Zeolitic Pickering Emulsifier with Intrinsic Amphiphilicity.

The formation of oil-in-water Pickering emulsions stabilized by lamellar zeolite (International Zeolite Association, three-letters code) emulsifier without surface grafting is investigated. The crucial emulsification factors are the oligolayer morphology and amphiphilicity developed upon acidic treatment (NH exchange/calcination, HNO treatment). In contrast with the readily available/abundant hydrophilic ≡Si-OH group in layer , the lipophilicity generated by strong acid sites is another key to the success of emulsification. Hydrocarbon-strong acid site interaction is long known in petrochemistry and superacid research. However, to the best of our knowledge, this interaction was first introduced to gain lipophilicity in emulsion formation. Finally, the Pd-loaded acidic form of the zeolite successfully stabilized the toluene/HO emulsion system. The biphasic interfacial nitroarene hydrogenation demonstrated excellent catalytic performance. Overall, this work provided not only a new kind of intrinsic solid to emulsify the organic-aqueous biphase system but also a new mechanism to generate lipophilicity. Both are important for the applications and designs of Pickering emulsion materials.