Mechanochemical localization of vanadia on titania to prepare a highly sulfur-resistant catalyst for low-temperature NH3-SCR

• Published in: Applied catalysis. B, Environmental Environmental, 2023-05, Vol.324, p.122290, Article 122290
• Main Authors: Hwang, Keon Ha, Park, Namjun, Lee, Hwangho, Lee, Kyung-Min, Jeon, Se Won, Kim, Hyun Sub, Lee, Yongkyu, Kim, Tae Jin, Lee, Won Bo, Kim, Do Heui
• Format: Article
• Language: English
• Subjects: Ammonium bisulfate deposition; Density functional theory; NH3-selective catalytic reduction; V2O5/WO3-TiO2; Vanadia localization
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.122290

This paper reports a novel attempt to mechanochemically localize vanadia on the surface of WO3-TiO2 by physically grinding high-vanadia-loading V2O5/WO3-TiO2 with WO3-TiO2. On the surface of the vanadia-localized catalysts, clustered vanadia sites exhibited enhanced activity for low-temperature (< 250 °C) NH3-selective catalytic reduction (NH3-SCR) by forming polymeric structures. The catalyst with localized vanadia simultaneously exhibited superior sulfur resistance, which has not been achieved in conjunction with high activity via conventional synthesis. Mechanochemical interactions between clustered vanadia and titania resulted in the formation of TiO2 sites adjacent to the vanadyl species without deforming the polymeric structure of the vanadia. Density functional theory calculations showed that ammonium bisulfate (ABS) was considerably more stable in the presence of exposed TiO2 adjacent to the vanadyl species. The exposed TiO2 sites absorbed the deactivating material ABS from the clustered vanadia sites, which prevented the blockage of the catalytic active sites, leading to less deactivation. [Display omitted] •Vanadia localized catalysts were prepared by using mechanochemical method.•The catalysts show high activity and sulfur resistance simultaneously.•Clustered vanadia form polymeric structures leading to high activity.•TiO2 sites generated during mechanochemical synthesis lead to high sulfur resistance.•Ammonium bisulfate migrates from the vanadia active sites to adjacent TiO2 sites.