Campus Units

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

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

7-27-2020

Journal or Book Title

Topics in Catalysis

Volume

63

First Page

714

Last Page

727

DOI

10.1007/s11244-020-01338-4

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.

Comments

This is a post-peer-review, pre-copyedit version of an article published in Topics in Catalysis. The final authenticated version is available online at DOI: 10.1007/s11244-020-01338-4. Posted with permission.

Copyright Owner

Springer Science+Business Media, LLC

Language

en

File Format

application/pdf

Available for download on Tuesday, July 27, 2021

Published Version

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