Water adsorption on the hydroxylated H-(1 × 1) O-ZnO(0001̄) surface

Abstract

The adsorption of water multilayers on a well defined single crystal, hydroxyl-terminated ZnO-surface, H(1x1)-O-ZnO(0001) surface has been investigated using infrared (IR) spectroscopy, helium atom scattering (HAS) and X-ray photoelectron spectroscopy (XPS). The results reveal the formation of well ordered mono-, bi- and multilayers of D2O and H2O on this substrate. On the bare hydroxyl-covered H(1x1) surface the OH-stretch vibration could be clearly identified in the IR-spectra. The water adsorption and desorption kinetics on this hydroxylated surface were studied by monitoring the reflectivity of the surface for helium atoms. The analysis of the data yielded activation energies for desorption of H2O from the H(1x1) O-ZnO surface of 55.2 kJ mol-1. The results reveal the formation of ordered mono- and bilayers. Further exposure to water at 113 K results in the formation of amorphous 3-D islands.

Nanoparticulate Dye-Semiconductor Hybrid Materials Formed by Electrochemical Self-Assembly as Electrodes in Photoelectrochemical Cells

“…The IR spectrum of the OH stretching region of a ZnO(000-1) shows the vibrational band at 3572 cm −1 that is unique for the ZnO surface. The signals at 3648 cm −1 and 3615 cm −1 are due to absorptions from some of the optical components as shown by reference measurements without ZnO [24]. These experiments provide the first direct evidence that the O-ZnO(000-1) is hydrogen terminated under the chosen experimental conditions.…”

The surface chemistry of ZnO nanoparticles applied as heterogeneous catalysts in methanol synthesis

“…Concerning the oxygen-terminated ZnOð0 0 0 1Þ surface, it was found that a completely hydrogen-free surface undergoes a (1 Â 3) reconstruction [78,79]. The adsorption of hydrogen [79], as well as the adsorption of water [80] readily caused the formation of a H(1 Â 1) overlayer on this surface. The overlayers were found to be indistinguishable from each other [80].…”

“…The adsorption of hydrogen [79], as well as the adsorption of water [80] readily caused the formation of a H(1 Â 1) overlayer on this surface. The overlayers were found to be indistinguishable from each other [80]. In a STM study of hydrogen adsorption on ZnOð1 0 1 0Þ, an ordered (1 Â 1) adlayer of H atoms was identified, in which the H atoms are located on top of the oxygen atoms of the oxide surface [81].…”

Enhanced Antibacterial Activity of Nanocrystalline ZnO Due to Increased ROS‐Mediated Cell Injury

“…As far as we are aware, there is no comprehensive report concerning the mechanism by which ROS, and particularly hydroxyl radicals, are formed on the zinc oxide surface, [28,36] although some investigations of the nature of the ZnO surface, such as chemisorbed OH species after interaction with water, have been published. [68,69] In addition, little is known about the nature of defect sites on a wet metal oxide surface.…”

“…Given that (surprisingly) little is known about the water-zinc oxide interaction, [36] it may be assumed that a complex surface chemistry is involved in generating these oxyradicals. The fact that nanometer-scale ZnO is considerably more efficient than micrometer-scale particles at killing bacteria becomes apparent from the findings reported here.…”