Effect of various structure directing agents (SDAs) on low-temperature deactivation of Cu/SAPO-34 during NH3-SCR reaction
Artikel i vetenskaplig tidskrift, 2018

Cu/SAPO-34 and Cu/SSZ-13 having chabazite structure (CHA) have attracted significant attention because of their high activity and N2selectivity during SCR reaction as well as superior resistance to hydrocarbon poisoning. Cu/SAPO-34 has shown better hydrothermal durability than Cu/SSZ-13 at high temperature. However, we have observed earlier that Cu/SAPO-34 prepared using morpholine as a structure directing agent (SDA) deteriorated under water exposure at low temperature, where the NOxconversion activity decreased from 87% to 6% after 9 h of low temperature exposure. In this study, Cu/SAPO-34 catalysts prepared using three different SDAs, i.e., morpholine (MO), triethylamine (TEA), and tetraethylammonium hydroxide (TEAOH), were prepared by the incipient wetness impregnation (IWI) method. A commercially purchased SAPO-34 (SAPO-34(ACS)) was also used for comparison purposes. After low temperature water deactivation, Cu/SAPO-34(TEA) and (TEAOH) mostly recovered their activities while Cu/SAPO-34(MO) and (ACS) only regained part of their activities after regeneration tests under a series of experimental conditions for the NH3-SCR reaction. Solid-state MAS NMR was employed to study the impact of SDAs on the coordination of Al, P, and Si in the SAPO-34 supports and Cu/SAPO-34 catalysts. CO-DRIFTS, NO-DRIFTS, and H2-TPR employed in this study collectively propose the presence of two different Cu locations in Cu/SAPO-34(MO, TEA, TEAOH, and ACS). It is suggested that the concentrations of Cu in two distinct locations within Cu/SAPO-34 catalysts characterized by CO-DRIFTS, NO-DRIFTS, and H2-TPR studies are significantly influenced by the choice of SDA, which will be important for understanding the deactivation mechanism of Cu/SAPO-34 catalysts during low temperature NH3-SCR reaction.

Författare

Jung Won Woo

Chalmers, Kemi och kemiteknik, Kemiteknik, Kemisk reaktionsteknik

Kirsten Leistner

Chalmers, Kemi och kemiteknik, Kemiteknik, Kemisk apparatteknik

Diana Bernin

Chalmers, Kemi och kemiteknik, Kemiteknik, Kemisk apparatteknik

Homayoun Ahari

Fiat Chrysler Automobiles

Mark Shost

Fiat Chrysler Automobiles

Michael Zammit

Fiat Chrysler Automobiles

Louise Olsson

Chalmers, Kemi och kemiteknik, Kemiteknik

Catalysis Science and Technology

2044-4753 (ISSN) 2044-4761 (eISSN)

Vol. 8 3090-3106

Ämneskategorier

Oorganisk kemi

Annan kemiteknik

Organisk kemi

DOI

10.1039/c8cy00147b