Feature ArticleNb-modified Mn/Ce/Ti catalyst for the selective catalytic reduction of NO with NH3 at low temperature

- Mn/Ce/Nb/Ti showed superior NH3-SCR performance in a wider temperature range.
- The addition of Nb increased the specific surface area and the amount of surface acid sites.
- Nb modification promoted the NO oxidation while restrained the NH3 oxidation.

Mn/Ce/Ti and Mn/Ce/Nb/Ti catalysts were synthesized using a precipitation method and their catalytic activities for NO selective reduction with NH3 at low temperatures were evaluated. Nb doping not only improved the activity of the catalyst over a wide temperature range but also restricted the generation of NO2 and N2O. The Mn/Ce/Nb/Ti catalyst displayed 100% NO conversion from 150 to 250 °C and >90% N2 selectivity below 250 °C. The specific surface area of the catalyst was increased and its surface acidity was strengthened after Nb doping. Moreover, Nb doping increased the NO oxidation ability and lowered the NH3 oxidation activity of the catalyst. All the above factors contributed to enhancing the overall NH3-SCR performance of the Mn/Ce/Nb/Ti catalyst compared with that of the Mn/Ce/Ti one. The long-term stability and resistance to H2O and SO2 of the Mn/Ce/Nb/Ti catalyst were also evaluated.

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