Journal of Applied Electrochemistry, Vol.45, No.2, 139-150, 2015
Sn@Pt and Rh@Pt core-shell nanoparticles synthesis for glycerol oxidation
The development and optimization of electrocatalysts for application in fuel cell systems have been the focus of a variety of studies where core-shell structures have been considered as a promising alternative among the materials studied. We synthesized core-shell nanoparticles of Sn (x) @Pt (y) and Rh (x) @Pt (y) (Sn@Pt, Sn@Pt-2, Sn@Pt-3, Rh@Pt, Rh@Pt-2, and Rh@Pt-3) through a reduction methodology using sodium borohydride. These nanoparticles were electrochemically characterized by cyclic voltammetry and further analyzed by cyclic voltammetry studying their catalytic activity toward glycerol electro-oxidation; chronoamperometry and potentiostatic polarization experiments were also carried out. The physical characterization was carried out by X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The onset potential for glycerol oxidation was shifted in 130 and 120 mV on the Sn@Pt-3/C and Rh@Pt-3/C catalysts, respectively, compared to commercial Pt/C, while the stationary pseudo-current density, taken at 600 mV, increased 2-fold and 5-fold for these catalysts related to Pt/C, respectively. Thus, the catalysts synthesized by the developed methodology have enhanced catalytic activity toward the electro-oxidation of glycerol, representing an interesting alternative for fuel cell systems.