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- L. Bergman, Susanna, et al.
(författare)
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Probing the Oxidation/Reduction Dynamics of Fresh and P-, Na-, and K-Contaminated Pt/Pd/Al2O3 Diesel Oxidation Catalysts by STEM, TPR, and in Situ XANES
- 2020
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Ingår i: The Journal of Physical Chemistry C. - Washington, D.C. : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 124:5, s. 2945-2952
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Tidskriftsartikel (refereegranskat)abstract
- This study examines the oxidation and reduction behavior of Pt/Pd/Al2O3 diesel oxidation catalysts at temperatures and gas compositions that model the conditions of the working diesel oxidation catalyst in a truck exhaust system. In situ measurements using Pt L3 X-ray edge absorption spectroscopy are coupled with temperature-programmed reduction (TPR) and scanning transmission electron microscopy measurements to characterize the catalyst. The fresh catalyst is compared with chemically aged catalysts, exposed to Na, K, and P contaminants. Phosphorus exhibits strong, spatially localized interactions with the Pt/Pd catalyst nanoparticles that are reflected in a strong shift to lower energy of the Pt L3 edge under CO oxidation conditions. The Na and K poisons are spread more uniformly throughout the catalyst washcoat and do not strongly affect the edge spectra or the TPR-determined catalyst reducibility.
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