International Journal of Hydrogen Energy, Vol.44, No.7, 3594-3602, 2019
Ternary Pt-Ru-C co-sputtered electrocatalysts having reaction selectivity for anodes and cathodes in direct methanol fuel cells
In the present study, the reaction selectivity of methanol oxidation and O-2 reduction at Pt-Ru-C 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 O-2. 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 O-2 reduction intermediates, which can enhance the oxidation of CO, a methanol oxidation intermediate. The samples displaying O-2 reduction selectivity were obtained at Ar gas pressure ranging between 0.4 and 3 Pa (AC power: 100 W). The O-2 reduction selectivity may be attributed to the deposition of the electron-rich metallic Ru, which exhibits poor methanol oxidation performance. Based on these results, Pt-Ru-C samples that show reaction selectivity in methanol oxidation and O-2 reduction are independently prepared by the polygonal barrel-sputtering method. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.