title: Quantitative and Atomic-Scale View of CO-Induced Pt Nanoparticle Surface Reconstruction at Saturation Coverage via DFT Calculations Coupled with in Situ TEM and IR.
abstract: Atomic-scale insights into how supported metal nanoparticles catalyze chemical reactions are critical for the optimization of chemical conversion processes. It is well-known that different geometric configurations of surface atoms on supported metal nanoparticles have different catalytic reactivity and that the adsorption of reactive species can cause reconstruction of metal surfaces. Thus, characterizing metallic surface structures under reaction conditions at atomic scale is critical for understanding reactivity. Elucidation of such insights on high surface area oxide supported metal nanoparticles has been limited by less than atomic resolution typically achieved by environmental transmission electron microscopy (TEM) when operated under realistic conditions and a lack of correlated experimental measurements providing quantitative information about the distribution of exposed surface atoms under relevant reaction conditions. We overcome these limitations by correlating density functional theory predictions of adsorbate-induced surface reconstruction visually with atom-resolved imaging by in situ TEM and quantitatively with sample-averaged measurements of surface atom configurations by in situ infrared spectroscopy all at identical saturation adsorbate coverage. This is demonstrated for platinum (Pt) nanoparticle surface reconstruction induced by CO adsorption at saturation coverage and elevated (>400 K) temperature, which is relevant for the CO oxidation reaction under cold-start conditions in the catalytic convertor. Through our correlated approach, it is observed that the truncated octahedron shape adopted by bare Pt nanoparticles undergoes a reversible, facet selective reconstruction due to saturation CO coverage, where {100} facets roughen into vicinal stepped high Miller index facets, while {111} facets remain intact.
authors.affiliation: Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.|Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States.
authors.forename: Talin
authors.initials: T
authors.lastname: Avanesian
authors.affiliation: Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.|Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States.
authors.forename: Sheng
authors.identifier: 0000-0001-5787-0179
authors.initials: S
authors.lastname: Dai
authors.affiliation: Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.|Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kale
authors.affiliation: Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.|Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States.
authors.forename: George W
authors.initials: GW
authors.lastname: Graham
authors.affiliation: Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.|Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Pan
authors.affiliation: Department of Chemical and Environmental Engineering, ⊥Program in Materials Science and Engineering, and #UCR Center for Catalysis, University of California Riverside , Riverside, California 92521, United States.|Department of Chemical Engineering and Materials Science and ∥Department of Physics and Astronomy, University of California Irvine , Irvine, California 92697, United States.
authors.forename: Phillip
authors.identifier: 0000-0002-4898-5510
authors.initials: P
authors.lastname: Christopher