Effect of (M = Co, Cu, Cr, and Mo) M/CeO2-MgO catalysts in selective catalytic reduction of NOx with hydrogen under excess oxygen condition

Abstract

Efficient NOx removal is an important for controlling air pollution, and developing effective catalysts is a significant challenge. In this study, (M = Co, Cu, Cr, and Mo) M/CeO2-MgO catalysts were prepared by the co-precipitation method followed by the wet-impregnation method for NO removal by H2-SCR technology. The catalysts were characterized by BET, XRD, XPS, TEM, and H2-TPR. The CeO2-MgO showed the BET surface area of 78 m2/g, which is slightly decreased after the impregnation of Cu, Co, Cr, and Mo metals. X-ray diffraction showed the presence of cubic phase by CeO2 and MgO. The Cu/CeO2-MgO catalyst shows the highest lattice strain, Ce3+ content, and adsorbed oxygen with values of 0.66%, 30.54%, and 74.12%. A maximum NOx conversion of 78% was achieved over the Cu/CeO2-MgO catalyst with a slightly large temperature window (100–250 ℃) among all the catalysts. The catalyst’s sequence of NOx conversion was as follows: Cu/CeO2-MgO > Mo/CeO2-MgO > Co/CeO2-MgO > Cr/CeO2-MgO > CeO2-MgO. The N2 selectivity followed the same order as NO conversion except for the Cr catalyst, which performed better than the Co impregnated catalyst.