title: A Cu/Pt near-surface alloy for water-gas shift catalysis.
abstract: The primary route to hydrogen production from fossil fuels involves the water-gas shift (WGS) reaction, and an improvement in the efficiency of WGS catalysts could therefore lead to a major leap forward in the realization of hydrogen economy. On the basis of a combination of high-resolution scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory (DFT) calculations, we suggest the existence of a new thermodynamically stable Cu/Pt near-surface alloy (NSA). Temperature-programmed desorption and DFT reveal that this Cu/Pt NSA binds CO significantly more weakly than does Pt alone, thereby implying a considerable reduction in the potential for CO poisoning of the Cu/Pt NSA surface as compared to that of pure Pt. In addition, DFT calculations show that this Cu/Pt NSA is able to activate H2O easily, which is the rate-determining step for the WGS on several metal surfaces, and, at the same time, to bind the products of that reaction and formate intermediates rather weakly, thus avoiding possible poisoning of the catalyst surface. The Cu/Pt NSA is thus a promising candidate for an improved WGS catalyst.
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark.
authors.forename: Jan
authors.initials: J
authors.lastname: Knudsen
authors.forename: Anand U
authors.initials: AU
authors.lastname: Nilekar
authors.forename: Ronnie T
authors.initials: RT
authors.lastname: Vang
authors.forename: Joachim
authors.initials: J
authors.lastname: Schnadt
authors.forename: Edward L
authors.initials: EL
authors.lastname: Kunkes
authors.forename: James A
authors.initials: JA
authors.lastname: Dumesic
authors.forename: Manos
authors.initials: M
authors.lastname: Mavrikakis
authors.forename: Flemming
authors.initials: F
authors.lastname: Besenbacher
mesh_terms: D000497:Alloys / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D005740:Gases / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D008958:Models, Molecular; D008968:Molecular Conformation; D010984:Platinum / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D000497:Alloys; D005740:Gases; D014867:Water; D010984:Platinum; D003300:Copper