Investigation of oxide catalysts activity in the NOx neutralisation with organic reductants

Temperature-programmed desorption of NO (TPD) and temperature-programmed reduction of NO by propene and ethanol (TPSR) over the catalyst with redox properties and the structure of spinels - Co₃O₄ and CoFe₂O₄ - were investigated.The TPD experiments can determine the temperature range in which the deNO_x proceeds and provide information about the heat of adsorption of NO on the surface of catalysts. The values of the adsorption heat are much higher in the case of the catalyst with weaker redox properties (CoFe₂O₄), because of stronger bonds between the adsorbate and the surface of catalyst. The TPD and TPSR experiments show that ethyl alcohol is a more active reductant in the deNO_x process than propene. The maximum of NO_x conversion is higher with ethyl alcohol used as a reductant in both cases of investigated catalysts. Moreover, the temperature of the maximum degree of NO_x reduction is lower in the case of alcohol used as an reductant. Co₃O₄ is a more active and suitable catalyst for the deNO_x process than CoFe₂O₄.