Pickering Interfacial Catalysts with CO₂ and Magnetic Dual Response for Fast Recovering in Biphasic Reaction

Abstract

Pickering interfacial catalysis provides an excellent platform for biphasic reactions, but the separation and recycling of nanocatalysts is a challenge because of high adsorption energy of nanocatalysts at the liquid-liquid interface. In this work, we represent a new type of versatile Pickering emulsion based on magnetic and CO₂-responsive nanohybrids Fe₃O₄@SiO₂@P(TMA-DEA). The smart nanoparticles can stabilize the water-in-oil Pickering emulsion in the biphasic system and achieve the subsequent demulsification by bubbling CO₂ ascribed to their reversible switching surface. In the absence of energy barrier, the nanohybrids can be easily captured in situ by magnetic field in 2 min and showed excellent recyclability. In the Anelli system for alcohol oxidation, the nanocatalyst exhibited threefold enhancement in catalytic efficiency in comparison with an unemulsified two-phase and little loss on activity after five cycles. The conceptually novel dual-responsive system offers a green and energy-saving strategy for effective recycling of the nanocatalyst and intensification of biphasic reaction.