Cu2+-acetate exchanged X zeolites: Preparation, characterization and N2O decomposition activity

In this contribution a series of Cu–X zeolite catalysts were prepared utilizing ion exchange from solution method using copper(II) acetate. The calcination was affected for 3 h at air atmosphere at 550 °C. Characterization of the obtained catalysts was carried out utilizing IR, XRD, SEM, elemental analyses, N2-adsorption, and electrical conductivity techniques. Drastic structural as well as textural changes take place after ionic exchange. Increasing copper acetate initial concentration leads to a gradual crystallinity loss together with the formation of amorphous phase. Meanwhile, Si/Al ratio of the zeolite showed a slight decrease. The observed crystallinity loss was attributed to the decrease in the solutions pH values which, in turns, favors the dealumination. Textural analysis revealed that increasing the copper ions concentration is accompanied by elimination of micropores together with the development of mesopores. Moreover, continuous decrease in SBET, micropore surface area and micropore volume was also observed. The activity of the various catalysts was tested towards nitrous oxide decomposition. The obtained results revealed that the N2O decomposition activity is related to the crystallinity loss as well as the relative conductivity decrease upon the admission of N2O over the different catalysts.

N2O decomposition was studied over a series of Cu–X zeolite catalysts prepared via ion exchange from solution. Drastic structural as well as textural changes take place when Na–X zeolite is treated with a solution of copper acetate followed by calcination. Such changes are reflected in the catalysts N2O decomposition activity.Figure optionsDownload as PowerPoint slideResearch highlights
► Gradual crystallinity loss with increasing copper acetate initial concentration.
► Elimination of micropores together with the development of mesopores.
► N2O decomposition activity correlates with in situ electrical conductivity.