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- Mesilov, Vitaly V., et al.
(författare)
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Differences in oxidation-reduction kinetics and mobility of Cu species in fresh and SO2-poisoned Cu-SSZ-13 catalysts
- 2021
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Ingår i: Applied Catalysis B. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 284
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Tidskriftsartikel (refereegranskat)abstract
- Fresh and SO2-poisoned Cu-SSZ-13 selective catalytic reduction (SCR) catalysts were studied using near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) in the presence of NH3, O2, and NO, as well as by in situ X-ray absorption spectroscopy (XAS) using H2, He, and CO. In contrast to the fresh catalyst, inhibited reduction of Cu-species and the absence of Cu-metal nanoparticles was found in the SO2-poisoned catalyst during heating/cooling in H2 and CO. High structural disorder and differences in the formation of Cu-carbonyl species were seen for the SO2-poisoned catalyst compared to the fresh catalyst. Suppressed oxidation-reduction and low mobility of Cu-species during exposure to NH3-SCR-related gases were observed in the SO2-poisoned catalyst, unlike in the fresh catalyst. These observations help explain catalyst deactivation during the standard NH3-SCR reaction. The formation of Cu-metal nanoparticles in the fresh catalyst revealed another possible deactivation pathway for the SCR-catalyst in combined LNT-SCR systems during fuel-rich periods.
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