Full Length ArticlePromotion effect of tungsten and iron co-addition on the catalytic performance of MnOx/TiO2 for NH3-SCR of NOx

- The addition of iron increased valence state of manganese.
- The addition of tungsten introduced new acid site.
- High temperature selectivity is significantly improved.
- Modified catalysts showed excellent SCR activity, selectivity and H2O resistance.

The influence of iron and tungsten in the Mn/Ti catalyst system on the activity and H2O induced deactivation was evaluated for the Selective Catalytic Reduction (SCR) of NO. The properties of the catalysts were characterized by physicochemical measurements, including BET surface area, X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), NH3 temperature-programmed desorption (NH3-TPD), NO oxidation, X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared spectroscopy (DRIFT) analyses. The results indicated that the addition of iron promoted surface species dispersion and increased valence state of manganese species, which enhanced the low-temperature activity. The addition of tungsten enhanced the acid sites and improved the thermal stability of the acid sites. Thus, the Mn10Fe10/W3Ti exhibited excellent NOx conversion and N2 selectivity during high temperature compared with Mn10/Ti and Mn10Fe10/Ti catalysts. Furthermore, the addition of tungsten exhibited excellent resistance to H2O induced deactivation. Accordingly, the co-addition of iron and tungsten with proper ratios to Mn/Ti resulted in excellent NOx conversion, N2 selectivity and H2O resistance.

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