Physical and electrochemical characterizations of PtPb/C catalyst prepared by pyrolysis of platinum(II) and lead(II) acetylacetonate

Platinum (Pt) and platinum-lead (PtPb) nanoparticles supported on Vulcan XC-72 carbon are prepared by polyalcohol reduction of platinum acetylacetonate and lead acetylacetonate in octyl ether. The catalysts are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Pt and PtPb nanoparticles, which are controlled by a capping agent added during the synthesis, have diameters of 2.5-6 nm. The Pt/C and PtPb/C catalysts display the characteristic diffraction peaks of a face-centered cubic Pt structure and the pure phase of the PtPb intermetallic, respectively. Results from XPS analysis reveal that the PtPb/C catalyst contains mostly Pt(0), Pb(0) and carbon, with traces of Pt(IV) (e.g., PtO₂) and -C{double bond, long}O. The electrocatalytic activity of the PtPb/C catalyst towards formic acid and methanol oxidation is investigated by cyclic voltammetry, impedance measurements and chronoamperometry. The PtPb/C catalyst has higher electrocatalytic activity for both formic acid and methanol oxidation than the Pt/C and commercially-available PtRu/C catalysts. Preliminary tests on a single cell indicate that a PtPb/C anode catalyst gives the best electrocatalytic performance among all Pt/C, PtPb/C and PtRu/C catalysts.