A general strategy for design SCR catalysts with enhanced resistance to multiple poisons through constructing highly dispersed paired acid-base sites.

The complex composition of solid waste in co-processing within industrial kilns leads to the coexistence of multiple poisons in flue gas, which accelerates the deactivation of SCR catalysts. In this work, solid superacid modified CeO2 with highly dispersed acid-base sites was constructed, achieving the capture of acidic/basic poisons. Moreover, the designed catalyst retained active sites for the adsorption and activation of NH3 after poisoning. The sulfated ZrO2/CeO2 exhibited 2.0, 1.1, 2.3, 1.2, and 2.6-fold increase of NOx conversion than commercial V2O5-WO3/TiO2 when Pb, As, Zn, K, and Cd loading. The highly dispersed monodentate sulfate species on the catalyst surface provided abundant acid sites for the capture of basic poisons (e.g., Cd, Pb, K, Zn) and NH3 adsorption. The basic CeO2 doped with Zr captured acidic poisons (e.g., As) and promoted the activation of NH3 due to the high capacity of Ce3 + and oxygen vacancies. Spectroscopic characterization revealed that the highly dispersed acid-base sites along with more Ce3+ species on the catalyst surface facilitated the adsorption and activation of NH3, crucial for the formation of the reaction intermediate NH2NO. This work may provide an approach to develop efficient SCR catalysts with superior resistance to poisons and reduce the generation of waste catalysts.