Mesoporous MnOx-CeO composites for NH-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 mixed oxides for selective catalytic reduction (SCR) of NO with NH. The catalyst prepared from the oxalate route showed improved performance for NOx conversion and SO + HO durability. To further improve the SO and HO 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 temperature-programmed reduction (H-TPR), NH temperature-programmed desorption (NH-TPD), SO temperature-programmed desorption (SO-TPD), and diffuse reflectance infrared fourier transform spectroscopy ( DRIFTS). The nickel-manganese-cerium ternary oxide showed the best SO and HO durability. The reason can be ascribed to its smaller pores, amorphous structure, and moderate amount of surface Mn/oxygen species, which could decrease chemical adsorption of SO.