A Comparative Study between Real-world and Accelerated Lab Aging of Cu/SSZ-13 SCR Catalysts
Feng Gao, PNNL
Copper-exchanged chabazite catalyst Cu/SSZ-13 has been commercialized as a SCR catalyst for diesel engine exhaust deNOx for more than a decade. During this period, hydrothermal aging and sulfur poisoning have been identified as two main causes for catalyst degradation . With the implementation of ever stringent emission regulations and extended warranties for medium- and heavy-duty diesel-powered automobiles in the upcoming decade, it is important to continue our efforts exploring Cu/SSZ-13 aging mechanisms. Durability of Cu/SSZ-13 catalysts is traditionally evaluated by the so-called “accelerated lab aging” protocols developed to mimic real-world aging . Recent investigations at Cummins revealed, however, that real-world aging shows characteristics very different from aging based on current accelerated lab aging protocols. In order to develop accelerated aging methods that better mimic real-world aging, and to provide accurate predictive aging and performance models, PNNL and Cummins initiated a 3-year collaboration in 2020, investigating gaps between real-world and accelerated lab aging, and key causes for such gaps.
In this presentation, a wide array of catalyst characterization methods, including powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), solid-state nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), NH3 and NOx temperature-programmed desorption (TPD), and H2 temperature-programmed reduction (TPR) are used to comprehend key differences between real-world and lab aged catalysts.
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