Enhancement of NH-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 with NH (NH-SCR). The effects of transition metal modification were confirmed by means of XRD, BET, TEM, XPS, NH-TPD, and H-TPR measurements. Experimental results evidenced that CoMnAl-LDO presented the highest NO removal efficiency of over 80% and a relatively high N 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 HO and SO. The reasons for such results could be associated with the good dispersion of CoO and MnO , which could consequently provide optimum redox behavior, plentiful acid sites, and strong NO adsorption ability. Furthermore, dynamics calculations verified the meaningful reduction in apparent activation energy ( ) for the CoMnAl-LDO sample, which is in agreement with the DeNO activity.