Table 3. Surface Oxidation States and Speciation of CrMnOx Catalysts.
| surface
concentration (atm. %) |
||||||||
|---|---|---|---|---|---|---|---|---|
| Mn 2p3/2 |
Cr 2p3/2 |
O 1s |
||||||
| catalyst | Mn(II) | Mn(III) | Mn(IV) | Cr(III) | Cr(VI)a | Oβ | Oα | Oγ |
| 300-1 | 20.7 | 70.8 | 8.6 | 90.9 | 9.1 | 51.0 | 41.3 | 7.7 |
| 300-5 | 19.8 | 67.3 | 12.9 | 89.8 | 10.2 | 52.1 | 39.1 | 8.8 |
| 300-10 | 17.7 | 67.9 | 14.5 | 87.5 | 12.5 | 55.2 | 37.6 | 7.2 |
| 400-1 | 22.8 | 64.6 | 12.6 | 90.0 | 10.0 | 55.9 | 35.8 | 8.3 |
| 400-10 | 23.3 | 65.8 | 10.9 | 91.5 | 8.5 | 55.9 | 35.2 | 8.9 |
a
Concentration is uncertain due to possible in situ reduction in the measurement chamber.41