Magnetite/poly(4-vinylpyridine) composite nanospheres with multiple Fe3O4 cores embedded in a P4VP shell were first synthesized by miniemulsion polymerization and then used as recoverable supports for MoO2(acac)(2) complex. The supported complex, together with superparamagnetism and strong magnetic response, showed high efficiency for the catalytic epoxidation of cis-cyclooctene with aqueous H2O2 in ethanol. The response strongly facilitated the easy recovery of the catalyst, which was stable in recycling tests. (c) 2013 Elsevier B.V. All rights reserved.