Growth and structures of MnOx thin films on Ni(1 1 1)

Abstract

Ultra-thin MnOx films were prepared by evaporating metallic Mn onto a Ni(111) surface followed by annealing in an O2 atmosphere. The structures of the surfaces were studied by Auger electron spectroscopy (AES), Low energy electron diffraction (LEED), High-resolution electron energy loss spectroscopy (HREELS), and X-ray photoelectron spectroscopy (XPS). Significantly different structures are formed by annealing/oxidation at different temperatures. A Ni(111)-(√3 × √3)-R30° monolayer structure formed by annealing at 840 K. Increasing the annealing temperature to 950 K, significantly different loss features in HREELS, as well as a much lower AES ratio of Mn/Ni, were observed, which could be proposed to the formation of a NiMnOx -like interface structure on Ni(111). The MnOx/Ni(111) film can promote to passivate the Ni substrate again oxidation, which can not only serve as a model catalytic surface but also inspire a new idea for metal anti-corrosion.