Effects of impregnation sequence on the NH3-SCR activity and hydrothermal stability of a Ce-Nb/SnO2 catalyst.

• A Ce-Nb/SnO2 catalyst with excellent NH3-SCR activity and hydrothermal stability was synthetized by simple impregnation method. • The impregnation sequence can affect the activity and hydrothermal stability of the catalyst. • The developed Ce-Nb/SnO2 catalyst can be used for the NOx removal from diesel and hydrogen-fueled engines. Hydrothermal stability is crucial for the practical application of deNO x catalyst on diesel vehicles, for the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR). SnO 2 -based materials possess superior hydrothermal stability, which is attractive for the development of NH 3 -SCR catalyst. In this work, a series of Ce-Nb/SnO 2 catalysts, with Ce and Nb loading on SnO 2 support, were prepared by impregnation method. It was found that, the NH 3 -SCR activities and hydrothermal stabilities of the Ce-Nb/SnO 2 catalysts significantly varied with the impregnation sequences, and the Ce-Nb(f)/SnO 2 catalyst that firstly impregnated Nb and then impregnated Ce exhibited the best performance. The characterization results revealed that Ce-Nb(f)/SnO 2 possessed appropriate acidity and redox capability. Furthermore, the strong synergistic effect between Nb and Sn species stabilized the structure and maintained the dispersion of acid sites. This study may provide a new understanding for the effect of impregnation sequence on activity and hydrothermal stability and a new environmental-friendly NH 3 -SCR catalyst with potential applications for NO x removal from diesel and hydrogen-fueled engines. [Display omitted] [ABSTRACT FROM AUTHOR]