Structure and Electrocatalysis of Sputtered RuPt Thin-Film Electrodes

The structural and electrochemical properties of RuPt thin-film electrodes fabricated by radio frequency (rf) magnetron sputtering have been investigated. Grazing incidence X-ray diffraction data show a transition from a face-centered cubic (fcc) to hexagonal cubic-packed (hcp) structure as the Ru percentage increases. The transition occurs gradually between 32 and 58% Ru, which is significantly different from the bulk RuPt phase diagram. The catalytic activity of the thin-film electrodes for methanol oxidation shows a broad peak near 40-60% Ru, consistent with previous reports. The relationship between catalytic activity and film structure is discussed and contrasted with previous investigations.