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

Abstract

A series of V 2O 5–TiO 2 aerogel catalysts were prepared by sol–gel method with subsequent supercritical drying with CO 2. The aerogel catalysts showed much higher surface areas and total pore volumes than V 2O 5–TiO 2 xerogel and impregnated V 2O 5–TiO 2 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 H 2S without harmful emission of SO 2. Temperature programmed reduction (TPR), XRD and Raman analyses revealed that the high catalytic performance of the aerogel catalysts originated from their highly dispersed VO x species and high reducibility.