Stability of water monolayers on Ru(0001): Thermal and electronically induced dissociation
نویسندگان
چکیده
To clarify conflicting reports on the composition and stability of H2O and D2O adsorbates on Ru(0001), we have conducted correlated experiments in two laboratories using X-ray photoelectron spectroscopy and thermal desorption spectroscopy, without and after controlled electron irradiation. Both species form molecular wetting layers; D2O stays molecular to desorption while H2O undergoes a thermal conversion that has been interpreted as partial dissociation. Electron impact leads to this conversion for both H2O and D2O with very high cross-sections (in the high 10 16 cm range at 100–200 eV) and low threshold energies. These effects may explain discrepancies
منابع مشابه
Monodisperse microisland formation on Ni/Ru(0001) monolayers.
The creation of identical microislands consisting of Ni trimers and multiples thereof on Ru(0001) induced by oxygen adsorption has been observed using scanning tunnelling microscopy. The island formation is caused by an oxygen induced expulsion of Ni atoms or trimers out of the moiré-distorted (densified) Ni monolayer. The exceptional stability of the Ni trimers is attributed to oxygen attachme...
متن کاملOxygen adsorption on Pt/Ru(0001) layers.
Chemical properties of epitaxially grown bimetallic layers may deviate substantially from the behavior of their constituents. Strain in conjunction with electronic effects due to the nearby interface represent the dominant contribution to this modification. One of the simplest surface processes to characterize reactivity of these substrates is the dissociative adsorption of an incoming homo-nuc...
متن کاملExperimental evidence for a partially dissociated water bilayer on Ru[0001].
Core-level photoelectron spectra, in excellent agreement with ab initio calculations, confirm that the stable wetting layer of water on Ru[0001] contains O-H and H2O in roughly 3:5 proportion, for OHx coverages between 0.25 and 0.7 ML, and T<170 K. Proton disorder explains why the wetting structure looks to low energy electron diffraction (LEED) to be an ordered p(square root of 3 x square root...
متن کاملWater and CO (co-)adsorption on pseudomorphic Pt films on Ru(0001) - a low-temperature scanning tunneling microscopy study.
Coadsorption of CO and water under ultrahigh vacuum (UHV) conditions can be considered as a model system for the interaction of metal surfaces with CO in an aqueous electrochemical environment. Nevertheless, this has rarely been investigated, and in particular for catalytically relevant bimetallic systems, there is hardly any information available. Here we report results of a low-temperature sc...
متن کاملHigh-resolution electron energy-loss measurements of sticking coefficients of methane decomposition on Ru( 0001)
A new approach, utilizing an elevated pressure reactor and high-resolution electron energy loss spectroscopy (HREELS), to the measurement of sticking coefficients of methane decomposition on Ru(0001) has been demonstrated. It has been shown that the detection, by Auger electron spectroscopy and photoelectron spectroscopy, of fractional monolayers of carbon on ruthenium is difficult because of t...
متن کامل