A novel regeneration method for deactivated commercial NH3-SCR catalysts with promoted low-temperature activities

Yan, Zheng; Yu, Jingyao; Liu, Huan; Ke, Xin; Wang, Chunyong; Liu, Lili; Wei, Lihong; Yang, Tianhua

A novel regeneration method for deactivated commercial NH3-SCR catalysts with promoted low-temperature activities

2020

A novel route is developed for regeneration of deactivated commercial NH₃-SCR catalysts, which includes an initial in situ construction of anatase TiO₂ porous film, followed by loading of MnOₓ, CeOₓ, and Mn-Ce mixed oxides as active components. The regenerated catalysts present largely improved low-temperature denitrification performance due to the synergetic effect of MnOₓ and CeOₓ. The denitrification efficiency could reach a high value of 97% at 200 °C and 100% at 250 °C when the Ce-Mn mixed oxides are loaded at the optimized molar quantity ratio of 10:9 (Ce:Mn). Properties and reaction mechanisms of the regenerated catalysts are investigated with characterizations of X-ray photoelectron spectroscopy (XPS), NH₃ temperature-programmed desorption (NH₃-TPD), H₂ temperature-programmed reduction (H₂-TPR), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Our results demonstrate that the adsorption and oxidation of NO plays a crucial role for these three catalysts even though a difference exists on the reaction pathways. Graphical abstract

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