Role of lattice oxygen and oxygen vacancy sites in platinum group metal catalysts supported on Sr3Fe2O7−δ for NO-selective reduction,Catalysis Science & Technology

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Role of lattice oxygen and oxygen vacancy sites in platinum group metal catalysts supported on Sr3Fe2O7−δ for NO-selective reduction
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2017-11-13 00:00:00 , DOI: 10.1039/c7cy01861d
Kosuke Beppu _{1,

2,

3,

4,

5} , Saburo Hosokawa _{1,

2,

3,

4,

5} , Hiroyuki Asakura _{1,

2,

3,

4,

5} , Kentaro Teramura _{1,

2,

3,

4,

5} , Tsunehiro Tanaka _{1,

2,

3,

4,

5}

Affiliation

This study demonstrates that NO-selective reduction with C₃H₆ and CO proceeds over platinum group metal (PGM; Pd, Rh, or Pt) catalysts supported on Sr₃Fe₂O_7−δ with a layered perovskite-type oxide. Among the examined catalysts, Pd-loaded Sr₃Fe₂O_7−δ having high oxygen storage capacity shows the highest catalytic activity at stoichiometric oxygen concentration because the Pd catalyst can release the lattice oxygen of Sr₃Fe₂O_7−δ at lower temperature compared to the Rh- or Pt-loaded catalyst. When the NO-selective reduction at 773 K is carried out at various oxygen concentrations, PGM/Sr₃Fe₂O_7−δ shows superior catalytic activity over a wide range of oxygen concentrations to PGM/Al₂O₃, which does not have oxygen storage capacity. The oxygen vacancy sites in Sr₃Fe₂O_7−δ, which are generated by the oxidation of C₃H₆ and CO over PGM/Sr₃Fe₂O_7−δ, are revealed to receive oxygen ions formed by NO reduction on the PGM species; as a result, the PGM species maintain their metal state and act as active sites for NO reduction. Namely, Sr₃Fe₂O_7−δ plays the role of an “oxygen buffer” in inhibiting the PGM-to-oxide transformation. Pt-loaded Sr₃Fe₂O_7−δ can utilize the oxygen vacancy sites more effectively for the catalytic reaction than the Pd and Rh catalysts. To the best of our knowledge, this is the first report on the effective application of perovskite materials with oxygen storage capacity as catalyst supports for NO-selective reduction. The study results are expected to provide valuable information for designing a novel catalyst based on oxygen storage materials.

中文翻译：

Sr ₃ Fe ₂ O ₇ − _δ负载的铂族金属催化剂中晶格氧和氧空位对NO选择性还原的作用

这项研究表明，用层状钙钛矿型氧化物负载在Sr ₃ Fe ₂ O _7-_δ上的铂族金属（PGM； Pd，Rh或Pt）催化剂上，用C ₃ H ₆和CO进行的NO选择性还原。在所研究的催化剂中，具有高储氧能力的负载Pd的Sr ₃ Fe ₂ O _7-_δ在化学计量的氧浓度下显示出最高的催化活性，因为Pd催化剂可以释放Sr ₃ Fe ₂ O _7-_δ的晶格氧。与负载Rh或Pt的催化剂相比，温度更低。当在773 k中的NO-选择性还原在不同的氧浓度，PGM被执行/ SR ₃的Fe ₂ ö _{7- δ}示出在宽范围内的氧浓度至PGM / Al的优良的催化活性₂ ö ₃，其不具有储氧量。Sr ₃ Fe ₂ O _{7- δ中}的氧空位是由PGM / Sr ₃ Fe ₂ O _7-_δ上的C ₃ H ₆和CO氧化产生的揭示了在PGM物种上接收到由于NO还原而形成的氧离子; 结果，PGM物种保持其金属态并充当NO还原的活性位点。即，Sr ₃ Fe ₂ O _{7- δ}在抑制PGM向氧化物的转变中起“氧缓冲剂”的作用。铂载Sr ₃ Fe ₂ O _{7− δ}与Pd和Rh催化剂相比，Pt可以更有效地利用氧空位来进行催化反应。据我们所知，这是关于有效应用具有储氧能力的钙钛矿材料作为NO选择性还原催化剂的第一份报告。预期该研究结果将为设计基于储氧材料的新型催化剂提供有价值的信息。

更新日期：2017-11-24

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