A heterogeneous single Cu catalyst of Cu atoms confined in the spinel lattice of MgAl2O4 with good catalytic activity and stability for NO reduction by CO

Abstract

A heterogeneous single Cu catalyst of Cu atoms confined in the spinel lattice of MgAl₂O₄ (Cu₁-MgAl₂O₄) was prepared by a facile method. Cu₁-MgAl₂O₄ exhibits catalytic activity for NO reduction by CO that is much higher than that of 1.0 wt% Pt/CeO₂. Moreover, Cu₁-MgAl₂O₄ exhibits good catalytic stability at high reaction temperatures up to 700 °C during the long-term durability tests. The good stability is attributed to the confinement effect of the stable spinel lattice of Cu₁-MgAl₂O₄ that stabilizes the confined Cu atoms. The high catalytic activity is attributed to the fact that oxygen bonding to Cu atoms of Cu₁-MgAl₂O₄ participates in the oxidation of adsorbed CO with low activation energy, and the adsorption of NO on the resultant oxygen vacancies leads to the formation of N₂O with low activation energy, which subsequently decomposes to N₂.