Selective oxidation of hydrogen sulfide containing excess water and ammonia over vanadia–titania aerogel catalysts

A series of V2O5–TiO2 aerogel catalysts were prepared by sol–gel method with subsequent supercritical drying with CO2. The aerogel catalysts showed much higher surface areas and total pore volumes than V2O5–TiO2 xerogel and impregnated V2O5–TiO2 catalysts. Two species of surface vanadium in the aerogel catalysts were identified by Raman measurements: monomeric vanadyl and polymeric vanadates. The selective oxidation of hydrogen sulfide in the presence of excess water and ammonia was studied over these catalysts. Aerogel catalysts showed very high conversion of H2S without harmful emission of SO2. Temperature programmed reduction (TPR), XRD and Raman analyses revealed that the high catalytic performance of the aerogel catalysts originated from their highly dispersed VOx species and high reducibility.