A surface EXAFS study of thin nickel deposits on (110) TiO2 surfaces

The first stages of nickel deposition on a clean (110) TiO2 surface were studied using surface extended X-ray absorption fine structure (EXAFS). Experiments were performed on two kinds of nickel deposits, one of 0.8 equivalent monolayers and another of 1.6 equivalent monolayers. Depositions were performed on well characterized TiO2 (110)-p(1 x 1) surfaces. The correlation of Auger experiments with EXAFS results showed that no islands were present on the surface; only two-dimensional growth of nickel was observed. Moreover, it was shown, in the case of the thinner deposit, that a model with nickel atoms forming chains in the channels determined by oxygen atoms on the surface is consistent with the EXAFS data. (C) 1997 Elsevier Science S.A.