Preparation, characterisation and catalytic performance for soot oxidation of copper-containing ZnAl 2O 4 spinels

Abstract

Copper-containing ZnAl 2O 4 catalysts have been properly prepared by the glycothermal method, with copper loaded within the mixed oxide structure (catalyst Zn 0.95Cu 0.05Al 2O 4) or impregnated in the previously prepared support ZnAl 2O 4 (catalyst 5%Cu/ZnAl 2O 4). The samples were characterised by XRD, HRTEM, SEM-EDAX, N 2 adsorption at −196 °C, FT-IR, and H 2-TPR, and the catalytic combustion of soot under NOx/O 2 was tested. The mixed oxides, with confirmed spinel structure, consist of nanoparticles with around 5–12 nm. The impregnated catalyst is more active for soot combustion than both the bare support and the substituted catalyst, which is attributed to the proper reducibility of copper that catalyses the NO oxidation to NO 2. This catalyst is also highly selective towards CO 2 formation as soot combustion product.