Pt and Pt-Rh nanowires supported on carbon and SnO2:Sb nanoparticles for ethanol electrochemical oxidation in acidic media

Pt and Pt-Rh nanowires were successfully synthesized by chemical reduction with formic acid without any surfactants and were applied for the study of ethanol electrochemical oxidation in acidic media. The synthesis process lasted 72 h at room temperature and the nanowires were obtained with 40 wt% metal loading with respect to the carbon support. In addition, mixtures of carbon- and antimony-doped tin oxide were prepared and used as support in order to improve the catalytic activity and stability of the catalysts. Electrochemical activity was studied by cyclic voltammetry, chronoamperometry, and derivative voltammetry and the stability was tested by electrolysis at 0.6 V for 22 h. Physical characterization was carried out by X-ray diffraction, field emission gun scanning electron microscopy, and transmission electron microscopy. All Pt-Rh nanowires show higher activity than the commercial Pt/C catalyst towards ethanol oxidation. This feature is due to the fact that rhodium facilitates the cleavage of the C-C bond of the alcohol, resulting in higher oxidation efficiency. Physical characterization confirms the formation of nanowires that are widely dispersed on the supports, demonstrating the feasibility of the developed methodology for synthesis of Pt-Rh nanowires.