An analysis of the effect of zirconium precursors of MOF-808 on its thermal stability, and structural and surface properties

Abstract

Different zirconium precursors lead to different bulk properties but similar defective surfaces.

Enhancing the Catalytic Activity of MOF‐808 Towards Peptide Bond Hydrolysis through Synthetic Modulations

“…Unlike ‐B, ‐D and ‐E, 130‐20‐A (Zr(O i Pr) 4 ) does not show loss of coordinated water or volatile solvent below 100 °C, and instead shows a distinct loss of adsorbed DMF and formate at 260 °C. This influence of precursor on stability is in contrast with the previous observations investigating the effect of precursor (ZrOCl 2 , ZrCl 4 , ZrO(NO 3 ) 2 ) over a 24 h synthesis, in which the thermal stability was little affected by the precursor identity [41] …”

“…In their case, ZrOCl 2 • 8H 2 O and ZrO(NO 3 ) 2 • xH 2 O produced MOF-808 with lower crystallinity, more disorder in the pore structure and lower surface areas than ZrCl 4 , which was attributed to the influence of water present in the precursor on the nucleation kinetics. [41] On the other hand, given the impact of structure on the reactivity, these reports also indirectly evidence that not only defect engineering but also other commonly overlooked factors could be used to tune the reactivity of MOFs. However, no clear understanding of how these so-called 'minor changes' could affect the MOF reactivity is available yet.…”

“…[44] Small amounts of water have also been demonstrated to enhance MOF yields by increasing the nucleation kinetics through promotion of Zr oxo clusters formation. [41,45] Further, Zr(O i Pr) 4 has also been suggested to favour MOF formation as the alkoxide deprotonates the BTC ligand, and facilitates BTC-Zr interactions. [46] Thermogravimetric Analysis (TGA) showed that the zirconium precursors affected the thermal stability and connectivity of the materials (Figure S1).…”

“…This influence of precursor on stability is in contrast with the previous observations investigating the effect of precursor (ZrOCl 2 , ZrCl 4 , ZrO (NO 3 ) 2 ) over a 24 h synthesis, in which the thermal stability was little affected by the precursor identity. [41] Analysis of the MOF particles by scanning electron microscopy (SEM) (Figure S2 and Table 1) revealed that all samples were quite amorphous, and MOFs with the typical octahedral shape of MOF-808 were not observed. [47] Regarding particle size, little influence of the precursor nature was observed as all successful syntheses (130-20-A, -B, -D and -E) showed similar average particle sizes of 15-17 μm, though the range of particle sizes was significantly higher for 130-20-E, with a variation of � 7.3 μm, compared to � 1.9 μm and � 2.6 μm for -A and -D, respectivly.…”

Fluorinated MOF-808 with various modulators to fabricate high-performance hybrid membranes with enhanced hydrophobicity for organic-organic pervaporation

“…All diffraction peaks can be well-indexed, which means that the synthesised MOFs possess a highly crystalline structure. The peaks at 2θ = 8.32° and 8.69° were assigned to diffraction from the planes (311) and (222) of MOF-808, respectively [47]. The high crystallinity was confirmed by the presence of very sharp peaks.…”