Low-temperature NH3-SCR performance of La2O3-modified V2O5-WO3/TiO2 catalyst
The rare earth metal oxide La2O3 was introduced to modify the V2O5-WO3/TiO2 catalyst to improve its low-temperature catalytic performance.By adjusting the La2O3 content and calcined tempera-ture,and using a series of characterization methods such as XRD,BET,SEM,TEM,NH3-TPD,H2-TPR and XPS,the intrinsic correlation between the structure of La2O3-V2O5-WO3/TiO2 catalyst and its NH3-SCR performance in the low temperature range was discussed.The results showed that the La2V6W5/TiO2 catalyst had the best activity.Using 90％NO conversion as the criteria,the lower limit of the temperature window extended to 160 ℃.Its activity improvement was attributed to the addition of La2O3,which increased the concentration of V4+in the catalyst to improve the redox capacity and increase the oxygen vacancies on the surface,thereby improving the low-temperature performance of the catalyst.
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