MnOx-support interactions in catalytic bodies for selective reduction of NO with NH3

Catalytic bodies for selective reduction of NOx with NH3 based on MnOx, TiO2 and sepiolite as active phase, support, and binder, respectively, were prepared. The same amount of MnOx (5 w%) was added by impregnation of the precursor over a 70/30 titania/sepiolite. One catalyst was obtained by wet equilibrium impregnation of the pre-shaped support, while the other was prepared by incipient wetness impregnation of the TiO2 and then mixed with the binder and the PGA, and finally extruded. In order to study the role of the binder in the catalytic system, four models were also synthesized. According to characterization data and to catalytic activity results, sepiolite not only confers the rheological properties needed for extrusion, but it also modifies the physicochemical properties of the catalysts: it modulates the acidity and the NOx adsorption capacity and lability, and, depending on the synthesis procedure, it enhances catalytic activity.