Synthesis of PtSn/carbon nanocomposites using trans-PtCl(PEt3)2(SnCl3) as the source of metal

Five Pt-Sn/Vulcan carbon nanocomposites containing metal nanoclusters highly dispersed on a carbon powder support have been prepared using trans-PtCl(PEt3)(2)(SnCl3) as the source of metal. Thermal gravimetric analysis of the decomposition of this complex in air reveals a single-step loss of all nonmetallic elements centered at 243 degreesC. X-ray diffraction (XRD) analysis confirms formation of PtSn (niggliite) nanocrystals as the only crystalline phase present in the nanocomposite products, excluding trace contamination by Pt metal in one sample. Pt/Sn atomic ratios determined from on-particle high-resolution energy-dispersive spectroscopy (HR-EDS) measurements are consistent with the formation of PtSn nanocrystals and provide no evidence for the formation of phase-separated compositions. Metal nanoclusters are formed using single or multiple depositions of precursor with average sizes of 7-26 nm even at metal loadings as high as 40 wt %.