Understanding the single and dual deactivation factors effect on NH3-SCR catalyst

Abstract

Nitrogen oxides (NO_x) are pollutants that cause atmospheric pollution, selective catalytic reduction technology (NH₃-SCR) with catalyst as the core technology have been widely used in the process of NO_x removal because of its stability and high efficiency. However, various deactivation factors in flue gas (K, SO₂, Pb, and etc.) present significant challenges to the application of catalysts. To encounter the challenges of catalysts deactivation, this review first summarizes the causes of deactivation from single factors and strategies to mitigate their effects, emphasizing the importance of protecting redox sites and acid centers to enhance catalyst resistance. More importantly, the effect of a single deactivation factor on the catalyst does not properly represent the deactivation behaviors of catalysts. Consequently, this review also summarized the impact of dual deactivation factors on catalysts, highlighting that complex interactions between poisoning substances and the catalyst play a critical role in determining whether deactivation is compensatory or aggravated. Emphasizing that adjusting the composition of catalytic active sites to favor compensatory effects is considering as a novel strategy for designing catalysts under flue gas with complex chemical composition. By integrating mechanistic insights from single and dual deactivation factors on catalysts, this review hopes to deepen the understanding of catalyst deactivation under complex flue gas conditions and provide a serious guiding for the design of advance catalysts with high resistance to deactivation.