Ce-Fe bimetallic oxide catalysts for CO catalytic oxidation at a high concentration of SO₂

A series of Ce-Fe bimetallic oxide catalysts were prepared by a hydrothermal method for CO catalytic oxidation at a high concentration of SO2 in this paper. Ce0.7Fe0.3 showed the highest catalytic performance in CO oxidation, reaching higher than 97% CO conversion at above 300 degrees C in the flue gas containing 1000 ppm CO. When the concentration of SO2 in the flue gas increased to 1000 mg m(-3), the CO conversion of Ce0.7Fe0.3 remained 86% for 10 hours. The doping of Fe into the CeO2 lattice resulted in the formation of a CeO2-like solid solution and the increase in the oxygen vacancy concentration in Ce0.7Fe0.3, thus facilitating the CO oxidation activity of Ce0.7Fe0.3. In the flue gas containing SO2, the doping of Fe showed positive effects of resisting the change in crystallinity and mitigating the loss of pore structure. The sulfation of CeO2 could lead to the formation of Ce-2(SO4)(3) on the surface, which deactivated the catalyst. The doping of Fe inhibited the reduction of Ce4+ to Ce3+ by SO2, thereby preventing the formation of Ce-2(SO4)(3). Furthermore, a small amount of sulfate was deposited on the surface of Ce0.7Fe0.3, exhibiting poorer thermal stability than that deposited on CeO2. The Fe-doping modification played a positive role in enhancing the CO oxidation activity and SO2-poisoning resistance of Ce0.7Fe0.3.