.five 1.five 1.Nanomaterials 2021, 11,9 ofasymmetry, linked to its conductor GYKI 52466 web character, was taken into account in the fit (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 incorporates sp3 C neighboring structural defects generally present in detonation ND, carbon partially saturated with hydrogen (in the surface and in the core of your particle) and carbon bounded to a nitrogen atom [31,48]. Elements assigned to ether (C), C=O, and carboxyl (COOH) bonds are also present at higher binding energies, situated, respectively, at +1.9, +3 and +4 eV from sp3 carbon [49]. All C1s spectra had been fitted making use of these six elements. Percentages of total carbon for every component are reported on Figure 4c,d for both annealing atmospheres. On initial DND, the element related to defective sp3 C , CHx and C bonds represents 53 of 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 (six ) although a compact sp2 -C is detected (3.5 ). What ever the annealing atmosphere, the C1s spectrum undergoes powerful modifications right after the initial annealing at 800 C. Indeed, 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 with the distinctive carbon-oxygen groups, this decrease is in very good agreement using the decrease on the oxygen atomic concentration (Table 1) and FTIR observations, considering that adsorbed water may perhaps also participate towards the oxygen content. The sp3 -C contribution arises (401 ) as well as the component assigned to defects, CHx and C bonds is reduced (42 and 46 for vacuum and argon, respectively) even though a slight improve of sp2 -C is measured (four.5 ). A reorganization with the C bonds appears to occur, that is more probably resulting from surface desorption of carbon-oxygen functions but can also be explained by a migration of vacancies contained within the diamond core as much as the surface, as it is well-known inside the field of NV centers synthesis for such temperature [50]. For vacuum annealing, the sp2 -C element is growing to 7.five at 850 C, whereas it rises to 30 at 900 C. With regards to the a part of defects, CHx and C.
