Structure-dependent catalytic oxidation of H2S over Na2CO3 impregnated carbon aerogels

Na2CO3 impregnated carbon aerogels were developed as high-performance catalysts for low temperature oxidation of H2S. The microporous and mesoporous structures of carbon aerogels were tuned by CO2 activation and the sol-gel conditions, respectively, to investigate their roles in the catalytic performance for H2S oxidation. After desulfurization, micropores were completely blocked and mesopores were partially filled by the oxidation products. The space utilization of mesopores decreased with the increase of mesopore sizes, and the catalytic performance achieved the best at a compromise between the mesopore volumes and mesopore sizes. CO2 activation caused the development of micropores. Consequently, the catalytic performance and space utilization of mesopores were both improved greatly. The high catalytic performance should be attributed to the unique intra-particle micropores and inter-particle mesopores of carbon aerogels, in which micropores act as the reactors for H2S oxidation and mesopores serve as the major storehouse of products. (C) 2011 Elsevier Inc. All rights reserved.