Metal-Organic Frameworks as Catalyst Supports: Influence of Defects on Metal Nanoparticle Formation
M Rivera-Torrente, M Filez, R Hardian, E M Reynolds, B Seoane, M-V Coulet, J P Hofmann, R A Fischer, A L Goodwin, P L Llewellyn and B M Weckhuysen
Chemistry – A European Journal 24, 7498-7506 (2018)
Because of their high tunability and surface area, metal-organic frameworks (MOFs) show great promise as supports for metal nanoparticles. Depending on the synthesis route, MOFs can contain defects. Here, we showcase that highly crystalline MIL-100(Fe) and semi-amorphous Basolite® F300 with identical iron 1,3,5-benzenetricarboxylate composition exhibit very divergent properties when used as support for Pd nanoparticle deposition. While MIL-100(Fe) shows a regular MTN-zeotype crystal structure with two types of cages, Basolite® F300 lacks long-range order beyond 8 Å and has a single pore system. The medium-range configurational linker-node disorder in Basolite® F300 results in a reduced number of Lewis acid sites, yielding more hydrophobic surface properties compared to hydrophilic MIL-100(Fe). The hydrophilic/hydrophobic nature of MIL-100(Fe) and Basolite® F300 impacts the amount of Pd and particle size distribution of Pd nanoparticles deposited during colloidal synthesis and dry impregnation methods, respectively. It is suggested that polar (apolar) solvents/precursors attractively interact with hydrophilic (hydrophobic) MOF surfaces, reaching tools at hand to increase the level of control over e.g. the nanoparticle size distribution.