XPS peak analysis of SD- and S-ACs.
| Sample | Content (at%) | N/C ratio (%) | Relative N1s peak areaa (at%) | |||||
|---|---|---|---|---|---|---|---|---|
| C | O | N | N-6 | N-5 | N-Q | N-X | ||
| S-AC | 90.6 | 7.7 | 1.7 | 1.82 | 0.41 | 0.72 | 0.40 | 0.17 |
| SD1.5 | 86.7 | 9.7 | 3.6 | 4.15 | 0.87 | 1.98 | 0.58 | 0.17 |
| SD1.75 | 87.6 | 8.2 | 4.2 | 4.79 | 1.03 | 2.34 | 0.72 | 0.11 |
| SD2 | 88.4 | 7.0 | 4.6 | 5.20 | 1.10 | 2.58 | 0.87 | 0.05 |
Pyridine N (N-6), pyrrolic N (N-5), quaternary N (N-Q) and oxidized pyridine N (N-X).