Cu-, Fe- and Ag-containing catalysts supported on γ-alumina, silica, SAPO-11 and Y-zeolite with 3 wt.% of metal loading were synthesized by the impregnation technique and characterized by N₂-adsorption, H₂-TPR and by the temperature-programmed desorption (TPD) of ammonia and NO. Additionally the textural properties, acidity and adsorption capacity of parent support materials were determined by above-described methods. The adsorption capacity of NO_x (AC_NOx) was quantified in the temperature range of 373 K to 823 K in continuous flow of NO + O₂ and after saturation with NO at 90 °C in the presence of oxygen excess. It was found that the NO_x uptake decreased as the temperature increased with maximum at 373 K. Total uptake of NO_x depended on the type of transition metal, the content of Al in the support material, acidic site density and surface area. Two NO_x desorption regions were found by TPD experiments over γ-Al₂O₃ after exposure to either a NO and O₂ or NO₂-containing gas, i.e., in a temperature range from 420 K to 500 K and from 550 K to 800 K. The latter one corresponds to a desorption of differently bonded NO_x species. In-situ diffuse reflectance infrared fourier transform (DRIFT) spectroscopy of γ-alumina, 3Ag/Al₂O₃, 3FeO/Al₂O₃ and 3CuO/Al₂O₃ in the presence of NO and excess O₂ shows that NO is mainly adsorbed in the form of nitrates and that it is oxidized to NO₂ above 673 K. Catalysts containing Cu and Fe oxides show a higher activity for the oxidation of NO to NO₂ than the Ag-containing counterparts. Ag, Cu and Fe oxides supported on silica possess a lower AC_NOx in comparison to alumina- and zeolite-supported samples. The determined value of NO adsorption capacity allowed rationalizing some of the earlier results on selective catalytic reduction (SCR) of NO_x in the presence of ethanol.