High N 2 selectivity in selective catalytic reduction of NO with NH 3 over Mn/Ti-Zr catalysts.

A series of Mn-based catalysts were prepared by a wet impregnation method for the selective catalytic reduction (SCR) of NO with NH 3 . The Mn/Ti-Zr catalyst had more surface area, Lewis acid sites, and Mn 4+ on its surface, and showed excellent activity and high N 2 selectivity in a wide temperature range. NH 3 and NO oxidation was investigated to gain insight into NO reduction and N 2 O formation. The formation of N 2 O was primarily dominated by the reaction of NO with NH 3 in the presence of O 2 via the Eley-Rideal mechanism. An intimate synergistic effect existed between the Mn-based and the Ti-Zr support. It was demonstrated that the Ti-Zr support greatly promoted the catalytic performance of Mn-based catalysts.