Assessing the Influence of Zeolite Composition on Oxygen-Bridged Diamino Dicopper(II) Complexes in Cu-CHA DeNO x Catalysts by Machine Learning-Assisted X-ray Absorption Spectroscopy
| Autor: | Andrea Martini, Chiara Negri, Luca Bugarin, Gabriele Deplano, Reza K. Abasabadi, Kirill A. Lomachenko, Ton V. W. Janssens, Silvia Bordiga, Gloria Berlier, Elisa Borfecchia |
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| Jazyk: | angličtina |
| Předmět: |
deNOx catalysis
Machine Learning-assisted EXAFS fitting Cu-Chabazite Catalysts Cu-Chabazite Selective Catalytic Reduction deNOx catalysis X-ray Absorption Spectroscopy EXAFS Wavelet Transform Machine Learning-assisted EXAFS fitting EXAFS Wavelet Transform X-ray Absorption Spectroscopy Oxidation Zeolites Selective Catalytic Reduction General Materials Science Redox reactions Physical and Theoretical Chemistry Extended X-ray absorption fine structure |
| Zdroj: | The Journal of Physical Chemistry Letters. 13(26):6164-6170 |
| ISSN: | 1948-7185 |
| DOI: | 10.1021/acs.jpclett.2c01107 |
| Popis: | Cu-exchanged chabazite is the catalyst of choice for NOx abatement in diesel vehicles aftertreatment systems via ammonia-assisted selective catalytic reduction (NH3− SCR). Herein, we exploit in situ X-ray absorption spectroscopy powered by wavelet transform analysis and machine learning-assisted fitting to assess the impact of the zeolite composition on NH3-mobilized Cu-complexes formed during the reduction and oxidation half-cycles in NH3− SCR at 200 °C. Comparatively analyzing well-characterized Cu-CHA catalysts, we show that the Si/Al ratio of the zeolite host affects the structure of mobile dicopper(II) complexes formed during the oxidation of the [CuI (NH3)2] + complexes by O2. Al-rich zeolites promote a planar coordination motif with longer Cu−Cu interatomic distances, while at higher Si/Al values, a bent motif with shorter internuclear separations is also observed. This is paralleled by a more efficient oxidation at a given volumetric Cu density at lower Si/Al, beneficial for the NOx conversion under NH3−SCR conditions at 200 °C. |
| Databáze: | OpenAIRE |
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