Metal Nanocrystals Embedded in Single Nanocrystals of MOFs Give Unusual Selectivity as Heterogeneous Catalysts

Abstract

The growth of nanocrystalline metal-organic frameworks (nMOFs) around metal nanocrystals (NCs)is useful in controlling the chemistry and metric of metal NCs. In this Letter, we show rare examples of nMOFs grown in monocrystalline from around metal NCs. Specifically, Pt NCs were subjected to around metal NCs. Specifically, Pt NCs [Zr6O4(OH)(4)(fumarate)(6), MOF 801; Zr6O4(OH)(4)(BDC)(6)(BDC = 1,4-benzenedicarboxylate), UiO-66; Zr6O4(OH)(4)(BPDC)6(BPDC = 4,4'biphenyldicarboxylate), UiO-67] as a single crystal within which the Pt NCs are embedded. These constructs (Pt subset of nMOF)(nanocrystal) are found to be active in gas phase hydrogenative conversion of methylcyclopentane (MCR) and give unusual product selectivity. The Pt subset of nUiO-66 shows selectivity to C-6-cyclic hydrocarbons such as cyclohexane and benzene that takes palce with 100 degrees C lower temperature than the standard reaction (Pt-on-SiO2). We observe a pore size effect in the nMOF series where the small pore of Pt subset of mMOF-801 does not produce the same products, while the larger pore Pt subset of nUiO-67 catalyst provides the smae products but with different selectivity. The (Pt subset of nMOF)(nanocrystal) spent catalyst is found to maintain the original crystallinity, and be recyclable without any byproduct residues.