Quantum chemistry and molecular dynamics were used to evaluate the performance of solid oxide fuel cell anode materials in the presence of H-2 and H2S. The most common anode material Ni-yttria-stabilized zirconia (Ni-YSZ) was used for the study. It was found that the presence of H2S has an important effect on the oxidation of H-2. Thermodynamics and transport limitations favor the oxidation of H-2 instead of H2S. Furthermore it is predicted that the presence of H2S slows down the oxidation of the hydrogen due to transport limitations (the H2S molecules tend to be surrounded by H-2 molecules in the media). (c) 2006 The Electrochemical Society.