Silica-Protection-Assisted Encapsulation of Cu2 O Nanocubes into a Metal-Organic Framework (ZIF-8) To Provide a Composite Catalyst.

The integration of metal/metal oxide nanoparticles (NPs) into metal-organic frameworks (MOFs) to form composite materials has attracted great interest due to the broad range of applications. However, to date, it has not been possible to encapsulate metastable NPs with high catalytic activity into MOFs, due to their instability during the preparation process. For the first time, we have successfully developed a template protection-sacrifice (TPS) method to encapsulate metastable NPs such as Cu2 O into MOFs. SiO2 was used as both a protective shell for Cu2 O nanocubes and a sacrificial template for forming a yolk-shell structure. The obtained Cu2 O@ZIF-8 composite exhibits excellent cycle stability in the catalytic hydrogenation of 4-nitrophenol with high activity. This is the first report of a Cu2 O@MOF-type composite material. The TPS method provides an efficient strategy for encapsulating unstable active metal/metal oxide NPs into MOFs or maybe other porous materials.