The Copoisoning Effects of Antimony and Ammonium Bisulfate on Ceria-Based Catalysts for NO_<i>x</i> Reduction

In this study, the underlying influence mechanism between Sb and ABS on ceria-based SCR catalysts has been disclosed. Experimental results indicate that there exists a copoisoning effect between antimony (Sb) and ammonium bisulfate (ABS) on SCR activity, which significantly suppresses NO conversion below about 40% within the whole investigated temperature window. Characterization results deduced that the copoisoning effect should be derived from the existing strong interactions between Sb and ABS. Inherently, the formed interactions not only result in pronounced deactivation in structural properties and redox capacity but also counteract the acidity enhancement provided by sulfate species from ABS. Importantly, the restrained mobility of active oxygen species would hinder reaction between NO and NH4+ from ABS, while the narrowed pore size and existence of interactions could strengthen the thermal stability of ABS, therefore resulting in more serious deactivation of SCR performances.