Deactivation effect of different Pb salts over Fe/Zr-W catalyst for selective catalytic reduction of NO with NH₃

Deactivation on NH₃-SCR catalyst surface by heavy metal species continues to hinder it long-term usage lifetime in flue gas treatment. A deeper insight into the poisoning effect of different Pb species on catalysts is crucial for designing denitrification catalysts with anti-Pb property. Herein, the obtained Fe/Zr-W catalyst was modified through multiple Pb salts (Pb(NO₃)₂, PbCl₂, and PbSO₄) to assess the different impact caused by various Pb species. The results showed that different Pb species led to varying levels of catalyst deactivation. Pb(NO₃)₂ and PbCl₂ caused different degrees of deactivation in the Fe/Zr-W catalyst, associated with the decrease in redox cycling capacity, acidic sites, and surface adsorption oxygen. However, PbSO₄ inversely enhanced the acidic site density of catalyst, which favored NH₃ adsorption but significantly decreased the conversion selectivity in catalytic process. Possible deactivation pathway differentiation among Pb salts over Fe/Zr-W catalyst was established. This work revealed insights into the different poisoning pathway of various Pb salts, contributing to the development of denitration catalysts with enhanced Pb tolerance.