Fe₃O₄/Porphyrin Covalent Organic Framework Core–Shell Nanospheres as Interfacial Catalysts for Enzymatic Esterification

A nanoscale core–shell-structured magnetic microsphere (abbreviated as Fe3O4@DhaTph-lipase), which consists of an Fe3O4 core, a porphyrin covalent organic framework DhaTph shell with loaded lipase, is reported. The obtained Fe3O4@DhaTph-lipase microsphere can be a powerful emulsifier to stabilize the water-in-n-hexane Pickering emulsion for at least one month without any demulsification under ambient conditions. Furthermore, Fe3O4@DhaTph-lipase with lipase enzyme and a large specific surface area is a droplet microreactor and displays excellent interfacial catalytic activity to promote enzymatic esterification reaction via visible light-induced photothermal conversion. On the other hand, the magnetically triggered Pickering emulsion interfacial catalyst can be recycled at least 10 times with robust performance. The potential utility of this strategy is highlighted by the fabrication of many more multifunctional covalent organic framework-based Pickering emulsion catalytic systems to promote various organic transformations in a green, smart, and facile way.