Abstract: A series of Cu-Mg-Al hydrotalcite compounds with M (II) :Al (III) molar ratio of 3 : 1 were prepared by co-precipitation method. Corresponding mixed oxides were obtained after calcination 500 ℃（wCuO(％)= 0, 5, 10, 20, denoted as w-CMAO, w=0, 5, 10, 20）. Pt/Cu-Mg-Al-O catalysts were prepared by impregnation with H2PtCl6 solution. XRD results showed that Cu was well dispersed in the catalysts and their precursors. NO_x storage performance was investigated using NO_x adsorption experiment at constant temperature, and decomposition of stored NO_x was also studied by TPD method. It was shown that although MgO content was decreased due to Cu addition, the activity of NO oxidation was improved, and NO_x storage performance was increased effectively. TPD results further showed that the decomposition temperature of nitrate formed on the catalysts can be reduced sharply when w=10％～20％ of CuO was added.

Key words: Nitrogen oxide, Hydrotalcite, NO_x storage, Lean burn, Pt/Cu-Mg-Al-O