Influence of sodium on MnOx/TiO2 catalysts for SCR of NO with NH3 at low temperature

Abstract

MnOx/TiO2 catalysts doped with sodium were prepared using the impregnation method. According to the results of the selective catalytic reduction (SCR) of NO with NH3, sodium had the strong poisoning effect on MnOx/TiO2 catalysts for NO decomposition. With the help of XRD, H2-TPR, NH3-TPD, TGA and FESEM, the structures and properties of the catalysts were characterised. Results indicated that the addition of sodium would weaken the role of active ingredients in the SCR process. Meanwhile, the reduction peaks of MnOx/TiO2 catalysts doped with sodium slightly shifted to higher temperatures with increasing content of sodium, attributing to the sintering of MnOx and sodium oxides. Based on the FESEM images, some larger particles were observed on the surface after sodium doping, which might be attributed to compounds of sodium manganese oxides. It could be concluded that the addition of sodium decreased the SCR activity of catalyst by slashing electron donation from the MnOx active site.