title: Oxidation of nanoscale Au-In alloy particles as a possible route toward stable Au-based catalysts.
abstract: The oxidation of bimetallic alloy nanoparticles comprising a noble and a nonnoble metal is expected to cause the formation of a single-component surface oxide of the nonnoble metal, surrounding a core enriched with the noble metal. Studying the room temperature oxidation of Au-In nanoparticles, we show that this simple picture does not apply to an important class of bimetallic alloys, in which the oxidation proceeds via predominant oxygen diffusion. Instead of a crystalline In2O3 shell, such oxidation leads to an amorphous shell of mixed Au-In oxide that remains stable to high temperatures and whose surface layer is enriched with Au. The Au-rich mixed oxide is capable of adsorbing both CO and O2 and converting them to CO2, which desorbs near room temperature. The oxidation of Au-In alloys to a mixed Au-In oxide shows significant promise as a viable approach toward Au-based oxidation catalysts, which do not require any complex synthesis processes and resist deactivation up to at least 300 °C.
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA. esutter@bnl.gov
authors.forename: Eli A
authors.initials: EA
authors.lastname: Sutter
authors.forename: Xiao
authors.initials: X
authors.lastname: Tong
authors.forename: Katherine
authors.initials: K
authors.lastname: Jungjohann
authors.forename: Peter W
authors.initials: PW
authors.lastname: Sutter
keywords: X-ray photoelectron spectroscopy; temperature programmed desorption; transmission electron microscopy