Selective catalytic reduction of NO x by low-temperature NH 3 over Mn x Zr 1 mixed-oxide catalysts.

Mn x Zr 1 series catalysts were prepared by a coprecipitation method. The effect of zirconium doping on the NH 3 -SCR performance of the MnO x catalyst was studied, and the influence of the calcination temperature on the catalyst activity was explored. The results showed that the Mn 6 Zr 1 catalyst exhibited good NH 3 -SCR activity when calcined at 400 °C. When the reaction temperature was 125-250 °C, the NO x conversion rate of Mn 6 Zr 1 catalyst reached more than 90%, and the optimal conversion efficiency reached 97%. In addition, the Mn 6 Zr 1 catalyst showed excellent SO 2 and H 2 O resistance at the optimum reaction temperature. Meanwhile, the catalysts were characterized. The results showed that the morphology of the MnO x catalyst was significantly changed, whereby as the proportion of Mn 4+ and O α species increased, the physical properties of the catalyst were improved. In addition, both Lewis acid sites and Brønsted acid sites existed in the Mn 6 Zr 1 catalyst, which reduced the reduction temperature of the catalyst. In summary, zirconium doping successfully improved the NH 3 -SCR performance of MnO x .