Cl-assisted highly efficient synthesis of FePd sub(3) alloys encapsulated in graphite papers: a two stage CVD approach

Recently it has been shown that FePd alloys can be encapsulated in graphitic carbon based systems for a better particle dispersion through addition of dichloro-cyclooctadiene palladium to ferrocene. Here we propose an advanced two-stage method which allows the synthesis of very thick deposits of planar rolled-like graphite structures filled with FePd sub(3) alloys as dominant product in the entire reactor. The first stage is used to pyrolyze the Pd-containing hydrocarbon on the top of Si/SiO sub(2) substrates for Pd deposition while the second stage is used for the evaporation and pyrolysis of the Fe-containing precursor (ferrocene) for the FePd alloy formation and encapsulation. Annealing studies also show that no changes in the unit cell of the FePd sub(3) structure are found even after tens of hours at 600-650 degree C under Ar/H sub(2) flow. Instead a change in the encapsulated particle shape and spatial arrangement is found. The samples are characterized in detail through scanning and transmission electron microscopy, energy dispersive X-rays, Raman spectroscopy, thermogravimetric analyses, X-ray diffraction and room-temperature magnetometry.