Very high activity and selectivity could be achieved for the direct oxidation of H2S into elemental sulfur at low reaction temperature (40-60 degrees C), on nickel sulfide supported SiC catalyst. The heterogeneous nature of the support surface (hydrophilic and hydrophobic areas) could explain the important role played by water to maintain a high and stable H2S conversion level. The formation of a very active superficial nickel oxysulfide phase was proposed in order to explain the activation period necessary at reaction temperatures <60 degrees C. Total selectivity for sulfur was attributed to the very low reaction temperature and the absence of any microporosity in the support.