Insights into enhancing SO2 tolerance for catalytic combustion of toluene over sulfated CeZrOx supported platinum catalysts

Supported platinum catalysts are widely used in the catalytic combustion of volatile organic compounds due to their excellent catalytic activity, but SO2 poisoning is one of the critical problems for the industrial application. In this work, a series of sulfated ceria-zirconia composite oxides (CeZrOx) supported platinum catalysts (Pt/CeZr-S) were prepared through the support sulfation strategy. In the catalytic combustion of toluene, the Pt/CeZr-S catalyst with 0.5 wt% Pt and 15 wt% sulfuric acid loading amounts exhibited the significantly increased activity compared with the reference Pt/CeZr catalyst. Moreover, the tolerance to SO2 poisoning of Pt/CeZr-S catalyst was greatly improved in the presence of 50 ppm SO2. Various characterization methods including XPS, NH3-TPD and in-situ DRIFTS were performed to reveal the structure-activity relationship and SO2 tolerance mechanism. The higher concentration of metallic Pt0 species resulting from the interaction of Pt species and acidic CeZr-S support contributed to the enhanced catalytic activity. Meanwhile, the increased acidity strength and total acidity amounts over Pt/CeZr-S catalysts could affect the sulfation process, resulting in significant inhibition of the adsorption and further accumulation of sulfur species.