AuCu intermetallic nanoparticles: surfactant-free synthesis and novel electrochemistry

In the present work, a one-pot method is employed to synthesize AuCu intermetallic nanoparticles (AuCu iNPs) supported on high-surface-area carbon. To avoid blocking the active sites of the AuCu iNPs for the subsequent study of electrocatalysis, no surfactant has been applied in the entire synthetic process. After refluxing in glycerol at 300 degrees C, the ordered structure is formed in the carbon-supported AuCu iNPs, whose superlattice is evidently demonstrated by the X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterizations. Such intermetallic nanoparticles show very interesting electrochemical behaviors which have hitherto not been reported in the literature. In addition to the peculiar cyclic voltammetry (CV), the AuCu iNPs exhibit a superior catalytic activity, in comparison to that of ordinary Au nanoparticles, toward the oxygen reduction reaction (ORR) in alkaline media. The alteration in the surface electronic properties of Au, caused by the incorporation of Cu, has also been studied by X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations.