An effective strategy to enhance the anti-poisoning ability of CeWTi catalyst for low-temperature selective catalytic reduction of NO with NH3

• Published in: Separation and purification technology Vol. 340; p. 126798
• Main Authors: Li, Mengqian, Huang, Xiaosheng, Zhang, Guodong, Tang, Zhicheng, Hu, Dongcheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2024
• Subjects: Ammonium bisulfate decomposition; Framework confined; Ordered mesoporous; Pore size; SO2 poisoning; Pore size; Ordered mesoporous; SO2 poisoning; Ammonium bisulfate decomposition; Framework confined
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.126798

Pore-size controlled ordered mesoporous CeWTix catalyst with framework confinement structure protected highly dispersed active sites from SO2 attacking. Importantly, the ordered mesoporous structure with larger pore sizes promoted the decomposition of ammonium bisulfate (ABS) at lower temperature, effectively alleviating the deposition behavior of ABS on the catalyst surface, thereby improving the catalyst's ability to resist SO2 poisoning. [Display omitted] •ABS poisoning had been investigated on pore-size controlled ordered mesoporous CeWTix catalyst.•Highly dispersed active sites were protected from SO2 attacking by framework confined structure.•Larger pore size could promote the decomposition of ABS at lower temperature. SO2 poisoning had long been recognized as the key to disrupting the longevity of SCR catalysts. The deposition of the toxic component ammonium bisulfate (ABS) on the catalyst was the main cause of its SO2 poisoning, so it was essential to active and promote the decomposition of ABS. In this study, the decomposition of ABS on catalyst surface was adjusted by controlling the pore size of ordered mesoporous catalyst. The results showed that the framework confined ordered mesoporous catalyst with larger pore size had stronger confinement effect on the active components Ce and W, which protected them from being attacked by sulfate group and ensured active components participating in SCR reaction effectively. In addition, according to the Kelvin equation, it was proved that the ABS deposited at a larger pore size would be subject to a larger surface vapor pressure, which would easily vaporize and decompose. This not only reduced the deposition of ABS, but also reduced the formation of metal sulfate from the conversion of ABS. Therefore, the framework confined ordered mesoporous CeWTix catalysts with larger pore sizes showed better SO2-resistance. This study provided a new path for the design of SCR catalysts with good SO2-resistance.