Low Temperature Deactivation of Cu/SAPO-34 Catalysts Synthesized Using Different SDAs During NH3-SCR Reaction

Jungwon  Woo, Chalmers University of Technology

It is well known that some SAPO-34 materials are sensitive to humidity at ambient condition after removal of their structure directing agents (SDAs). Briend et al. [1] proposed that the choice of SDAs is strongly related with the stability of SAPO-34 framework. In addition, our earlier study also showed that Cu/SAPO-34 using morpholine (MO) as SDA rapidly loss its activity when they were exposed to water vapor at low temperature [2]. The deactivation of Cu/SAPO-34 catalysts is a challenge for auto industry and several research groups have studied Cu/SAPO-34 catalysts in NH3-SCR applications to understand its failure mechanism [3-4]. In a recent study, we found that species, location, and concentration of Cu in SAPO-34 resulting from using different SDAs, is closely related to their unique catalytic behavior in terms of activity, stability and regeneration in NH3-SCR application [5]. However, different deactivation mechanisms of Cu/SAPO-34 catalysts exposed to water vapor at low temperature, prepared by different SDAs, during NH3-SCR reaction is not yet fully understood.

Henceforth, in this study, we investigated the deactivation mechanisms of Cu/SAPO-34 catalysts, caused by water vapor at low temperature, prepared using three different SDAs, morpholine (MO), triethylamine (TEA), and tetraethylammonium hydroxide (TEAOH), during NH3-SCR reaction through systematic characterization of the deactivated catalysts using various characterization techniques such as: XRD, BET, Solid state NMR, CO-DRIFTS, NO-DRIFTS, H2-TPR.

References
[1] M. Briend, R. Vomscheid et al., J. Phys. Chem., 99 (1995) 8270.
[2] K. Leistner, L. Olsson, Appl. Catal., B: Environmental, 165 (2015) 192.
[3] J. Wang, D. Fan et al., J. Catal., 322 (2015) 84.
[4] X. Xiang, P. Wu, et al., Chinese J. Catal., 38 (2017) 918.
[5] J. Woo, K. Leistner et al., submitted to Catal. Sci. Technol (2018).