Temp.-programmed desorption of NO (TPD) and temp.-programmed redn. 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 expts. can det. the temp. range in which the deNOx 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 expts. show that Et alc. is a more active reductant in the deNOx process than propene. The max. of NOx conversion is higher with Et alc. used as a reductant in both cases of investigated catalysts. Moreover, the temp. of the max. degree of NOx redn. is lower in the case of alc. used as an reductant. Co3O4 is a more active and suitable catalyst for the deNOx process than CoFe2O4. [on SciFinder(R)]