Simultaneous gas-phase loading of MOF-5 with two metal precursors: towards bimetallics@MOF

Simultaneous gas-phase loading of [Zn₄O(bdc)₃] (bdc = 1,4-benzenedicarboxylate; MOF-5) with combinations of two different MOCVD precursors such as [Fe(η⁶-toluene)(η⁴C ₄H₆)]/[CpPtMe₃], [CpPd(η³-C ₃H₅)]/[CpPtMe₃] and [Ru(cod)(cot)]/[Pt(cod)Me2] was followed by solid state ¹³C MAS NMR spectroscopy, elemental analysis and X-ray powder diffraction (PXRD). Different: amounts of precursors were applied for the loading experiments. It was found that defined molar ratios of the adsorbed precursors inside MOF-5 can be achieved when the loading is below the saturation level of MOF-5 for adsorption of the individual precursors. The cohydrogenolysis of the loaded material [Ru(cod)(cot)]/[Pt(cod)Me ₂]@MOF-5 was selected as a representative example to study the possibility of obtaining bimetallic PtRu nanoparticles hosted inside the MOF support. The quantitative cohydrogenolysis of the adsorbed metal precursors led to formation of alloyed metal nanoparticles as revealed by PXRD, transmission electron microscopy (TEM) and selected area electron diffraction. However, the bdc linkers of the MOF-5 host material were partially hydrogenated which caused a severe distortion of the MOF-5 matrix, loss of long range crystalline order and reduction of the BET surface area down to 380 m²q^-1.