H2S oxidation by oxygen over V2O5Al2O3, V2O5/TiO2, V2O5/SiO2, V2O5/Al2O3/TiO2 catalysts was studied at the temperature below the sulfur dew-point. High activity and the oscillation nature of the oxidation process were demonstrated for the catalysts with low V2O5 contents (2-5 wt.%) supported on Al2O3, TiO2 or a combination thereof. An increase in the V2O5 concentration up to 10-20 wt.% resulted in lowering of the catalytic activity and oscillation ability. The oscillations were not determined using V2O5/SiO2 and pure V2O5 catalysts. Difference between pure V,05, catalysts with high- and low-loaded V2O5 catalysts was accounted for by the structure of V5+ species formed in catalysts. The high activity of the catalysts with the low vanadium content supported on Al2O3, TiO2 or combinations thereof was attributed to vanadium species bound directly to the surface. (C) 2002 Elsevier Science B.V. All rights reserved.