title: Tuning the activity of Pt(111) for oxygen electroreduction by subsurface alloying.
abstract: To enable the development of low temperature fuel cells, significant improvements are required to the efficiency of the Pt electrocatalysts at the cathode, where oxygen reduction takes place. Herein, we study the effect of subsurface solute metals on the reactivity of Pt, using a Cu/Pt(111) near-surface alloy. Our investigations incorporate electrochemical measurements, ultrahigh vacuum experiments, and density functional theory. Changes to the OH binding energy, ΔE(OH), were monitored in situ and adjusted continuously through the subsurface Cu coverage. The incorporation of submonolayer quantities of Cu into Pt(111) resulted in an 8-fold improvement in oxygen reduction activity. The most optimal catalyst for oxygen reduction has an ΔE(OH) ≈ 0.1 eV weaker than that of pure Pt, validating earlier theoretical predictions.
authors.affiliation: Center for Individual Nanoparticle Functionality, Department of Physics, Building 312, Technical University of Denmark, DK-2800 Lyngby, Denmark.
authors.forename: Ifan E L
authors.initials: IE
authors.lastname: Stephens
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Bondarenko
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Perez-Alonso
authors.forename: Federico
authors.initials: F
authors.lastname: Calle-Vallejo
authors.forename: Lone
authors.initials: L
authors.lastname: Bech
authors.forename: Tobias P
authors.initials: TP
authors.lastname: Johansson
authors.forename: Anders K
authors.initials: AK
authors.lastname: Jepsen
authors.forename: Rasmus
authors.initials: R
authors.lastname: Frydendal
authors.forename: Brian P
authors.initials: BP
authors.lastname: Knudsen
authors.forename: Jan
authors.initials: J
authors.lastname: Rossmeisl
authors.forename: Ib
authors.initials: I
authors.lastname: Chorkendorff
mesh_terms: D000497:Alloys / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D004563:Electrochemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000497:Alloys; D010984:Platinum; D003300:Copper; D010100:Oxygen