Effect of sulfur poisoning on Co3O4/CeO2 composite oxide catalyst for soot combustion

CeO2, Co3O4, and a series of Co3O4/CeO2 composite oxides prepared by co-precipitation were exposed to SO2 under an oxidizing environment at 400 °C. These fresh and SO2-poisoned samples were characterized by in situ diffuse reflectance infrared Fourier transform spectroscopy, X-ray diffraction, temperature-programmed desorption, and X-ray photoelectron spectroscopy. Sulfates were formed on the oxides, with more sulfates on CeO2 than on Co3O4. On the Co3O4/CeO2 composite oxides, both cobalt sulphate and ceria sulfate were formed. Fresh and sulfated samples were tested for soot combustion in a NO/O2 gas flow. The Co3O4/CeO2 composite oxides showed better SO2 tolerance and higher activity than CeO2 but were more easily poisoned by SO2 than Co3O4.

Graphical AbstractCo3O4/CeO2 composite oxides showed better SO2 tolerance and higher activity than CeO2 but was more easily poisoned by SO2 than Co3O4 during soot combustion in NO/O2.Figure optionsDownload full-size imageDownload as PowerPoint slide