Table 1.
Main physicochemical characteristics of Ce-Ln and Cu/Ce-Ln materials (Ln: Gd, La, Pr, Nd, Sm) obtained by BET, XRD and TPR analyses. Onset temperature of H2-TPR peaks is shown in bold, peak maxima in plain text and peak shoulders in italic.
| Samples | BET Analysis | XRD Analysis | TPR Analysis | |||
|---|---|---|---|---|---|---|
| SBET (m2/g) | Total Pore Volume (cm3/g) | Phase Detected (%v/v) b | Crystallite Size (nm) | Lattice Parameter (Å) c | Peak Temperatures (°C) a | |
| CeO2 | 72 | 0.27 | CeO2 cerianite | 15.9 ± 0.5 | 5.41 | 164, 507, 780 |
| Cu/CeO2 | 45 | 0.15 | CeO2 cerianite (55.2%) | 13.2 ± 0.2 | 5.41 | 139, 180, 220, 232, 836 |
| CuO tenorite (44.8%) | 70 ± 1 | |||||
| Ce-Gd | 5 | 0.09 | CeO2 cerianite (81.7%) | 16 ± 1 | 5.43 | 420, 654 |
| Gd1-xCexOy cubic (18.3%) | 31 ± 5 | 5.62 | ||||
| Cu/Ce-Gd | 3 | 0.05 | CeO2 cerianite (48.8%) | 25 ± 2 | 5.42 | 233, 293, 310, 402 |
| Gd1-xCexOy cubic (21.9%) | 51 ± 5 | 5.47 | ||||
| CuO tenorite (29.3%) | 10 ± 1 | |||||
| Ce-La | 25 | 0.14 | CeO2 cerianite (35.2%) | 18 ± 1 | 5.43 | 424, 551, 644 |
| La1-xCexOy (64.8%) | 34 ± 1 | 5.56 | ||||
| Cu/Ce-La | 23 | 0.08 | La1-xCexOy (66.2%) | 23 ± 2 | 5.51 | 281, 326, 343, 364 |
| La2CuO4 cubic (8.6%) | 49 ± 7 | 5.36 | ||||
| CuO tenorite (25.2%) | 11 ± 2 | |||||
| Ce-Pr | 22 | 0.15 | Pr1-xCexOy | 13 ± 1 | 5.43 | 312, 457, 484, 566 |
| Cu/Ce-Pr | 13 | 0.08 | CeO2 cerianite (87.8%) | 19 ± 1 | 5.41 | 207, 308, 328, 347 |
| CuO tenorite (12.2%) | 48 ± 5 | |||||
| Ce-Nd | 35 | 0.18 | Nd1-x CexOy * | 9 ± 1 | 5.49 | 390, 551, 810 |
| Cu/Ce-Nd | 33 | 0.08 | Nd1-x CexOy (62.7%) | 11 ± 1 | 5.47 | 280, 325, 358, 370 |
| Nd4Cu2O7 (7.9%) | 52 ± 5 | |||||
| CuO tenorite (29.4%) | 11 ± 1 | |||||
| Ce-Sm | 21 | 0.17 | CeO2 cerianite (77.8%) | 18 ± 1 | 5.44 | 429, 598 |
| Sm1-xCexOy (22.2%) | 20 ± 5 | 5.64 | ||||
| Cu/Ce-Sm | 19 | 0.08 | CeO2 cerianite (53.3%) | 15 ± 1 | 5.45 | 255, 295, 326, 348 |
| Sm2CuO4 tetragonal (9.2%) | 39 ± 5 | |||||
| Sm1-xCexOy cubic x ≈ 0.5 (7.5%) | 5 ± 1 | 5.65 | ||||
| CuO tenorite (30.0%) | 12 ± 1 | |||||
a The error for TPR experiments is ±5 °C; b Obtained by Rietveld analysis; c Calculated only for cubic structures.; * The Rietveld analysis also converges to a solution with 47.5% (v/v) of CeO2 (a = 5.45 Å) and 52.5% (v/v) of Nd1-xCexOy (a = 5.54 Å).