Encapsulating Copper Nanocrystals into Metal-Organic Frameworks for Cascade Reactions by Photothermal Catalysis

Composite materials with multifunctional properties usually possess synergetic effects in catalysis toward cascade reactions. In this work, a facile strategy to the encapsulation of octahedral Cu2O nanocrystals (NCs) by metal-organic frameworks (MOFs) is reported, and an oriented growth of MOF enclosures (namely, HKUST-1) around Cu2O NCs with desired feedstock ratio is achieved. The strategy defines the parameter range that precisely controls the etching rate of metal oxide and the MOF crystallization rate. Finally, the Cu@HKUST-1 composites with uniform morphology and controlled MOF thickness have been successfully fabricated after the reduction of Cu2O to Cu NCs in HKUST-1. The integration of Cu NCs properties with MOF advantages helps to create a multifunctional catalyst, which exhibits cooperative catalytic activity and improved recyclability toward the one-pot cascade reactions under mild conditions involving visible-light irradiation. The superior performance can be attributed to the plasmonic photothermal effect of Cu NCs, while HKUST-1 shell provides Lewis acid sites, substrates and H-2 enrichment, and stabilizes the Cu cores.

Automated summary

In this work, nanocrystals of Cu2O were encapsulated by metal-organic frameworks (MOFs) through a simple strategy, resulting in the successful fabrication of Cu@HKUST-1 composites with uniform morphology and controlled MOF thickness. The integration of Cu NCs properties with MOF advantages helped to create a multifunctional catalyst, exhibiting cooperative catalytic activity and improved recyclability.