Adsorption of molecular oxygen on the Ag(111) surface: A combined temperature-programmed desorption and scanning tunneling microscopy study

B V Andryushechkin; V M Shevlyuga; T V Pavlova; G M Zhidomirov; K N Eltsov

doi:10.1063/1.5037169

Adsorption of molecular oxygen on the Ag(111) surface: A combined temperature-programmed desorption and scanning tunneling microscopy study

J Chem Phys. 2018 Jun 28;148(24):244702. doi: 10.1063/1.5037169.

Authors

B V Andryushechkin¹, V M Shevlyuga¹, T V Pavlova¹, G M Zhidomirov¹, K N Eltsov¹

Affiliation

¹ Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov St., 119991 Moscow, Russia.

PMID: 29960376
DOI: 10.1063/1.5037169

Abstract

The adsorption of O₂ on Ag(111) between 300 and 500 K has been studied with temperature-programmed desorption (TPD) and scanning tunneling microscopy (STM). At the first stage of adsorption, the disordered local oxide phase (commonly looking in STM as an array of black spots) is formed on the surface irrespective of the substrate temperature. The maximum concentration of black spots was found to be ≈0.11 ML, which corresponds to an oxygen coverage of ≈0.66 ML. Taking into account that the nucleation of the Ag(111)-p(4 × 4)-O phase starts after the saturation of the disordered phase, one can conclude that its coverage is at least not less than 0.66 ML. The analysis of STM and TPD data shows that the thermodesorption peak (m/e = 32) at 570 K is related exclusively to the decomposition of the p(4 × 4) phase, while the local oxide phase does not contribute to desorption.