Leakage of ${\mathrm{O}}_{2}$ Precursor Molecules from Inert Hydrogen Islands on a Pt(111) Surface

Leakage of $O_{2}$ Precursor Molecules from Inert Hydrogen Islands on a Pt(111) Surface

K. Gustafsson and S. Andersson

Phys. Rev. Lett. 97, 076101 – Published 17 August 2006

Abstract

We have observed, using infrared spectroscopy, that the precursor-mediated $O_{2}$ chemisorption on the clean and the partially hydrogen-covered Pt(111) surfaces exhibits opposite temperature dependencies above the temperature for stable $O_{2}$ physisorption. While the chemisorption probability on the clean surface increases with increasing temperature due to thermal activation of the precursor, it decreases on the partially hydrogen-covered surface which we suggest is due to a general loss of the mobile precursor molecules by thermal desorption from chemically inert hydrogen islands.