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

The growth of nanocrystalline metal–organic frameworks (nMOFs)around metal nanocrystals (NCs) is useful in controlling the chemistryand metric of metal NCs. In this Letter, we show rare examples ofnMOFs grown in monocrystalline form around metal NCs. Specifically,Pt NCs were subjected to reactions yielding Zr(IV) nMOFs [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 singlecrystal within which the Pt NCs are embedded. These constructs (Pt⊂nMOF)nanocrystalare found to be active in gas-phase hydrogenativeconversion of methylcyclopentane (MCP) and give unusual product selectivity.The Pt⊂nUiO-66 shows selectivity to C6-cyclic hydrocarbonssuch as cyclohexane and benzene that takes place with 100 °Clower temperature than the standard reaction (Pt-on-SiO2). We observe a pore size effect in the nMOF series wherethe small pore of Pt⊂nMOF-801 does not produce the same products,while the larger pore Pt⊂nUiO-67 catalyst provides the sameproducts but with different selectivity. The (Pt⊂nMOF)nanocrystalspent catalyst is found to maintain the originalcrystallinity, and be recyclable without any byproduct residues. [ABSTRACT FROM AUTHOR]