Table 3 Coordination numbers obtained from fitting the EXAFS spectra
From: Stable complete methane oxidation over palladium based zeolite catalysts
Experiment | CNPd-Oa | CNPd-Pd | CNPd(-O-)Pdb | Fract. CNPd-Pdc | Fract. CNPd(-O-)Pdc |
|---|---|---|---|---|---|
Ex situ, 20 °C | |||||
PdO | 4 | – | 12 | – | 12 |
Pd foil | – | 12 | 12 | – | |
Pd/H-MOR | 4 | – | – | – | – |
Pd/Na-MOR | 4 | – | 6 | – | 6 |
Pd/H-MOR-BE | 4 | – | 3.3 | – | 3.3 |
Aging at 400 °C (Fig. 3) Pd/H-MOR | |||||
0 min | 2.9 | 0.5 | 1.0 | 1.8 | 1.4 |
15 min | 2.9 | 1.6 | 2.7 | 5.8 | 3.7 |
30 min | 2.9 | 1.9 | 4.2 | 6.9 | 5.8 |
90 min | 3 | 2.8 | 7.0 | 11.2 | 9.3 |
Pd/Na-MOR | |||||
0 min | 3.9 | – | 6.0 | – | 6.2 |
90 min | 3.9 | – | 6.6 | – | 6.8 |
Redox at 350 °C (Fig. 4) Pd/H-MOR | |||||
1 s | 2.4 | 4.6 | 5.2 | 11.5 | 8.7 |
90 s | – | 11.3 | – | 11.3 | – |
210 s | – | 11.3 | – | 11.3 | – |
280 s | 1.4 | 7.0 | 3.9 | 10.8 | 11.1 |
550 s | 2.3 | 4.9 | 6.3 | 11.5 | 11.0 |
Pd/Na-MOR | |||||
1 s | 3.9 | – | 6.7 | – | 6.9 |
90 s | – | 10.2 | – | 10.2 | – |
210 s | – | 10.4 | – | 10.4 | – |
280 s | 2.4 | 3.6 | 2.3 | 9.0 | 3.8 |
550 s | 3.6 | 1.2 | 6.9 | 12.0 | 7.7 |
