Lifting the Pt{100} surface reconstruction through oxygen adsorption: A density functional theory analysis

Abstract

The adsorption of atomic oxygen on unreconstructed Pt[100]-(1 x 1) and reconstructed Pt[100]-(5 x 1) was modeled using density-functional theory in an attempt to understand the relative stability of the unreconstructed phase as a function of oxygen coverage. Our calculations showed that at zero temperature the (5 x 1) is more stable than the unreconstructed (1 x 1) phase at zero oxygen coverage. However, oxygen absorption on the Pt[100]-(5 x 1) phase removed the reconstruction, reversing the phase stability. Using thermochemical analysis, we show desorption of oxygen corresponding to a temperature near 730 K, consistent with experimentally observed desorption peaks for oxygen covered (1 x 1) surfaces. These results have ramifications for understanding the full Pt[100](1 x 1)-->Pt[100]hex-R0.7 degrees surface phase transition.