Abstract Heating free-base phthalocyanine (H2Pc) at around 450 °C under static vacuum results in the formation of a nonvolatile carbonaceous material through oxidative pyrolysis. We used a number of instrumental techniques to characterize its morphology and chemical composition. According to electron microscopy observations, the dominating morphology is fibrous. The estimated length of individual fibers, which appear as rather homogeneous and continuous structures, is several micrometers, with diameters of roughly 200 nm. According to elemental analysis estimates, the per cent contribution of carbon remains approximately the same as in pristine H2Pc, but about 5.4 at% of nitrogen is substituted by oxygen. Spectroscopic measurements suggest that the oxygen is incorporated into nanofiber structure in the form of different functionalities containing C O and C–OH bonds. Raman spectroscopy revealed an approximately equal contribution due to sp3 and sp2-hybridized carbon atoms, which would made one to expect that the thermal stability of nanofibers must be similar to that of defect-containing nanotubes, graphene oxide and nanodiamond. Nevertheless, according to thermogravimetric curves obtained, nanofibers are at least as thermally stable as graphene and defect-free nanotubes. Density functional theory calculations were employed to suggest possible initial steps of H2Pc oxidative pyrolysis leading to the formation of nanofibers.

中文翻译：

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来自游离碱酞菁热解的 N 掺杂碳纳米纤维

摘要 在静态真空下在 450 °C 左右加热游离碱酞菁 (H2Pc) 会导致通过氧化热解形成非挥发性碳质材料。我们使用了许多仪器技术来表征其形态和化学成分。根据电子显微镜观察，主要形态是纤维状。单根纤维的估计长度为几微米，直径约为 200 纳米，看起来是相当均匀和连续的结构。根据元素分析估计，碳的百分比贡献与原始 H2Pc 大致相同，但约 5.4 at% 的氮被氧取代。光谱测量表明，氧以包含 CO 和 C-OH 键的不同官能团的形式结合到纳米纤维结构中。拉曼光谱揭示了 sp3 和 sp2 杂化碳原子的贡献大致相等，这使人们预期纳米纤维的热稳定性必须与含缺陷的纳米管、氧化石墨烯和纳米金刚石的热稳定性相似。然而，根据获得的热重曲线，纳米纤维至少与石墨烯和无缺陷纳米管一样具有热稳定性。密度泛函理论计算被用来提出导致纳米纤维形成的 H2Pc 氧化热解的可能初始步骤。这使人们期望纳米纤维的热稳定性必须与含缺陷的纳米管、氧化石墨烯和纳米金刚石的热稳定性相似。然而，根据获得的热重曲线，纳米纤维至少与石墨烯和无缺陷纳米管一样具有热稳定性。密度泛函理论计算被用来提出导致纳米纤维形成的 H2Pc 氧化热解的可能初始步骤。这使人们期望纳米纤维的热稳定性必须与含缺陷的纳米管、氧化石墨烯和纳米金刚石的热稳定性相似。然而，根据获得的热重曲线，纳米纤维至少与石墨烯和无缺陷纳米管一样具有热稳定性。密度泛函理论计算被用来提出导致纳米纤维形成的 H2Pc 氧化热解的可能初始步骤。