High-Temperature Selective Oxidation of H2S to Elemental Sulfur on a β-SiC-Supported Cerium Catalyst

H2S-selective catalytic oxidation at high temperatures is a cost-effective way to directly treat lean acid gas. Herein, cerium supported on a beta-SiC catalyst was synthesized by a simple impregnation method, and the catalytic behavior for the H2S-selective oxidation reaction was evaluated at a relatively high-temperature range (300-550 degrees C). The 10%CeO2/beta-SiC catalyst exhibited excellent H2S conversion (93%) and outstanding sulfur selectivity (94%) at 300 degrees C and could maintain it at 82 and 87%, respectively, even at temperatures up to 550 degrees C. Remarkably, the catalyst revealed prominent reaction stability, which could proceed consecutively at 550 degrees C for 30 h and could also run circularly from 300 to 550 degrees C three times without notable deactivation. This demonstrated that the beta-SiC support allowed good dispersion of CeO2 particles, which further improved the reducibility of the 10% CeO2/beta-SiC catalyst. Furthermore, the abundant oxygen vacancies on the catalyst surface facilitated O-2 activation by providing a large amount of surface adsorbed oxygen and by improving the lattice oxygen mobility. Particularly, the high thermal stability of the beta-SiC support displayed a significant role in high-temperature reactions, and the strong Ce-O-Si interaction between the beta-SiC support and the CeO2 phase allowed the catalyst a good resistance to SO2 poisoning. This work provides a prospective way for the treatment of lean acid gas.