Catalytically Active Silicon Oxide Nanoclusters Stabilized in a Metal–Organic Framework

Post‐synthetic modification of the zirconium‐based metal–organic framework (MOF) NU‐1000 by atomic layer deposition (ALD), using tetramethoxysilane (Si(OMe) 4 ) as a precursor, led to the incorporation and stabilization of silicon oxide clusters composed of only a few silicon atoms in the framework's pores. The resulting SiO x functionalized material (Si‐NU‐1000) was found to be catalytically active despite the inactivity of related bulk silicon dioxide (SiO 2 ), thus demonstrating the positive effects of having nanosized clusters of SiO x . Moreover, Si‐NU‐1000 showed activity greater than that found for aluminum oxide based catalysts—oxides known for their high acidity—such as an aluminum oxide functionalized MOF (Al‐NU‐1000) and bulk γ‐Al 2 O 3 . X‐ray photoelectron spectroscopy and infrared spectroscopy measurements unmasked the electron donating nature of Si‐NU‐1000, explaining the unusual electronic properties of the nanosized SiO x clusters and supporting their high catalytic activity.