Hydroxyl formation on Ag(110) studied by HREELS

Abstract

The coadsorption system Ag(110) O H 2 O is known to give rise to well defined OH layers in a thermally activated process between 190 and 220 K. In a high resolution EELS study we have found that the (1 × n), n = 3,2 ordered layers produced from the ( n × 1), n = 6,4 reconstructed Ag(110)O surface are characterized by very sharp loss peaks at 277 cm −1 ( v(MOH)) and 3390 cm −1 ( v(OH)). The dominant M-OH loss exhibits essentially the same halfwidth as the specular peak, whereas the OH bending mode at 675 cm −1 is significantly broadened and shows a shoulder at 755 cm −1. The (1 × 1)-OH phase formed from the (2 × 1)-O-reconstructed phase is less stable than the lower coverage OH layers. Such studies may play an important role in understanding the mechanism of this almost unique stoichiometric reaction.