Table 1 Surface composition (at%) and relative distribution of surface groups (abundance, %) obtained upon Deconvolution of the XPS data corresponding to the C1s, O1s and N1s core energy levels of the prepared samples.
Surface Composition (at%) | CD-10 | CD-20 | CD-30 | CD-40 | |
|---|---|---|---|---|---|
Carbon | 73.00 | 73.90 | 73.30 | 73.10 | |
Oxygen | 23.70 | 21.40 | 23.20 | 21.90 | |
Nitrogen | 3.30 | 4.70 | 3.50 | 5.00 | |
Relative distribution of surface groups (abundance, %) | |||||
Binding Energy [eV] | CD-10 | CD-20 | CD-30 | CD-40 | |
Carbon C1s core level | |||||
C sp2 | 284.6 | 35.91 | 41.80 | 47.67 | 50.98 |
C sp3 | 285.0-285.1 | 25.14 | 22.99 | 19.07 | 15.29 |
C = N | 285.3-285.6 | 10.75 | 7.11 | 6.20 | 5.35 |
C-N/C-O | 286.1-286.4 | 1.04 | 1.58 | 1.62 | 2.11 |
O = C-N/O-C = O | 288.7-288.9 | 20.40 | 20.03 | 19.00 | 19.85 |
π-π* shake-up | 291.2-291.4 | 6.75 | 6.49 | 6.44 | 6.42 |
Oxygen O1s core level | |||||
O = C | 531.7-531.9 | 58.49 | 62.61 | 64.87 | 66.01 |
O-C | 533.3-533.5 | 41.51 | 37.39 | 35.13 | 33.99 |
Nitrogen N1s core level | |||||
Imine | 398.7-398.9 | 16.30 | 17.19 | 23.87 | 15.85 |
Pyrrolic/Pyridonic | 400.1-400.3 | 57.22 | 57.88 | 68.19 | 70.04 |
N-quaternary/Protonated amine | 401.1-401.5 | 26.48 | 24.93 | 7.95 | 14.10 |
