title: Probing the Active Surface Sites for CO Reduction on Oxide-Derived Copper Electrocatalysts.
abstract: CO electroreduction activity on oxide-derived Cu (OD-Cu) was found to correlate with metastable surface features that bind CO strongly. OD-Cu electrodes prepared by H2 reduction of Cu2O precursors reduce CO to acetate and ethanol with nearly 50% Faradaic efficiency at moderate overpotential. Temperature-programmed desorption of CO on OD-Cu revealed the presence of surface sites with strong CO binding that are distinct from the terraces and stepped sites found on polycrystalline Cu foil. After annealing at 350 °C, the surface-area corrected current density for CO reduction is 44-fold lower and the Faradaic efficiency is less than 5%. These changes are accompanied by a reduction in the proportion of strong CO binding sites. We propose that the active sites for CO reduction on OD-Cu surfaces are strong CO binding sites that are supported by grain boundaries. Uncovering these sites is a first step toward understanding the surface chemistry necessary for efficient CO electroreduction.
authors.affiliation: †Center for Individual Nanoparticle Functionality, Department of Physics, Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
authors.forename: Arnau
authors.initials: A
authors.lastname: Verdaguer-Casadevall
authors.affiliation: ‡Department of Chemistry, Stanford University, Stanford, California 94305, United States.
authors.forename: Christina W
authors.initials: CW
authors.lastname: Li
authors.affiliation: †Center for Individual Nanoparticle Functionality, Department of Physics, Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
authors.forename: Tobias P
authors.initials: TP
authors.lastname: Johansson
authors.affiliation: †Center for Individual Nanoparticle Functionality, Department of Physics, Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
authors.forename: Soren B
authors.initials: SB
authors.lastname: Scott
authors.affiliation: §Materials Science Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: McKeown
authors.affiliation: ∥Materials Engineering Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States.
authors.forename: Mukul
authors.initials: M
authors.lastname: Kumar
authors.affiliation: †Center for Individual Nanoparticle Functionality, Department of Physics, Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
authors.forename: Ifan E L
authors.initials: IE
authors.lastname: Stephens
authors.affiliation: ‡Department of Chemistry, Stanford University, Stanford, California 94305, United States.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Kanan
authors.affiliation: †Center for Individual Nanoparticle Functionality, Department of Physics, Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
authors.forename: Ib
authors.initials: I
authors.lastname: Chorkendorff