Promotional effect of Ba additives on MnCeO x /TiO 2 catalysts for NH 3 -SCR of NO at low temperature

A series of Ba-modified MnCeO x /TiO 2 catalysts were prepared by a wet impregnation method and tested for selective catalytic reduction (SCR) of NO with NH 3 at low temperature. The results showed that Ba additives obviously improved the catalytic performance of the MnCeO x /TiO 2 catalyst for NH 3 -SCR, and the BaMnCeO x /TiO 2 catalyst with 3 wt% BaO exhibited the optimal catalytic performance. Moreover, the introduction of Ba also improved the resistances toward water vapor and SO 2 of catalysts. The N 2 adsorption, H 2 -TPR, and X-ray photoelectron spectroscopy results showed that the addition of Ba increased the specific surface area, redox properties, and concentrations of surface Mn 4+ and chemisorbed oxygen of catalysts. Furthermore, NH 3 -TPD and NO-TPD were used to investigate the absorption of NH 3 and NO on the catalyst. The results revealed that although the introduction of Ba significantly promoted the adsorption of NO, it also inhibited the adsorption of NH 3 . Consequently, the catalytic performance of MnCeO x /TiO 2 was greatly improved with the Ba additives.