Zhao W, Wang Z, Malonzo CD, Webber TE, Platero-Prats AE, Sotomayor F, Vermeulen NA, Wang TC, Hupp JT, Farha OK, Penn RL, Chapman KW, Thommes M, Stein A (2018)
Publication Type: Journal article, Original article
Subtype: other
Publication year: 2018
Publisher: American Chemical Society
Book Volume: 30
Pages Range: 1301-1315
Journal Issue: 4
DOI: 10.1021/acs.chemmater.7b04893
The process of nanocasting in metal-org. frameworks (MOFs) is a versatile approach to modify these porous materials by introducing supporting scaffolds. The nanocast scaffolds can stabilize metal-oxo clusters in MOFs at high temps. and modulate their chem. environments. Here we demonstrate a range of nanocasting approaches in the MOF NU-1000, which contains hexanuclear oxozirconium clusters (denoted as Zr6 clusters) that are suitable for modification with other metals. We developed methods for introducing SiO2, TiO2, polymeric, and carbon scaffolds into the NU-1000 structure. The responses of NU-1000 toward different scaffold precursors were studied, including the effects on morphol., precursor distribution, and porosity after nanocasting. Upon removal of org. linkers in the MOF by calcination/pyrolysis at 500 °C or above, the Zr6 clusters remained accessible and maintained their Lewis acidity in SiO2 nanocast samples, whereas addnl. treatment was necessary for Zr6 clusters to become accessible to pyridine probe mols. in carbon nanocast samples. Aggregation of Zr6 clusters was largely prevented with SiO2 or carbon scaffolds even after thermal treatment at 500 °C or above. In the case of titania nanocasting, NU-1000 crystals underwent a pseudomorphic transformation, in which Zr6 clusters reacted with titania to form small aggregates of a Zr/Ti mixed oxide with a local structure resembling that of ZrTi2O6. The ability to maintain high densities of discrete Lewis acidic Zr6 clusters on SiO2 or carbon supports at high temps. provides a starting point for designing new thermally stable catalysts. [on SciFinder(R)]
APA:
Zhao, W., Wang, Z., Malonzo, C.D., Webber, T.E., Platero-Prats, A.E., Sotomayor, F.,... Stein, A. (2018). Extending compositional range of nanocasting in the oxozirconium cluster-based metal-organic framework NU-1000- comparative structural analysis. Chemistry of Materials, 30(4), 1301-1315. https://doi.org/10.1021/acs.chemmater.7b04893
MLA:
Zhao, Wenyang, et al. "Extending compositional range of nanocasting in the oxozirconium cluster-based metal-organic framework NU-1000- comparative structural analysis." Chemistry of Materials 30.4 (2018): 1301-1315.
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