In Situ/Operando Spectroscopic Studies on the NH3–SCR Mechanism over Fe–Zeolites

Reduction/oxidation half-cycles of the selective catalytic reduction of NO with NH3 (NH3–SCR) over Fe-exchanged mordenite (MOR) zeolites at 300 °C were investigated by in situ/operando spectroscopy (infrared, UV–vis, and Fe K-edge X-ray absorption near edge structure) and density functional theory (...

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Bibliographic Details
Published in:ACS catalysis 2022-08, Vol.12 (16), p.9983-9993
Main Authors: Yasumura, Shunsaku, Qian, Yucheng, Kato, Taisetsu, Mine, Shinya, Toyao, Takashi, Maeno, Zen, Shimizu, Ken-ichi
Format: Article
Language:English
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Summary:Reduction/oxidation half-cycles of the selective catalytic reduction of NO with NH3 (NH3–SCR) over Fe-exchanged mordenite (MOR) zeolites at 300 °C were investigated by in situ/operando spectroscopy (infrared, UV–vis, and Fe K-edge X-ray absorption near edge structure) and density functional theory (DFT) calculation. The reduction of Fe3+ into Fe2+ and the simultaneous formation of N2 and H2O in the reduction half-cycle (under NO + NH3) were demonstrated by different spectroscopic results. In the subsequent oxidation half-cycle (under O2 or NO + O2), Fe2+ was reoxidized into Fe3+. The reduction half-cycle comprises several elementary steps. Reduction of Fe3+–OH by NO producing Fe2+ and NO+ species was observed at low temperatures (
ISSN:2155-5435
2155-5435
DOI:10.1021/acscatal.2c02904