Analysis of Mn valence in the Mn based catalyst for NH3-SCR process

Abstract

A series of MnWO x /TiO 2 catalysts were prepared by liquid phase deposition. The MnWO x /TiO 2 catalyst was characterized by N 2 physical adsorption, X-ray diffraction, H 2 programmed temperature reduction, transmission electron microscopy and X-ray electron spectroscopy, and their NH 3-SCR performance were tested. The effect of Mn valence on the NH 3-SCR performance of MnWO x /TiO 2 catalyst was analyzed and discussed. The results show that the active components are uniformly dispersed on the surface, and the average valence of manganese are different. The average valence state of manganese in Mn 3 WO x /TiO 2 catalyst is the highest and the activity at low temperature is the best. On the contrary, the average valence of manganese in MnWO x /TiO 2 catalyst is the lowest while the N 2 selectivity is the best, which means that high valence of manganese is beneficial to its low temperature activity while low valence is favorable for its N 2 selectivity.