Porous Fe3O4 nanoparticles: Synthesis and application in catalyzing epoxidation of styrene

► Porous Fe3O4 particles with pore size around 2 nm were synthesized via a simple route without structure-directing agent. ► The formation mechanism of the porous Fe3O4 particles was discussed. ► The obtained porous Fe3O4 particles were used to immobilize Au nanoparticles with the assistance of l-cysteine. ► The Au/l-Fe3O4 nanocomposite can effectively catalyze the epoxidation of styrene to styrene oxide with high performance.