IR studies of the interaction of water with lanthanum oxide surfaces

摘要

Reflection IR spectroscopy has been used to study the adsorption of water on ordered epitaxial layers of lanthanum oxide grown on a Cu(1 1 1)substrate. Isotopic studies demonstrate conclusively that adsorption is dissociative and involves the conversion of surface oxygen anions to hydroxyl groups. There is direct spectroscopic evidence that these surface hydroxyl groups may exchange with gas phase water at 300 K. In the absence of isotopic labelling, however, there is no evidence from IR spectroscopy for the formation of two distinct types of hydroxyl groups differing in their coordination to the lanthanum ions, thus suggesting that adsorption is accompanied by surface reconstruction. (C) 2000 Elsevier Science B.V. All rights reserved. References: 12