Ag nanoparticles encapsulated in carboxyl-functionalized hollow microporous organic nanospheres for highly efficient catalysis applications

In this work, we present a novel synthesis of Ag nanoparticles encapsulated in carboxyl-functionalized hollow microporous organic nanospheres (Ag@COOH-HMONs) by a combination of hyper-cross-linking mediated self-assembly and simply impregnation method, in which the COOH-HMONs supports were prepared via a Friedel-Crafts alkylation reaction by using polylactide-b-poly(tertbutyl acrylate)-b-polystyrene (PLA-b-PtBA-b-PS) triblock copolymer as precursors. Owing to the abundant carboxyl groups in the cavity of COOH-HMONs, highly dispersed silver nanoparticles can be successfully anchored into COOH-HMONs to produce Ag@COOH-HMONs via an ion exchange with AgNO3 following by an in-situ reduction of sodium borohydride (NaBH4). The obtained Ag@COOH-HMONs exhibit the high catalytic activities for the reduction of MB and nitroaromatic compounds as well as selective oxidation of thiol and styrene due to their high surface area, hierarchical porosity and yolk-shell nanostructure. This approach of constructing novel metal@porous organic polymers is expected to open doors for new types of yolk-shell structural catalysts for practical applications.