2020年2月
Dynamics of the Lattice Oxygen in a Ruddlesden-Popper-type Sr3Fe2O7-d Catalyst during NO Oxidation
ACS CATALYSIS
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- 巻
- 10
- 号
- 4
- 開始ページ
- 2528
- 終了ページ
- 2537
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1021/acscatal.9b03857
- 出版者・発行元
- AMER CHEMICAL SOC
In situ observation is a powerful and interesting technique for the characterization of functional materials in their working states. In this study, we used in situ dispersive X-ray absorption fine structure (DXAFS) measurements to observe the lattice oxygen dynamics in SrFeO3-delta and Sr3Fe2O7-delta during NO oxidation. The white-line intensities of Sr K-edge XAFS reflect the concentration of oxygen vacancies, and the lattice oxygen dynamics during NO oxidation are observed. Using a kinetics model, the rate-determining step (RDS) for NO oxidation was found to be an oxygen migration step. The activation energy obtained from the Arrhenius plots for Sr3Fe2O7-delta is much smaller than that obtained for SrFeO3-delta. Sr3Fe2O7-delta with a Ruddlesden-Popper-type layered perovskite can release oxygen with relatively small structural rearrangements. In contrast SrFeO3-delta requires a significant rearrangement of oxygen vacancies to form the brownmillerite phase and the transformation restricts the oxygen release rate. The oxygen storage profiles with O-2 also show that the RDS is the oxygen migration step, although the dissociative adsorption of O-2 suppresses oxygen storage at low temperatures. The lattice oxygen dynamics obtained from the DXAFS measurements, which cannot be obtained from steady-state kinetics experiments, reveal the importance of the perovskite structure for NO oxidation.
- リンク情報
- ID情報
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- DOI : 10.1021/acscatal.9b03857
- ISSN : 2155-5435
- Web of Science ID : WOS:000516887400014