Amorphous Ni59Nb40Pt(1−x)Yx (Y = Sn, Ru; x = 0%, 0.4%) modified carbon paste electrodes and their role in the electrochemical methanol deprotonation and CO oxidation process

This work presents the electrochemical response to methanol deprotonation and CO oxidation in acid media (HClO4) of different compositional amorphous alloys obtained by ball milling technique. These powders with compositions Ni59Nb40Pt(1−x)Yx (x = 0%, 0.4% atm, Y = Sn, Ru ) are used as modified carbon paste electrodes (MCPEs), and mainly as anodes. Concerning the reactivity towards methanol electro-oxidation, the current density is drastically decreased with the presence of tin, susceptible to the potential range, followed by the Ni59Nb40Pt1 and Ni59Nb40Pt0.6Ru0.4 alloys, however DEMS studies demonstrates that the electrodes of compositions Ni59Nb40Pt 0.6Ru0.4 and Ni59Nb40Pt0.6Ru0.2Sn0.2 show the best tolerance to CO produced by methanol deprotonation, giving rise to more negative onset potential values for the CO2 production, although the voltammograms for the stripping of a CO monolayer clearly show that, the electrode that possesses a better tolerance to CO adsorbed on the surface of the electrode is Ni59Nb40Pt0.6Sn0.4, decreasing the onset potential values 281 mV and 158 mV with respect to the Ni59Nb40Pt1 and Ni59Nb40Pt0.6Ru0.4, respectively. The catalytic activity of the former electrode might be attributed to an adsorbed state of CO unique in this alloy.