Templated Fabrication of Core–Shell Magnetic Mesoporous Carbon Microspheres in 3-Dimensional Ordered Macroporous Silicas

Abstract

A confined synthesis strategy is demonstrated for the fabrication of core–shell magnetic mesoporous carbon microspheres by solvent evaporation induced self-assembly of ethanolic solutions of precursors (containing resol as carbon source, Pluronic F127 as a structure directing agent) in the cavity of presynthesized 3-dimensional ordered macroporous silica materials with each macropore filled with a magnetite particle. The obtained magnetic mesoporous carbon (Fe3O4@FDU-15) microspheres possess uniform diameter of ∼460 nm, ultralarge mesopores of 13.8 nm, high surface area of ∼403 m2/g, and strong magnetization (20.7 emu/g). Sub-4 nm gold nanoparticles are loaded in the porous shell of the magnetic microspheres, resulting in a novel Fe3O4@FDU-15/Au nanocatalyst with an excellent performance in catalyzing the epoxidation of styrene with high conversion (72%) and selectivity (85%) toward styrene oxide in 12 h and a good magnetic field-assisted recyclability.