Assessing impact of real-world aging on Cu-redox half cycles of a Cu-SSZ-13 SCR catalyst via transient response measurements and kinetic modeling
Deka, Dhruba J. 1Daya, Rohil 2Ladshaw, Austin 1Trandal, Dylan 2Joshi, Saurabh Y. 2Partridge, William P.1
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作者信息
1. Oak Ridge Natl Lab
2. Cummins Inc
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Abstract
The SCR reaction on Cu-SSZ-13 is a redox process consisting of a reduction half-cycle (RHC) and an oxidation half-cycle (OHC). Despite extensive efforts to understand hydrothermal aging and sulfur poisoning, the impact of real-world aging on the SCR activity of Cu-SSZ-13 has not been reported. This work employs a transient response methodology consisting of experiments and kinetic models to investigate the SCR redox cycles at intra-catalyst locations of commercial Cu-SSZ-13 monolith catalysts in their degreened and real-world aged states, in the temperature range of 200-450 degrees C. Moreover, H2-TPR, NH3-TPD, SO2-TPD, ICP-OES and solid-state NMR were performed to investigate the catalyst properties. Sulfur aging and dealumination caused by real-world exposure decreased the reducible Cu density and SCR performance. Real-world aging was found to selectively slow OHC more than RHC, mainly due to lower mobility of the Cu ions coordinated to sulfur-related species leading to decreased formation of Cu-dimers necessary for OHC.
NSTL
Elsevier