An Efficient Bifunctional Core‐Shell ZIF‐90@ZIF‐67 Composite as a Stable Pickering Interfacial Catalyst for the Deacetalization–Knoevenagel Tandem Reaction

Exploiting advanced solid particles is crucial to the construction of Pickering emulsions catalysis. Recently, metal‐organic frameworks (MOFs) have been used as ideal emulsifiers stabilizing Pickering emulsions for interfacial catalysis. Although Pickering emulsions stabilized by core‐shell MOFs have significant importance in practical studies, to date there have been very limited reports on this topic. Herein, ZIF‐90@ZIF‐67, a core‐shell material with simultaneous acid‐base bifunctionality, was synthesized by seeded epitaxial growth. It was firstly applied as an emulsifier in Pickering emulsions to catalyze the deacetalization‐Knoevenagel tandem reaction, which exhibited excellent catalytic properties and achieved extremely high yields. Additionally, ZIF‐90@ZIF‐67 showed high stability and remained well repeatable after five cycles. This work provides a platform for the design of structurally and functionally diverse MOF‐based Pickering emulsions interfacial catalysis. Here, the core‐shell structure of ZIF‐90@ZIF‐67 was applied for the first time to catalyze the tandem reaction in Pickering emulsion system, which exhibited excellent catalytic performance with 99.9 % yield. Furthermore, ZIF‐90@ZIF‐67 has high stability and maintains good reproducibility after five cycles. This work provides a platform for the design of structurally and functionally diverse MOF‐based interfacial catalysis for Pickering emulsions.