Formation of Sublimable Nanographene Oxides by Reacting Coronene Films with Atomic Oxygen
Formation of Sublimable Nanographene Oxides by Reacting Coronene Films with Atomic Oxygen
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DOI：
10.1021/acs.jpcc.8b01655
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
J. Weippert;S. Ulas;Dmitry V. Strelnikov;A. Böttcher;M. Kappes
中科院分区：
文献类型：
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作者：
J. Weippert;S. Ulas;Dmitry V. Strelnikov;A. Böttcher;M. Kappes
我们研究了超高压条件下石墨上多层冠烯（C24H12）薄膜的氧化反应。采用低能簇离子束沉积法（LECBD, C24H12+, Ekin < 6 eV）生长冠烯薄膜，并在室温下将其暴露于近热原子氧束中氧化。在氧化的冕烯薄膜升华过程中记录的质谱显示了发射物质C24H12On （n≤7）的分布，我们将其称为冕烯环氧化物。根据离散傅立叶变换（DFT）计算得出，环型环氧化物主要形成，其稳定性高于芯型环氧化物。除了环氧化物，XPS还表明，其他的氧化官能团，如醚，也以相对较少的数量作为不可升华的物质形成。完整的冕烯氧化物热解吸的总产率可达沉积冕烯的7%，足够高，因此该过程可以作为单分散纳米级g的来源。
We have studied the oxidation of multilayer thin films of coronene (C24H12) on graphite under UHV conditions. Coronene films were grown by low-energy cluster ion beam deposition (LECBD, C24H12+, Ekin < 6 eV) and subsequently oxidized by exposing them to a beam of near-thermal atomic oxygen at room temperature. Mass spectra recorded during sublimation of the oxidized coronene films reveal a distribution of emitted species, C24H12On (n ≤ 7), which we assign as coronene epoxides. From the fragmentation pattern we infer that primarily rim epoxides are formed, which exhibit a higher stability than core epoxides according to DFT calculations. In addition to epoxides, XPS indicates that other oxidic functional groups, such as ethers, are also formed in smaller relative amounts as nonsublimable species. The overall yield for the thermal desorption of intact coronene oxides can be up to 7% of the deposited coronene, sufficiently high such that this procedure could be useful as a source of monodispersed nanoscale g...