title: Surface Tension Effects on the Reactivity of Metal Nanoparticles.
abstract: We present calculated adsorption energies of oxygen on gold and platinum clusters with up to 923 atoms (3 nm diameter) using density functional theory. We find that surface tension of the clusters induces a compression, which weakens the bonding of adsorbates compared with the bonding on extended surfaces. The effect is largest for close-packed surfaces and almost nonexistent on the more reactive steps and edges. The effect is largest at low coverage and decreases, even changing sign, at higher coverages where the strain changes from compressive to tensile. Quantum size effects also influence adsorption energies but only below a critical size of 1.5 nm for platinum and 2.5 nm for gold. We develop a model to describe the strain-induced size effects on adsorption energies, which is able to describe the influence of surface structure, adsorbate, metal, and coverage.
authors.affiliation: SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University , 443 Via Ortega, Stanford, California 94305, United States.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.affiliation: SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States.
authors.forename: Frank
authors.initials: F
authors.lastname: Abild-Pedersen
authors.affiliation: School of Chemical Engineering, Purdue University , 480 Stadium Mall Drive, West Lafayette, Indianapolis 47907, United States.
authors.forename: Jeff
authors.initials: J
authors.lastname: Greeley
authors.affiliation: SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University , 443 Via Ortega, Stanford, California 94305, United States.|SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States.
authors.forename: Jens K
authors.initials: JK
authors.lastname: Nørskov
keywords: DFT; finite-size effects; heterogeneous catalysis