Mesoporous MnOx-CeO 2 composites for NH 3 -SCR: the effect of preparation methods and a third dopant.

In this study, different preparation methods including an oxalate route, a nano-casting strategy and a traditional co-precipitation route were applied to obtain MnOx-CeO 2 mixed oxides for selective catalytic reduction (SCR) of NO with NH 3 . The catalyst prepared from the oxalate route showed improved performance for NOx conversion and SO 2 + H 2 O durability. To further improve the SO 2 and H 2 O resistance of catalysts, ternary oxides were prepared from the oxalate route. The catalysts were studied by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), H 2 temperature-programmed reduction (H 2 -TPR), NH 3 temperature-programmed desorption (NH 3 -TPD), SO 2 temperature-programmed desorption (SO 2 -TPD), and in situ diffuse reflectance infrared fourier transform spectroscopy ( in situ DRIFTS). The nickel-manganese-cerium ternary oxide showed the best SO 2 and H 2 O durability. The reason can be ascribed to its smaller pores, amorphous structure, and moderate amount of surface Mn 3+ /oxygen species, which could decrease chemical adsorption of SO 2 .