Title

Hydrogen Adsorption on Ordered and Disordered Pt-Ni Alloys

Publication Date

7-27-2020

Department

Materials Science and Engineering; Chemical and Biological Engineering; Physics and Astronomy; Ames Laboratory

Campus Units

Ames Laboratory, Materials Science and Engineering, Chemical and Biological Engineering, Physics and Astronomy

OSTI ID+

1645121

Report Number

IS-J 10277

DOI

10.1007/s11244-020-01338-4

Journal Title

Topics in Catalysis

Volume Number

63

First Page

714

Last Page

727

Abstract

The bulk properties and chemical reactivity of disordered Pt-Ni alloys in the A1 (fcc) structure are investigated using different methods: Virtual Crystal Approximation (VCA), Korringa–Kohn–Rostoker Coherent Potential Approximation (KKR-CPA), and large explicit supercells generated using Super-Cell Random Approximates (SCRAPs). While VCA predicts lattice constants that closely follow Vegard’s law, the large supercells and KKR-CPA predict lattice constants that are consistently larger than Vegard’s law. KKR-CPA results closely agree with those from the large supercells for the disordered alloys, producing similar projected density of states and magnetic moment across the composition range. For instance, while VCA predicts the disordered alloys to be non-magnetic at a Pt concentration (xPt) ≥ 0.5, KKR-CPA and SCRAPs predict the disordered alloys to remain ferromagnetic to higher Pt concentrations. As xPt decreases, the adsorption of H becomes more exothermic on bulk-terminated (111) surfaces but less exothermic on Pt monolayer-terminated (111) surfaces due largely to strain effects. (111) surfaces cut from the large supercells predict average H adsorption energies on the disordered alloys similar to those on the ordered phases of the same compositions, while VCA predicts H adsorption to be more exothermic.

DOE Contract Number(s)

SC0018408; AC02-07CH11358; AC02-05CH11231

Language

en

Department of Energy Subject Categories

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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