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)
