Catalytic activity of Cu/η-Al2O3 catalysts prepared from aluminum scraps in the NH3-SCO and in the NH3-SCR of NO

Abstract

Copper-loaded η-alumina catalysts with different copper contents were prepared by impregnation/evaporation method. The catalysts were characterized by XRD, FTIR, BET, UV-Vis, and H₂-TPR and evaluated, for the first time, in the selective catalytic reduction of NO by NH₃ and in the selective catalytic oxidation of NH₃. The characterization techniques showed that the impregnation/evaporation method permits to obtain highly dispersed copper oxide species on the η-alumina surface when a low amount of copper is used (1wt. % and 2 wt.%). The wet impregnation method made it possible to reach a well dispersion of the copper species on the surface of the alumina for the low copper contents Cu(1)-Al₂O₃ and Cu(2)-Al₂O₃. The latter justifies the similar behavior of Cu(1)-Al₂O₃) and Cu(2)-Al₂O₃ in the selective catalytic oxidation of NH₃ where these catalysts exhibit a conversion of NH₃ to N₂ of the order of 100% at T> 500 °C.

Keywords: Cu/η-Al2O3; H2-TPR; NH3-SCO; NH3-SCR; TEM.