Table 3. Assignment of the C 1s components of the high resolution XPS spectra.
| Component | BE (eV) | Assignment |
|---|---|---|
| C(1) | 284.3 ± 0.1 | Graphitic carbon |
| C(2) | 284.9 ± 0.1 | Non-conjugated carbon |
| C(3) | 286.0 ± 0.1 | C–O, as phenols or ethers, C sp3 bound to nitrogen (-CH2-CH2-N<) |
| C(4) | 287.0 ± 0.2 | C=O, of ketones and quinones, C=N, imines |
| C(5) | 288.3 ± 0.2 | N-C=O, carboxamide groups, O-C=O, carboxylic derivatives as carboxylic acids, ethers and anhydrides |
| C(6) | 290.6 ± 0.4 | Shake-up |
| C(7) | 289.4 ± 0.1 | -(O)C-N-C(O)-, carbons of imides taking part of 5 member cycles |