Characterization of atomic structure of single Pt atoms on N-doped graphene
| Project/Area Number |
19K15439
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 29020:Thin film/surface and interfacial physical properties-related
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| Research Institution | Hokkaido University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2020: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2019: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Keywords | 金属単原子 / 単原子触媒 / TEM / グラフェン / 単原子スパッタリング / TEM、STEM / 電子顕微鏡 |
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| Outline of Research at the Start |
本研究課題では単原子触媒材料として期待されるPt単原子分散体の原子分解能、3次元でのイメージングを行う。申請者独自のPt単原子分散手法を用いたサンプルに対して収差補正透過型電子顕微鏡による原子分解能イメージング、原子分解能EELS解析を行い窒素ドープグラフェンにアンカーされたPt単原子の3次元原子配置を示すことによって、Pt単原子の安定化に対する窒素の作用を明らかにする。
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| Outline of Final Research Achievements |
Single-atom catalysts are attracting attention due to their superior catalytic activity and cost. Nitrogen (N) enhances the stability of single platinum (Pt) atoms on graphene because Pt atoms dispersed by plasma sputtering in an N2 atmosphere are less likely to aggregate. However, the atomic structure of Pt and N on graphene has not been clarified. Here, we experimentally revealed the atomic arrangement of Pt, N, and carbon (C) by scanning transmission electron microscopy and electron energy loss spectroscopy. Pt and N atoms were adsorbed near the step edge of nanographene stacked on single-layer pristine graphene, rather than on the terrace. DFT calculation using the experimental structure confirmed that the single Pt atom has high stability because N strengthens the bond between Pt and C at the step edge. In addition to a large decrease in the population of Pt 5dxy-orbital, an increase in the population of 5dyz-orbital was observed.
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| Academic Significance and Societal Importance of the Research Achievements |
単原子触媒の化学反応活性の高さは吸着構造に大きく影響する。これまでにグラフェン上のPt単原子の多くがグラフェンのステップエッジに多く吸着し、ステップエッジでの原子配置を明らかにしたが、より単原子が安定に存在する窒素ドープグラフェンの原子配置を明らかにした例はこれまでなかった。本研究では収差補正走査透過型顕微鏡（STEM）を用いた電子エネルギー損失分光(EELS)マッピングによって窒素ドープグラフェン上のPt単原子の原子配置を始めて明らかにし、理論計算によって吸着構造の電子状態を明らかにした。
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Report
(3 results)
Research Products
(7 results)
