XPS binding energies (BE), Full Width at Half Maximum (FWHM) and atomic percentages of C1s, O1s, Fe2p, Si2p and N1s core peaks for Fe NPs and Fe@SiO2.
| Fe NPs | Sample 4 | |||
|---|---|---|---|---|
| BE (eV) (FWHM (eV)) | At% | BE (eV) (FWHM (eV)) | At% | |
| C1s | 285.0 (1.3) | 52.1 | 285.0 (1.6) | 11.1 |
| 286.3 (1.7) | 10.4 | 286.3 (1.8) | 4.9 | |
| 288.7 (1.6) | 4.2 | 288.6 (1.6) | 1.6 | |
| Total at% | 66.7 | 17.6 | ||
| O1s | 529.6 (1.4) | 10.0 | 530.8 (1.9) | 5.3 |
| 531.5 (2.0) | 10.1 | 533.4 (2.3) | 53.4 | |
| 533.4 (1.9) | 3.1 | |||
| Total at% | 23.2 | 58.7 | ||
| Fe2p3/2(Fe(0) | 706.3 | 4.1 | 706.8 | 0.2 |
| Fe2p3/2 (Fe(ii/iii)) | 6.0 | 2.8 | ||
| Total at% | 10.1 | 3.0 | ||
| Si2p3/2–1/2 | — | — | 103.9–104.5 (2.1–2.1) | 20.0 |
| N1s | — | — | 0.7 | |