Preparation and characterization of successively deposited Pt/Ru bimetallic electrocatalysts for the methanol oxidation

Two types of Pt/Ru electrocatalysts, which have different structural characteristics, were prepared with different synthetic routes. That is, Pt/Ru electrocatalysts were synthesized by the coreduction and successive deposition methods, respectively. The structural and catalytic properties of Pt/Ru electrocatalysts were characterized by XRD, TEM, voltammetry and chronoamperometry. From the XRD analysis, coreduced and successively deposited Pt/Ru electrocatalysts had an alloyed structure. TEM analyses showed that all the electrocatalysts had a highly dispersed state on the Vulcan XC-72R substrate. From the voltammetry, the coreduced electrocatalysts displayed higher catalytic activity than the successively deposited electrocatalysts for the electrooxidation of methanol. These results explain why coreduced catalysts are better able to dehydrogenate methanol and have a greater CO tolerance than the successively deposited ones. But chronoamperometry showed that successively deposited Pt/Ru electrocatalysts had stability similar to that of the coreduced ones. Although the successively deposited electrocatalysts showed lower catalytic activity than the coreduced ones, their enhanced catalytic activity was obtained by the successive deposition method in the comparison of methanol oxidation current density with pure platinum electrocatalyst.