Analysis of heat-treated graphite oxide by X-ray photoelectron spectroscopy

Spectral change of simulated X-ray photoelectron spectroscopy from graphene to fullerene

“…The peak maximum of C2 was lower than that of C1 in binding energy because hydrogen atoms donate electrons to carbon atoms of C2 (Fig. S4, SM) [21,22]. The peak maximum of C3 in graphene with two pentagons was at 283.4 eV (a dotted line in Fig.…”

“…However, we simulated the XPS spectra using only the initial state effect by applying the scaling factor to the spectra in this work because of the simplicity of this method with good correlation between actual and calculated results [21,22]. For simulating C1s spectra using the calculated binding energy, the scaling factor of 1.038, obtained from the actual value of graphite (284.0 eV from valence band edge) divided by the calculated value of graphene terminated with hydrogen atoms (273.7 eV from HOMO level), was multiplied to all of the calculated binding energies to compensate for the difference between the calculated and the actual binding energies instead of the application of the final state effects.…”

“…Our group has demonstrated the effects of defects such as functional groups and STW defects on FWHMs and shifts of XPS spectra [21,22]. Electron-withdrawing groups such as C=O and C-CN have large effects on shifts as well as FWHMs of main peaks consisting of sp 2 C-sp 2 C. Pentagons have a similar role to C=O and C-CN because of their electron-withdrawing nature [23].…”

“…Since Proctor and Sherwood [13] as well as Boutique et al [14] have started computational analyses of functional groups on carbon materials in the 1980s, several groups have reported assignments of defective structures of graphene-related materials using calculation [15][16][17][18][19][20]. Until the present, XPS analysis of pentagons on graphene has not been reported except three papers [12,20,21] to the best of our knowledge. For example, point defects including one pentagon in graphene have been analyzed and the peak originating from the pentagon was shifted to -0.8 eV from a peak originating from carbon atoms on hexagons [12].…”

Effects of alkali-oxygen oxidation temperature on the structures and combustion properties of Shengli lignite

“…The C1s spectra demonstrated the presence of ve carbon species on the surface of coal samples, which were aromatic units with their alkyl substituent groups (C-C/C-H, 284.6 eV), vacancy defects on functional groups (C*-C*, 285.3 eV), hydroxyl or ether group (C-O-, 286.3 eV), carbonyl (C]O, 287.6 eV), and carboxyl (COO-, 289.1 eV), respectively. 30,31,54,55 Table 4 summarized the relative amounts of different C species on lignite surface.…”