Impact of ferrocene on the structure of diesel exhaust soot as probed with wide-angle X-ray scattering and C(1s) NEXAFS spectroscopy

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• 作者：Artur Braun ; Frank E. Huggins ; Kerry E. Kelly ; Bongjin S. Mun ; Steven N. Ehrlich and Gerald P. Huffman
• 关键词：Non-graphitic carbon ; Soot ; Catalyst ; X-ray scattering ; Microstructure
• 刊名：Carbon
• 出版年：2006
• 出版时间：November 2006
• 年：2006
• 卷：44
• 期：14
• 页码：2904-2911
• 全文大小：675 K

文摘

We report on the structure of a set of diesel exhaust samples that were obtained from reference diesel fuel and diesel fuel mixed with ferrocene. Characterization was carried out with X-ray absorption spectroscopy (C(1s) NEXAFS) and wide-angle X-ray scattering (WAXS). The reference diesel soot shows a pronounced graphite-like microstructure and molecular structure, with a strong (0 0 2) graphite Bragg reflex and a strong aromatic CC resonance at 285 eV. The mineral matter in the reference soot could be identified as Fe₂O₃ hematite. The soot specimen from the diesel mixed with ferrocene has an entirely different structure and lacks significantly in graphite-like characteristics. NEXAFS spectra of such soot barely show aromatics but pronounced contributions from aliphatic structures. WAXS patterns show almost no intensity at the Bragg (0 0 2) reflection of graphite, but a strong aliphatic γ-side band. The iron from the ferrocene transforms to Fe₂O₃ maghemite.