Electrocatalytic Methanol Oxidation of Pt0.5Ru0.5-xSnx/C (x = 0−0.5)

In this paper, we reported on the electrocatalytic activities for methanol oxidation of Pt 0.495 Ru 0.505 /C, Pt 0.526 Sn 0.474 /C, Pt 0.467 Ru 0.495 Sn 0.038 /C, Pt 0.472 Ru 0.413 Sn 0.115 /C, Pt 0.504 Ru 0.354 Sn 0.142 /C, Pt 0.537 Ru 0.243 Sn 0.22 /C, and Pt 0.487 Ru 0.152 Sn 0.361 /C catalysts. The carbon-supported alloy catalysts were prepared by a modified electroless deposition method. The electrocatalytic activities for methanol oxidation were investigated by using cyclic voltammetry, chronoamperometry, slow linear sweep measurements, and Tafel steady-state plots. The results indicate that the Pt 0.472 Ru 0.413 Sn 0.115 /C catalyst exhibits superior electrochemical performance for methanol oxidation. Tafel plots demonstrate that the addition of Sn into the binary Pt−Ru system could accelerate the rate-determining reactions (RDS) of methanol oxidation rather than alter the RDS step. The apparent activation energies for methanol oxidation of the binary and ternary catalysts were determined by Tafel plots at different temperatures, showing that Pt 0.472 Ru 0.413 Sn 0.115 /C can significantly lower the activation energy in comparison with that of Pt−Ru/C and Pt−Sn/C. The present results confirm the synergy effect of Ru and Sn in the electrocatalysts and meanwhile suggest the applicability of Pt 0.472 Ru 0.413 Sn 0.115 /C for methanol oxidation with reduced catalyst price and enhanced catalytic activity.