Excellent operating temperature window and H 2 O/SO 2 resistances of Fe-Ce catalyst modified by different sulfation strategies for NH 3 -SCR reaction

Expecting to gain an excellent operating temperature window and superior catalytic activity of the catalyst in SCR reaction, the Fe-Ce bimetallic oxide catalyst was firstly prepared and sulfated with two different sulfation strategies by H 2 SO 4 . It is interestingly found that both the two sulfation strategies can significantly broaden the operating temperature window of the catalyst. In particular, the SFC and FCS both exhibit superior resistance to H 2 O + SO 2 , and the NO x conversion of the SFC even displays no changes in the coexistence of H 2 O and SO 2 . The characterization results show that different sulfation strategies can generate amorphous sulfate species rather than bulk sulfate species. Furthermore, more surface-adsorbed oxygen as well as higher contents of Ce 3+ and Fe 3+ can be obtained on the sulfated catalysts, especially for the SFC catalyst. Meanwhile, different sulfation strategies will progressively enhance the redox ability and amounts of strong acid sites, which will contribute to broadening the operating temperature window for the NH 3 -SCR reaction. Additionally, different sulfation methods do not change the reaction pathway of catalysts. However, the adsorption of ad-NH 3 species and reactivity of ad-NO x species are significantly changed. These lead to the reaction pathway shifts to E - R direct over the SFC and the promotion of E - R and L – H mechanisms over the FCS catalyst.