Identification of Hydroxyl Groups on Au Surfaces Formed by H2O(a) + O(a) Reaction

Water adsorption and reaction on an O(a)-covered Au(997) surface were comprehensively investigated by means of thermal desorption spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy. Adsorbed water is stabilized by O(a) adatoms on Au(997), and the surface reaction between H2O(a) and O(a) occurs at 105 K to form surface hydroxyl groups that were unambiguously identified by their feature at 10.9 eV below the Fermi level in the UPS spectra. Upon heating, surface hydroxyl groups react to produce H2O and O(a). These results elucidate the elementary surface reactions between water and oxygen adatoms on Au surfaces at the molecular level and greatly deepen the fundamental understanding of the unique role of water in Au-catalyzed oxidation reactions.