BaTi0.8Cu0.2O3 Catalysts for NO Oxidation and NOx Storage: Effect of Synthesis Method

Abstract

The effect of the synthesis method (sol–gel or hydrothermal) in the physicochemical properties of a BaTi0.8Cu0.2O3 catalyst with perovskite structure was analyzed and the catalytic performance for the NO–NO2 oxidation and for the NOx storage was tested. The characterization of catalysts by BET, ICP-OES, XRD, XPS and H2-TPR reveals that only the sol–gel process allows the incorporation of copper into the perovskite structure, and that, by using the hydrothermal method, highly dispersed CuO is deposited on the surface of the BaTiO3. The NOx storage cyclic (NSC) experiments, carried out using both catalysts, indicate that sol–gel catalyst shows a high NOx storage capacity at 400 °C whilst the hydrothermal catalyst exhibits a high NO to NO2 oxidation activity. For this reason, a double bed reactor configuration was tested for NSC experiments using the hydrothermal catalyst as the oxidation catalyst and the sol–gel catalyst as the NOx trap.