The coadsorption of water and molecular oxygen on Ag(110): absence of OO bond activation by water

Abstract

The coadsorption of molecular oxygen and water on Ag(110) have been examined using temperature-programmed reaction mass spectrometry. We find no evidence for a reaction between water and molecularly chemisorbed oxygen, in contrast to a recent report concerning water and oxygen on Ag(111). The data do suggest, however, a mechanism for the competitive desorption and dissociation of molecularly adsorbed oxygen on Ag(110). O 2 dissociation appears to displace some molecularly adsorbed oxygen into the gas phase. Furthermore, sites for O 2 dissociation are blocked by coadsorbed water, thus leading to altered kinetics for desorption of O 2(a).