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

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 vanadialocalized catalysts, clustered vanadia sites exhibited enhanced activity for low-temperature (< 250 degrees C) NH3selective 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.

Automated summary

This paper reports a novel attempt to mechanistically localize vanadia on the surface of WO3-TiO2 by physically grinding high-vanadia-loading V2O5/WO3-TiO2 with WO3-TiO2. The localized vanadia catalysts exhibited enhanced activity for low-temperature NH3-SCR by forming polymeric structures. The mechanochemical interactions between clustered vanadia and titania resulted in the formation of adjacent TiO2 sites without deforming the polymeric structure of the vanadia, leading to superior sulfur resistance and less deactivation.