Triflicacid-functionalizedsilica-coatedmagneticnanoparticles [γ-Fe2O3@SiO2-TfOH] were readily prepared and identified as an effictive catalyst for the transformation of aldehydes or ketones into their corresponding gem-dihydroperoxides with 30% aqueous hydrogen peroxide. The catalyst was easily separated by magnetic decantation and the recovered catalyst was reused for seven cycles without significant