Micron‐sized membrane reactors: Multicompartment semipermeable polymer particles containing palladium nanoparticles

Abstract

Multicompartment polymer microparticles are prepared encapsulating palladium nanoparticles within closed-shell compartments, using a double-emulsion (W 1 /O/W 2 ), evaporative limited coalescence process. The encapsulation efficiency in some cases is as high as 99%, and very little Pd leaches from the particles. The Pd nanoparticles dispersed in an aqueous environment within the closed-shell compartments of the microparticles catalyze hydrogenation reactions of low molar mass substrates in water at substantial rates. The microparticle walls serve as semipermeable membranes, permitting diffusion of small molecules into the compartments while retaining the larger metal nanoparticles. The microparticles can be reused after simple filtration. The catalytic activity increases on recycling, possibly because of plasticization of polymer walls by the reactant and products, resulting in increased diffusion. In a second demonstration of catalytic activity, the microparticles efficiently decompose hydrogen peroxide. These nanoparticle-containing microparticles serve as convenient, reusable catalyst carriers, and prevent inadvertent human and environmental contact with nanoparticles.