A thermo-responsive polymer-tethered and Pd NP loaded UiO-66 NMOF for biphasic CB dechlorination

Abstract

Herein, we report a poly(N-isopropylacrylamide) sulfide (PNIPAM-S-) brush-tethered and Pd nanoparticle (NP) loaded UiO-66 type NMOF, namely Pd@UiO-66-S-PNIPAM, based on a NMOF–polymer covalent composite approach. The obtained multifunctional composite material can be a highly efficient Pickering emulsifier to stabilize the toluene-in-water emulsion; furthermore, it promotes the biphasic chlorobenzene (CB) dechlorination at the toluene–water interface in excellent yields at room temperature. More importantly, the Pd@UiO-66-S-PNIPAM emulsifier is thermo-responsive and can trigger emulsification at room temperature (25 °C) and demulsification at an elevated temperature (45 °C) of the toluene droplets, which makes product–catalyst in situ separation and recycling feasible. This temperature switchable Pickering emulsion catalytic system can be reused at least five times without any loss of its catalytic activity.