Selective oxidation of hydrogen sulfide to sulfur on vanadium-based catalysts containing tin and antimony

Oxidation of hydrogen sulfide to sulfur was investigated over a series of mixed-metal oxide catalysts containing vanadium, tin, and antimony. These catalysts were prepared by a coprecipitation method. V/Sn/Sb ternary oxides exhibited 100% sulfur yield over a wide range of temperature (180-240 degreesC when weight hourly space velocity was 0.0245 mol of H2S/g of catalyst per h), which was superior to the binary oxides of V/Sn, V/Sb, and Sn/Sb. In addition, V/Sn binary oxides had a better sulfur yield than the corresponding single oxides. Far V/Sn and V/Sn/Sb catalysts, Brunauer-Emmett-Teller measurements indicated that catalyst surface areas increased linearly with the Sn/N atomic ratio and temperature-programmed reduction studies showed that the reducibility of VOx species increased with the tin content. These two factors should contribute to the better catalytic behaviors of the V/Sn and V/Sn/Sb catalysts in H2S oxidation. The presence of 30 vol % water vapor decreased the catalyst activity but had little effect on the maximum sulfur yield. Results of X-ray diffraction and scanning electron microscopy suggested that the ternary oxide catalysts were stable during the reaction.