Metal nanoparticles (NPs) stabilized by metal−organic frameworks (MOFs) are very promising for catalysis, while reports on their cooperative catalysis for a cascade reaction have been very rare. In this work, Pd NPs incorporated into a MOF, MIL-101, have jointly completed a tandem reaction on the basis of MOF Lewis acidity and Pd NPs. Subsequently, ultrafine PdAg alloy NPs (∼1.5 nm) have been encapsulated into MIL-101. The obtained multifunctional PdAg@MIL-101 exhibits good catalytic activity and selectivity in cascade reactions under mild conditions, on the basis of the combination of host−guest cooperation and bimetallic synergy, where MIL-101 affords Lewis acidity and Pd offers hydrogenation activity while Ag greatly improves selectivity to the target product. As far as we know, this is the first work on bimetallic NP@MOFs as multifunctional catalysts with multiple active sites (MOF acidity and bimetallic species) that exert respective functions and cooperatively catalyze a one-pot cascade reaction.
The phase boundary between spinel (gamma phase) and MgSiO3 perovskite + MgO periclase in Mg2SiO4 was determined by in situ x-ray measurements by a combination of the synchrotron radiation source (SPring-8) and a large multianvil high-pressure apparatus. The boundary was determined at temperatures between 1400 degrees to 1800 degreesC, demonstrating that the postspinel phase boundary has a negative Clapeyron slope as estimated by quench experiments and thermodynamic analyses. The boundary was located at 21.1 (+/-0.2) gigapascals, at 1600 degreesC, which is approximately 2 gigapascals lower than earlier estimates based on other high-pressure studies.
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