Structure–Property-Performance Relationship of Ultrathin Pd–Au Alloy Catalyst Layers for Low-Temperature Ethanol Oxidation in Alkaline Media

Pd-containing alloys are promising materials for catalysis. Yet, the relationship of the structure–property performance strongly depends on their chemical composition, which is currently not fully resolved. Herein, we present a physical vapor deposition methodology for developing PdxAu1–x alloys with fine control over the chemical composition. We establish direct correlations between the composition and these materials’ structural and electronic properties with its catalytic activity in an ethanol (EtOH) oxidation reaction. By combining X-ray diffraction (XRD) and X-ray photelectron spectroscopy (XPS) measurements, we validate that the Pd content within both bulk and surface compositions can be finely controlled in an ultrathin-film regime. Catalytic oxidation of EtOH on the PdxAu1–x electrodes presents the largest forward-sweeping current density for x = 0.73 at ∼135 mA cm–2, with the lowest onset potential and largest peak activity of 639 A gPd–1 observed for x = 0.58. Density functional theory (DFT) ca...