Characterization of deactivated Cu/ZSM-5 lean NO{sub x} reduction catalysts

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:214609

Yan, J Y; Lei, G D; Sachtler, W M.H.; Kung, H H ^[1]

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1. Northwestern Univ., Evanston, IL (United States)

Temperature programmed reduction (TPR), FT-IR of adsorbed CO and electron paramagnetic resonance (EPR) were used to investigate the state of copper in fresh and deactivated Cu/ZSM-5 lean NO{sub x} reduction catalysts. In fresh calcined Cu/ZSM-5, three types of copper were observed that possess different reduction kinetics. They are assigned to isolated Cu{sup 2+} (major), [Cu-O-Cu]{sup 2+} (minor) and CuO (minor). The total amount of the first two ionic copper species after lean NO{sub x} reduction treatment decreased with increasing severity of deactivation. TPR results showed a new reduction feature in the deactivated Cu/ZSM-5 catalysts. These, together with results from the EPR studies, suggested that part of the original active Cu{sup 2+} ions in the 5-coordinated square pyramid environment, were changed to inactive Cu{sup 2+} in a 4-coordinated square planar environment. This change was irreversible, probably due to the structural change of the zeolite (i.e. dealumination).

• OSTI ID: 214609
• Report Number(s): CONF-950801--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
02 PETROLEUM
40 CHEMISTRY
54 ENVIRONMENTAL SCIENCES
CATALYSTS
CATALYTIC EFFECTS
COMBUSTION PRODUCTS
COPPER
DEACTIVATION
FOSSIL FUELS
HYDROCARBONS
NITROGEN OXIDES
POLLUTANTS
REDUCTION
ZEOLITES