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138 Chapter 5<br />
obtained Pd-doped solid (Figure 5.14), indicating the absence of nitrate from the<br />
employed for the synthesis of Cu/Pd-BTC_4 Cu-salt. The absence of Cl - in the Cu/Pd-<br />
BTC_4 sample is hard to rule out based only on the IR and 1 H-NMR data. Further<br />
characterizations, namely SEM-EDX and XPS, will addresses this issue.<br />
Figure 5.15. SEM images of the Cu/Pd-BTC samples.<br />
Figure 5.16. EDX elemental mapping of the Cu/Pd-btc_4. Red: Cu-mapping; green: Pd-mapping.<br />
Curiously, SEM image of the sample Cu/Pd-BTC_4 displays that its particles have welldefined<br />
octahedral shape and are visibly bigger (ca. 20 μm) compared to the other solid<br />
(Cu/Pd-BTC_3) (Figure 5.15). Thus, variation of the Pd-precursor apparently influences<br />
extent of palladium inclusion and morphology of the Cu/Pd-MOF particles (as also<br />
reflected in the PXRD, Figures 5.13): Pd(II) acetate favors quantitative palladium<br />
incorporation (samples Cu/Pd-BTC_1-3), while PdCl2 somehow decelerates MOF growth,<br />
leading therefore to larger crystals (sample Cu/Pd-BTC_4). SEM-EDX mapping of the<br />
Cu/Pd-BTC_4 solid shows the homogeneous distribution of Pd and Cu in the particles of<br />
framework (Figure 5.16). In addition, the formation of some Pd species where there is no<br />
contribution of Cu has also been observed. These Pd species could be assigned to Pd-Pd<br />
PWs or just Pd NPs. Due to the beam stability of Cu/Pd-BTC under high electron voltage,
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