The adsorption and thermal decomposition of water on clean and oxygen-predosed Al(111)

Abstract

The adsorption of water on both clean and oxygen-predosed Al(111) has been studied by vibrational spectroscopy using electron energy loss spectroscopy (EELS). At 130 K, adsorption on either surface is competitively associative and dissociative. The dominant dissociation product is a hydroxyl species. On the clean surface, adsorption is predominantly molecular, while in the presence of oxygen, adsorption is predominantly dissociative. In contrast to the low temperature behavior, adsorption of water on clean Al(111) at 300 K is completely dissociative, resulting in oxygen adsorption and surface oxidation. Adsorbed hydroxyl species can be produced at 300 K by prolonged water exposure. Upon heating a low-temperature water layer adsorbed on either surface, molecular water desorption and further decomposition both occur. The production of adsorbed hydroxyl species from water reaches a maximum at 250 K on the clean surface and at 350 K on the oxygen-predosed surface. The hydroxyl species decompose above these temperatures to evolve hydrogen and further oxidize the Al(111) surface.

Adsorption and dissociation of H2O on Al(1 1 1) surface by density functional theory calculation

“…From the PDOS analysis, it is clear that the bonding between the O and metal surface is mainly ionic. [17] suggested that adsorption is predominantly molecular on the clean surface at low temperature, while in the presence of oxygen, adsorption is predominantly dissociative. They also found that the production of adsorbed hydroxyl species from water reaches a maximum at 250 K on the clean surface and at 350 K on the oxygen-predosed surface.…”

Surface oxidation of Al-Cu-Fe alloys: a comparison of quasicrystalline and crystalline phases

“…This characteristic of H 2 O is well known from UHV studies of oxidation of Al and its alloys (Eberhardt and Kunz 1978, Netzer and Madey 1983, Crowell et al 1987, McConville et al 1987, Pansoy-Hjelvik et al 1998). There, the e ect is related to enhanced formation of oxides which contain OH groups, such as AlO(OH) or Al(OH) 3 (Textor and Grauer 1983).…”

Origin of H− in collisions of hydrogen atoms with an adsorbate-covered Cu(100) surface

“…While the residual gases in the chamber consisted predominantly of H 2 O and H 2 , molecular hydrogen is expected to be inconsequential at the Cu surface due to a dissociative adsorption barrier 32,33 of ϳ1 eV, while the residual water vapor absorbs readily with binding energies of up to a few electron volts. 18,[34][35][36] The formation of H − , therefore, is associated primarily with the re-adsorption of residual water vapor on the copper surface.…”