Bimetallic single-source precursors [M(NH3)4][Co(C2O4)2(H2O)2]·2H2O (M = Pd, Pt) for the one run synthesis of CoPd and CoPt magnetic nanoalloys

All the steps of the proposed technique, from the synthesis of single-source precursors to the preparation of CoPd and CoPt nanoalloys, are described. The double complex salts (DCS) [M(NH3)4][Co(C2O4)2(H2O)2]·2H2O (M = Pd, Pt), which were synthesized by mixing solutions containing [M(NH3)4]2+ cations and [Co(C2O4)2(H2O)2]2− anions, have been used as precursors. The salts obtained were characterized by IR spectroscopy, thermal analysis, XRD and single crystal X-ray diffraction. The prepared compounds crystallize in the monoclinic (space group I2/m, M = Pd) and orthorhombic (space group I222, M = Pt) crystal systems. Thermal decomposition of the salts in helium or hydrogen atmosphere at 200–600 °C results in the formation of nanoalloys powders (random solid solution Co0.50Pd0.50 and chemically ordered CoPt). The size of the bimetallic particles varied from 5 to 20 nm. Order–disorder structural transformations in Co0.50Pt0.50 nanoalloys were studied. The magnetic properties of both chemically disordered Co0.50Pd0.50 and ordered CoPt clusters have also been measured.

Figure optionsDownload as PowerPoint slideHighlights
► Double complex salts as single-source precursors for Co0.5Pd0.5 and CoPt nanoalloys.
► Disordered Co0.5Pd0.5 and Co0.5Pt0.5 nanoalloys formation mechanism.
► Control of Co0.5Pt0.5 nanoalloys order parameter by thermal mode.
► Partially ordered nanoalloys X-ray pattern modeling.
► 2.5 mB for Co0.5Pd0.5 and 2.0 mB for Co0.5Pt0.5 nanoalloys particles (7–21 nm).