Ternary Pt[sbnd]Ru[sbnd]C co-sputtered electrocatalysts having reaction selectivity for anodes and cathodes in direct methanol fuel cells

Abstract

In the present study, the reaction selectivity of methanol oxidation and O2 reduction at PtRuC co-sputtering samples has been described. The samples were prepared using the polygonal barrel-sputtering method and tested by linear sweep voltammetry in 0.5 mol/L H2SO4 containing methanol and O2. When sputtering was performed at a constant Ar gas pressure of 3 Pa, methanol oxidation became highly selective for the samples prepared at AC powers of 30 and 50 W. This characteristic was likely induced by the existence of O2 reduction intermediates, which can enhance the oxidation of CO, a methanol oxidation intermediate. The samples displaying O2 reduction selectivity were obtained at Ar gas pressure ranging between 0.4 and 3 Pa (AC power: 100 W). The O2 reduction selectivity may be attributed to the deposition of the electron-rich metallic Ru, which exhibits poor methanol oxidation performance. Based on these results, PtRuC samples that show reaction selectivity in methanol oxidation and O2 reduction are independently prepared by the polygonal barrel-sputtering method.