Enhancement of NH(3)-SCR performance of LDH-based MMnAl (M = Cu, Ni, Co) oxide catalyst: influence of dopant M

Transition metal (Cu, Ni, Co) doped MnAl mixed oxide catalysts were prepared through a novel method involving the calcination of hydrotalcite precursors for the selective catalytic reduction of NO(x) with NH(3) (NH(3)-SCR). The effects of transition metal modification were confirmed by means of XRD, BET, TEM, XPS, NH(3)-TPD, and H(2)-TPR measurements. Experimental results evidenced that CoMnAl-LDO presented the highest NO(x) removal efficiency of over 80% and a relatively high N(2) selectivity of over 88% in a broad working temperature range (150–300 °C) among all the samples studied. Moreover, the CoMnAl-LDO sample possessed better stability and excellent resistance to H(2)O and SO(2). The reasons for such results could be associated with the good dispersion of Co(3)O(4) and MnO(x), which could consequently provide optimum redox behavior, plentiful acid sites, and strong NO(x) adsorption ability. Furthermore, dynamics calculations verified the meaningful reduction in apparent activation energy (E(a)) for the CoMnAl-LDO sample, which is in agreement with the DeNO(x) activity.