Novel V2O5–CeO2/TiO2 catalyst with low vanadium loading for the selective catalytic reduction of NOx by NH3

• V2O5–CeO2/TiO2 catalyst is much more active than V2O5/TiO2 for the NH3-SCR.
• The addition of Ce enhances the alkali resistance of V2O5/TiO2 catalyst.
• The formation of reactive NO2 and monodentate nitrate species can be promoted by Ce.
• The redox cycle (V4+ + Ce4+ ↔ V5+ + Ce3+) plays a key role for the NH3-SCR of NOx.

The effect of Ce on the activity and alkali resistance of V2O5/TiO2 catalyst for the selective catalytic reduction (SCR) of NOx by NH3 has been investigated. It was found that the addition of Ce not only reduced the vanadium loading of V2O5/TiO2 but also enhanced its activity and alkali resistance. The NOx conversion over 0.5%V2O5-5%CeO2/TiO2 was much higher than that over 1%V2O5/TiO2 catalyst. Based on the catalyst characterization, the redox cycle (V4+ + Ce4+ ↔ V5+ + Ce3+) can account for the excellent NH3-SCR catalytic performance of 0.5%V2O5–5%CeO2/TiO2 catalyst. In situ diffuse reflectance infrared transform spectroscopy (DRIFTS) measurements revealed that the role of Ce on the V2O5–CeO2/TiO2 catalyst was to contribute to the formation of NO2 and monodentate nitrate species, both of which were reactive intermediates for the NH3-SCR of NOx.

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