Synthesis and characterization of carbon supported PtW catalysts from carbonyl complexes for oxygen electroreduction

Carbon supported PtW alloy nanoparticles with well-controlled particle size, morphology, and dispersion have been synthesized by the thermal decomposition of carbonyl complexes at elevated temperatures. The synthesized alloy nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and electrochemically analyzed for activity towards molecular oxygen electroreduction in an acidic electrolyte. The influence of synthesis parameters on the size of PtW nanoparticles were also investigated. XRD results show that the structure of PtW nanoparticles is composition dependent with a predominate face centered cubic structure for tungsten content less than ∼65%. Phase segregation was observed for PtW alloys with higher tungsten content. The prepared PtW nanoparticles exhibit significantly higher platinum mass specific activity towards molecular oxygen electroreduction than commercially available Pt/C catalysts, hence, the amount of platinum used in fuel cell cathode could be reduced dramatically.