CHARACTERISTICS AND COMBUSTION DECOMPOSITION ACTIVITIES OF CUO/MORDENITE/

Various amounts of copper oxide were loaded by impregnation of copper salt solution on dealuminated mordenites and redox-treated at 500 degr ees C and 750 degrees C. The catalysts were characterized by XRD, ESR, H-2-TPR and O-2-TPD, and tested for the combustion of methane, aceton e, benzene and l-hexene, and NO decomposition. The redox-treatment ind uced most of the copper to exist as a CuO crystallite on the mordenite and its reducibility decreased as the temperature increased. Redox-tr eatment at 750 degrees C reduced the crystallinity of the mordenite an d increased the size of the CuO crystallite, especially for the sample s with a higher CuO content. The optimum amount of copper for the comb ustion was 3-5 wt.%. However, the activity of the NO decomposition inc reased with the amount of CuO present. Maximum activities were observe d for both the combustion and the NO decomposition when the ratio of s ilica/alumina was 20 similar to 30. These results suggest that forming CuO crystallites, including clusters and ion exchanged Cu2+ ions, on dealuminated mordenite by the impregnation of copper salt is desirable for the preparation of the catalysts for combustion/NO decomposition. (C) 1997 Elsevier Science B.V.