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The reaction scheme of O 2 with a Ni(110) surface is investigated from 133 to 703 K by low energy electron diffraction (LEED) and kinetic study. The phase diagram of the O/Ni(110) surface is presented by means of the LEED pattern variation as a function of the O 2 exposure in isothermal conditions. The adsorption kinetics of O 2 was quantitatively measured using a differentially pumped line of sight quadrupole mass spectrometer. When Ni(110) clean surface is exposed to the O 2 below 340 K, disordered NiO is formed. For exposure between 340 and 470 K, the surface reconstructs into the sequence of the (2 x 1) 1/2 and the (3 x 1) 2/3 ML missing-row structures, and thereafter a (9 x 5) suboxide structure develops followed by the growth of an epitaxial NiO(001) layer on top of the metal substrate. Between 470 and 570 K, after the formation of the (3 × 1) missing-row structure, extra O atoms penetrate into the Ni sublayer leaving the (3 x 1) structure on the surface, and finally a weak complicated LEED pattern is observed with NiO formation. Above 570 K, the excess surface O and extra chemisorbed O atoms dissolve into the bulk leaving the (2 × 1) structure on the surface. |
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