The comparative study on the catalytic activity of Cu–M/Ce0.8Zr0.2O2 (M = W, Nb, Cr and Mo) catalysts with dual-function for the simultaneous removal of NO and CO under oxygen-rich conditions

Abstract

A series of Cu–M/Ce_0.8Zr_0.2O₂ (M = W, Nb, Cr and Mo) catalysts were synthesized by a co-impregnation method, aiming for the removal of NO and CO under oxygen-rich conditions. The activity experiments confirmed that Cu–M/Ce_0.8Zr_0.2O₂ can simultaneously catalyze NH₃-SCR reaction and CO oxidation reaction. Moreover, the difference in the catalytic activity of the Cu–M/Ce_0.8Zr_0.2O₂ catalysts was investigated by a series of characterization techniques. The results suggested that the sequence of the ratio of Cu⁺/Cu on the surface of the catalysts was as follows: 10Cu10CrCZ > 10Cu10NbCZ > 10Cu10WCZ > 10Cu10MoCZ, and the redox performance of Cu–M/Ce_0.8Zr_0.2O₂ was consistent with this sequence. Besides, the introduction of Cr did not significantly improve the surface acidity as compared with the introduction of W, Nb and Mo. Excellent NH₃-SCR and CO oxidation activity depended on the appropriate surface acidity and redox performance. Thus, 10Cu10NbCZ showed the most excellent NH₃-SCR and CO oxidation activity.