Adsorption-driven surface segregation of the less reactive alloy component.

Counterintuitive to expectations and all prior observations of adsorbate-induced surface segregation of the more reactive alloy component (the one forming the stronger bond with the adsorbate), we show that CO adsorption at elevated pressures and temperatures pulls the less reactive Cu to the surface of a CuPt near-surface alloy. The Cu surface segregation is driven by the formation of a stable self-organized CO/CuPt surface alloy structure and is rationalized in terms of the radically stronger Pt-CO bond when Cu is present in the first surface layer of Pt. The results, which are expected to apply to a range of coinage (Cu, Ag)/Pt-group bimetallic surface alloys, open up new possibilities in selective and dynamical engineering of alloy surfaces for catalysis.

[1]  Jens K. Nørskov,et al.  Monte Carlo simulations of adsorption-induced segregation , 2002 .

[2]  G. Kresse,et al.  Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set , 1996 .

[3]  M. Mavrikakis,et al.  Interaction of Carbon Dioxide with Cu Overlayers on Pt(111) , 2008 .

[4]  Thomas Bligaard,et al.  Identification of Non-Precious Metal Alloy Catalysts for Selective Hydrogenation of Acetylene , 2008, Science.

[5]  Ib Chorkendorff,et al.  Methanol Synthesis from CO2, CO, and H2over Cu(100) and Ni/Cu(100) , 1999 .

[6]  Jingguang G. Chen,et al.  Experimental and theoretical investigation of the stability of Pt-3d-Pt(111) bimetallic surfaces under oxygen environment. , 2006, The journal of physical chemistry. B.

[7]  J. Nørskov,et al.  Improved adsorption energetics within density-functional theory using revised Perdew-Burke-Ernzerhof functionals , 1999 .

[8]  Cheol-Woo Yi,et al.  The Promotional Effect of Gold in Catalysis by Palladium-Gold , 2005, Science.

[9]  J. Nørskov,et al.  Computational high-throughput screening of electrocatalytic materials for hydrogen evolution , 2006, Nature materials.

[10]  I. Chorkendorff,et al.  Methanol synthesis from CO2, CO and H2 over Cu(1 0 0) and Cu(1 0 0) modified by Ni and Co , 2000 .

[11]  I. Chorkendorff,et al.  Concepts of Modern Catalysis and Kinetics: CHORKEND:CONCEP.CATALYSIS O-BK , 2005 .

[12]  R. Behm,et al.  Interaction of CO with PdCu surface alloys supported on Ru(0 0 0 1) , 2004 .

[13]  Christian Mosch,et al.  CO adsorption on Cu-Pd alloy surfaces: ligand versus ensemble effects. , 2007, Physical chemistry chemical physics : PCCP.

[14]  Manos Mavrikakis,et al.  Trends in low-temperature water–gas shift reactivity on transition metals , 2005 .

[15]  G. D. Smith,et al.  Automobile exhaust catalysis at the atomic scale: atom‐probe investigations on platinum alloys , 2007 .

[16]  J. Nørskov,et al.  CO Desorption Rate Dependence on CO Partial Pressure over Platinum Fuel Cell Catalysts , 2004 .

[17]  I. Chorkendorff,et al.  Formate stability and carbonate hydrogenation on strained Cu overlayers on Pt(111) , 2008 .

[18]  B S Clausen,et al.  Catalyst design by interpolation in the periodic table: bimetallic ammonia synthesis catalysts. , 2001, Journal of the American Chemical Society.

[19]  M. Mavrikakis,et al.  A Cu/Pt near-surface alloy for water-gas shift catalysis. , 2007, Journal of the American Chemical Society.

[20]  Clausen,et al.  Design of a surface alloy catalyst for steam reforming , 1998, Science.

[21]  I. Chorkendorff,et al.  Investigation of the role of oxygen induced segregation of Cu during Cu 2 O formation on Cu{1 0 0}, Ag/Cu{1 0 0} and Cu(Ag) alloy , 2005 .

[22]  Feng Tao,et al.  Reaction-Driven Restructuring of Rh-Pd and Pt-Pd Core-Shell Nanoparticles , 2008, Science.

[23]  F. Illas,et al.  CO adsorption on monometallic Pd, Rh, Cu and bimetallic PdCu and RhCu monolayers supported on Ru(0001) , 2005 .

[24]  D. King,et al.  When adding an unreactive metal enhances catalytic activity: NOx decomposition over silver–rhodium bimetallic surfaces , 2007 .

[25]  S. Kaliaguine,et al.  Surface segregation of PdAg membranes upon hydrogen permeation , 1993 .

[26]  Konstantin M. Neyman,et al.  On the Promoting Role of Ag in Selective Hydrogenation Reactions over Pd−Ag Bimetallic Catalysts: A Theoretical Study , 2007 .