Abstract
AbstractThe oxidation of a clean Mo surface with different caesium oxide overlayers has been studied by means of x‐ray photoelectron spectroscopy. The results show that the presence of a caesium oxide overlayer produces enhanced oxidation of Mo at room temperature when compared with thermal oxidation, and that a layer of MoO3 is formed on top of the Mo substrate. The thickness of this MoO3 layer depends on the thickness of the caesium oxide overlayer. Also, true catalytic oxidation has been observed when the substrate with the caesium oxide overlayer is exposed to oxygen at room temperature. The interface of the MoO3 layer with the Mo metal consists of about five monolayers of Mo suboxide MoOx (with x ∼2) when the oxidation has been performed at room temperature. At moderate temperatures (∼400 K) this interface is smoother, although it tends to decrease in thickness with time. A mechanism of catalytic oxidation that is consistent with the experimental data is proposed. This mechanism is controlled by diffusion of oxygen through the caesium oxide overlayers and through the Mo substrate. Also, a diffusion of Cs towards the surface has been detected. Different phases of the type MoO3−δ can explain the chemical shifts observed in the Mo6+ XPS spectra.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
