Characterization of copper species over Cu/SAPO-34 in selective catalytic reduction of NO x with ammonia: Relationships between active Cu sites and de-NO x performance at low temperature

• DOI: 10.1016/j.jcat.2012.09.020
• Publication Date: 2012-11-14T17:45:34Z
• Authors: Junjie Xue; Xinquan Wang; Gongshin Qi; Jun Wang; Meiqing Shen; Wei Li
• Keywords: Selective catalytic reduction; Atmospheric temperature range

Abstract To investigate the active Cu sites in the selective catalytic reduction of NO by NH 3 (NH 3 SCR) over Cu/SAPO-34 catalysts, a series of samples containing different Cu loadings has been prepared by an ion-exchange process. A combination of H 2 TPR and EPR techniques was applied to identify and quantify the isolated Cu 2+ sites. The trend of the isolated Cu 2+ ions in the samples estimated by EPR is similar to that from TPR results and was found to be proportional to the NH 3 SCR reaction rates. The turnover frequency (TOF) calculated based on the number of isolated Cu 2+ ions on samples with varying Cu loadings showed a constant value at the same temperature. Thus, we conclude that the isolated Cu 2+ species associated with the six-ring window and displaced into the ellipsoidal cavity of SAPO-34 (Site (I)) are the active sites for the NH 3 SCR reaction in the temperature range 100–200 °C.