The interaction of oxygen with ultrathin Ni deposits on yttria-stabilized ZrO2(100)

The interaction of oxygen with vapor-deposited Ni on yttria-stabilized ZrO2 (1 0 0) and the thermal stability of the oxygenated deposit were studied by XPS, UPS and CO TPD experiments. for two different Ni deposits. For 0.4 ML of Ni deposited at 300 K, the Ni 2p core level spectra show complete oxida tion above 1 1 0 L of O-2 at 300 K, whereas for 5 ML of Ni deposited at 570 K, the Ni2p and the UP spectra show that oxidation slowly approaches compl etion above 4500 L of O-2 at 420 K. Oxidation extends up to the NF state an d is accompanied by a drastic decrease of CO desorption temperature and des orbed amount. Upon annealing at increasing temperature, oxide decomposition is in both cases already complete at 870 K. At 700 K, the low-coverage Ni deposit has been reduced by more than 70%, whereas the high-coverage deposi t by less than 40%. The results are discussed in comparison with the well s tudied interaction of 0, with Ni monocrystals and a few available reports o n the oxidation of Ni clusters on other Substrates. (C) 2001 Elsevier Scien ce B.V. All rights reserved.