Integration of Pd nanoparticles with engineered pore walls in MOFs for enhanced catalysis

Summary Creating free-access active sites and regulating their interaction with substrates are crucial for efficient catalysis, yet remain a grand challenge. Herein, naked Pd nanoparticles (NPs) have been encapsulated in a metal-organic framework (MOF), MIL-101-NH2, to afford Pd@MIL-101-NH2. The hydrophobic perfluoroalkyls were post-synthetically modified onto -NH2 group to yield Pd@MIL-101-Fx (x = 3, 5, 7, 11, 15), which engineer the MOF pore walls to regulate Pd surrounding microenvironment and interaction with substrates. As a result, both the dehydrogenation coupling of organosilane and hydrogenation of halogenated nitrobenzenes show that their activity and selectivity can be greatly promoted upon hydrophobic modification due to the favorable substrate enrichment and regulated interactions between Pd and the modified MOF hosts, far surpassing the traditional supported or surfactant-protected Pd NPs. We envision metal NPs@MOF composites would be an ideal platform integrating the inherent activity of well-accessible metal sites with engineered microenvironment via readily tunable MOFs.