Ceria accelerates ammonium bisulfate decomposition for improved SO2 resistance on a V2O5-WO3/TiO2 catalyst in low-temperature NH3-SCR

Abstract

BackgroundAmmonia bisulfate (ABS) deposition on the active sites of the catalyst surface is the main reason for SO2 poisoning in low-temperature NH3-selective catalytic reduction (SCR). Accelerated ABS decomposition efficiently enhances the SO2 resistance. MethodsIn this work, ceria was specifically chosen to decorate V2O5-WO3/TiO2 catalyst (Ce-VW/Ti) to activate ABS decomposition in low-temperature NH3-SCR. Significant findingsThe optimal 7Ce-VW/Ti catalyst accelerated the decomposition of ABS and had superior SO2 tolerance at 250°C. The additive CeO2 improved the specific surface area and surface acidity, favoring the NH3-SCR catalytic activity. ABS was preferentially deposited on the additive CeO2 on the surface of the 7Ce-VW/Ti catalyst and generated cerium sulfate, eventually protecting the active V2O5 sites and TiO2 support. Moreover, high quantity of V5+ and charge transfer between active species V2O5 and support TiO2 could be maintained due to CeO2 protection, subsequently maintaining the high NH3-SCR performance and enhancing the SO2 tolerance.