Bimetallic Co-Pt nanoparticles were synthesized at two distinct sizes (4 and 10 nm) by employing colloidal chemistry. As-synthesized nanoparticles were characterized by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) at the single particle level, indicating random arrangement of Co and Pt atoms throughout particles for both particle sizes. In-situ near edge X-ray absorption fine structure (NEXAFS) spectroscopy and ambient pressure X-ray photoelectron spectroscopy (APXPS) measurement were carried out over 4 nm Co-Pt alloy nanoparticles, while environmental TEM was employed to study larger 10 nm particles under H2-reducing atmospheres and catalytically-relevant CO2/H2 Fischer-Tropsch synthesis conditions. The results indicate the surface segregation of Pt and enrichment with Co of the subsurface regions under reducing environments. In accord with these findings, Co-Pt alloy nanoparticles exhibit Pt-like behavior during the CO2/H2 reaction under 5.5 bar, with 2:1 excess of H2 and at 250 degree Celsius.

In situ characterization of bimetallic Co-Pt nanoparticle catalysts for Fischer-Tropsch synthesis

244th National Meeting (2012)

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