(216b) Insights into the Deactivation of Cu/SAPO-34 By Low- and High-Temperature Hydrothermal Treatment
To gain insights into the similarity and difference between low- and high-temperature deactivation mechanisms, model Cu/SAPO-34 catalysts with varying Cu loadings were prepared using a one-pot method. These catalysts were further hydrothermally treated at either 70 or 800 °C. Effects of hydrothermal treatments on catalytic performance were examined using standard SCR and non-selective NH3 oxidation kinetics. The zeolite framework integrity (crystallinity, porosity, coordination environments, Si-O-Al bonds, acidity) were characterized by XRD, N2 physisorption, solid state NMR, DRIFTS and NH3-TPD. A particular focus was given to changes in the local environments of Cu species during hydrothermal aging, examined using two-dimensional (2D) pulsed EPR. Finally, an attempt is made to elaborate the deactivation mechanisms that correlate the variation of NH3 storage sites (acid sites) and redox sites (Cu2+ sites) caused by low- and high-temperature hydrothermal treatments.
 Wang, J., Fan, D., Tie, Y., et al., J. Catal. 322:84-90, 2015
 Leistner, K., Olsson, L., Appl. Catal. B: Environ. 165: 192-199, 2015