A Caltech Library Service

Adsorption of Atomic H and O on the (111) Surface of Pt_3Ni Alloys

Jacob, Timo and Goddard, William A., III (2004) Adsorption of Atomic H and O on the (111) Surface of Pt_3Ni Alloys. Journal of Physical Chemistry B, 108 (24). pp. 8311-8323. ISSN 1520-6106. doi:10.1021/jp049971h.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


To determine the optimal structure and size of a cluster suitable for modeling chemical processes on the (111) surface of Pt_3Ni alloys and to understand how alloying changes the electronic structure, we used the B3LYP flavor of density functional theory (DFT) to study systematically the composition and the characteristics of the Pt/Ni(111) alloy surface for clusters up to 44 atoms. We find that the bulk structure (Pt_3Ni crystal) has the atoms cubic closest packed as in bulk Pt or bulk Ni, but ordered such that each Ni has 12 bonds to Pt atoms and we find that this same pattern is preferred on the (111) surface. As a result, the ordered (111) surface has each Ni surrounded by six Pt atoms. After determining the optimal cluster, we examined the chemisorption of atomic hydrogen and atomic oxygen at all on-top (μ_1), bridge (μ_2), and 3-fold (μ_3) sites on the (111) alloy surface. We find that oxygen binds most strongly at a fcc site (two Pt and one Ni atom) with an adsorption energy of 3.50 eV, which is 0.22 eV stronger than binding to the pure Pt(111) surface. The barrier for the O to migrate about fcc sites shared by the same Ni is 0.23 eV, but to hop over to a site bordering a different Ni is 0.53 eV. In contrast, the barrier on Pt(111) is 0.56 eV. Thus oxygen is much more localized on the Pt/Ni alloy surface than on pure Pt. A similar behavior was observed for the chemisorption of hydrogen. Here we find that the best site is on-top of Pt with D_e = 2.67 eV, which is comparable to pure Pt(111). In contrast to Pt(111) where the barrier for migration through the bridge and fcc sites is only 0.06 eV, making H very mobile, we find that on Pt/Ni(111) the adsorption energies range from 1.78 to 2.67 eV. Here the migration of the H from one Pt site to the next goes through the bridging and fcc sites sharing a Ni with a barrier of 0.12 eV, twice that for Pt(111).

Item Type:Article
Related URLs:
URLURL TypeDescription
Goddard, William A., III0000-0003-0097-5716
Additional Information:© 2004 American Chemical Society. Received: January 2, 2004; In Final Form: April 15, 2004. Publication Date (Web): May 21, 2004. T.J. gratefully acknowledges support by the German academic exchange service (DAAD). This work was also supported by General Motors (Gerald Voecks). The computation facilities of the MSC have been supported by grants from ARO-DURIP, ONR-DURIP, NSF (MRI, CHE), and IBM-SUR. In addition, the MSC is supported by grants from DoE ASCI, ARO-DARPA, ONR-MURI, NIH, ONR, ChevronTexaco, Seiko-Epson, Beckman Institute, and Asahi Kasei.
Funding AgencyGrant Number
Deutscher Akademischer Austauschdienst (DAAD)UNSPECIFIED
Army Research Office (ARO)UNSPECIFIED
Office of Naval Research (ONR)UNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Caltech Beckman InstituteUNSPECIFIED
Issue or Number:24
Record Number:CaltechAUTHORS:20170510-074719783
Persistent URL:
Official Citation:Adsorption of Atomic H and O on the (111) Surface of Pt3Ni Alloys Timo Jacob and William A. Goddard, III The Journal of Physical Chemistry B 2004 108 (24), 8311-8323 DOI: 10.1021/jp049971h
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77327
Deposited By: Tony Diaz
Deposited On:16 May 2017 20:51
Last Modified:15 Nov 2021 17:30

Repository Staff Only: item control page