The interaction of hydrogen sulfide with a cermet composed of zirconium oxide and yttrium oxide doped with metallic nickel (Ni) in the stoichiometric form Zr0.92Y0.08O2-delta/40 vol% Ni and a pure nickel metal was studied at 500 and 650 degrees C utilizing high temperature X-ray photoelectron spectroscopy and high-temperature scanning electron microscopy. The hydrogen sulfide (H2S) did not appear to interact with the cermet at 500 degrees C with H,S exposures of 6 x 10(-5) Torr for I h, but interaction of H2S with the cermet was observed at 650 degrees C at similar H2S exposures. The amount and the rate of reaction of H2S were significantly lower with the cermet than with the pure nickel metal at 650 degrees C with similar HS exposures. The dispersion of nickel in the zirconium and yttrium oxide matrix decreased the reaction of HS with nickel in the cermet. (c) 2004 Elsevier B.V. All rights reserved.