Preparation of core-shell Pt@Fe3O4@SiO2 nanostructures by oxidation of core-shell FePt@SiO2 nanoflowers and their performance in preferential CO oxidation reaction

Core–shell Pt@Fe3O4@SiO2 nanostructures were successfully prepared in three step procedure. FePt nanoflowers were first prepared by an oleylamine-mediated chemical synthetic route, and then coated with thin silica (SiO2) layer (~5 nm) by a method based in microemulsion. Then, the core–shell Pt@Fe3O4@SiO2 nanostructures were prepared thorough the calcination step at 550 °C in air static of FePt nanoflowers (FePt@SiO2) samples. The silica layer played an important role to avoid nanoparticles agglomeration during the heat treatment. Iron oxide (Fe3O4) shell grown on Pt nanoparticle surface showed able to act as promoter for CO conversion in Preferential Reaction of Oxidation of CO (PROX-CO).