Novel regenerated V- and Ce-mixed oxide modified catalysts for the NH3-SCR of NOx displaying a distinctive broad temperature window. (1st January 2023)

• Record Type: Journal Article
• Authors: Huang, Jiajin; Chen, JiaYu; Yao, Jinze; Zhao, Siyao; Wu, Xingbei; Xia, Qibin
• Is Part Of: Journal of cleaner production. Volume 382(2023)
• Publication Date: 2023-01-01
• Subjects: NH3-SCR -- Regenerated spent SCR Catalyst -- V–Ce mixed Oxides -- Reaction mechanism; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2022.135384
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: The challenge for selective catalytic reduction (SCR) of NO x with NH3 is to improve de-NO x activity at low temperatures while simultaneously improving the tolerance of catalysts towards SO2 poisoning. Herein, V and Ce oxides were loaded on deactivated SCR catalysts subjected to acid pickling (CAT) via impregnation to recover de-NO x activity. The resulting V–Ce@CAT catalyst exhibited 85–95% NO x conversions over a wide temperature window of 200–450 °C while conversions of only 40–78% over the same temperature range were observed with CAT (spent catalyst treated with acid). Interestingly, in addition to the high tolerance towards SO2 displayed by V–Ce@CAT, the catalyst exhibited improved reactivity after the introduction of 200 ppm SO2, with the NO x conversion increasing from 80% to 87%. The results indicated that a kinetic equilibrium was reached between the formation and decomposition rates of Ce2 (SO4 )3 on V–Ce@CAT which prevented the accumulation of surface sulfate species, thereby protecting the main active species V from catalytic inactivation. Furthermore, in situ DRIFTS revealed that the NH3 -SCR reaction pathway of V–Ce@CAT follows the L-H mechanism. Graphical abstract: Image 1 Highlights: High-performance NH3 -SCR of NO x was obtained with regenerated SCR catalysts modified with V and Ce mixed oxides. The regenerated catalysts shows broad working temperature windows (150–450 °C). The SO2 tolerance was attributed to the preferential formation of sulfate upon introduction of Ce species. The interaction between V and Ce enhanced the ratio of surface chemisorbed labile oxygen (Oα ), which promoted oxidation.