Issue 19, 2020

Thermodynamics of the formation of surface PtO2 stripes on Pt(111) in the absence of subsurface oxygen

Abstract

This paper examines the thermodynamics of PtO2 stripes formed as intermediates of Pt(111) surface oxidation as a function of the degree of dilation parallel to the stripes, using density functional theory and atomistic thermodynamics. Internal energy calculations predict 7/8 and 8/9 stripe structures to dominate at standard temperature and pressure, which contain 7 or 8 elevated PtO2 units per 8 or 9 supporting surface Pt atoms, respectively. Moreover, we found a thermodynamic optimum with respect to mean in-stripe Pt–Pt spacing close to that of α-PtO2. Vibrational zero point energies, including bulk layer contributions, make a small but significant contribution to the stripe free energies, leading to the 6/7 stripe being most stable, although the 7/8 structure is still close in free energy. These findings correspond closely to experimental observations, providing insight into the driving force for oxide stripe formation and structure as the initial intermediate of platinum surface oxidation, and aiding our understanding of platinum catalysts and surface roughening under oxidative conditions.

Graphical abstract: Thermodynamics of the formation of surface PtO2 stripes on Pt(111) in the absence of subsurface oxygen

Supplementary files

Article information

Article type
Paper
Submitted
16 sep 2019
Accepted
30 okt 2019
First published
30 okt 2019
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2020,22, 10634-10640

Thermodynamics of the formation of surface PtO2 stripes on Pt(111) in the absence of subsurface oxygen

S. Hanselman, I. T. McCrum, M. J. Rost and M. T. M. Koper, Phys. Chem. Chem. Phys., 2020, 22, 10634 DOI: 10.1039/C9CP05107D

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