Structural effect of PtRu–WO3 alloy nanostructures on methanol electrooxidation

PtRu–WO3 alloy thin-film nanostructures for use as direct methanol fuel cells have been fabricated by co-sputtering for 20 and 40 at.% Ru. The structural and electrochemical properties of these nanostructures were characterized using transmission electron microscopy, X-ray diffraction, and electrochemical measurements. The nanostructures consist of PtRu alloy nanoparticles (4 nm in size) dispersed in the WO3 matrix. For 20 at.% Ru, the alloy nanoparticles are face-centered cubic (fcc), but for 40 at.% Ru, the nanoparticles separate into Pt-rich fcc and Ru-rich hexagonal-close packed (hcp) phases.