This work presents a fast and versatile method to prepare carbon fibers from lignin. It involves the production of submicron-sized phosphorus-functionalized lignin fibers in only one step by electrospinning of lignin/H₃PO₄ solutions. The phosphorus functionalities enable shortening of the conventional stabilization process from more than 90 h to only 2 h thus avoiding fiber fusion or even stabilizing the lignin fibers in an inert atmosphere. The incorporation of H₃PO₄ into the initial lignin solution produces more oxidized spun lignin fibers, due to the reaction of phosphoric acid with the dissolved lignin, generating phosphate (and/or polyphosphate) esters throughout the structure of lignin fibers. These phosphate groups seem to be responsible for the production of cross-linking reactions during the stabilization step that are, in this case, very active and effective in increasing the glass transition temperature of the lignin fibers, reducing the time needed for the stabilization step and improving this process. Moreover, they promote the chemical activation of lignin fibers and greatly increase their oxidation resistance, avoiding their complete combustion during carbonization under a low concentration of O₂ at temperatures as high as 900 °C. The resulting carbon fibers gather different interesting properties, such as sub-micron diameters (≤1 μm), large surface area (≈2000 m² g⁻¹), relatively high performance in relation to their mechanical properties for functional applications and a rich variety of uniformly distributed O and P surface functionalities, which make them very attractive for heterogeneous catalysis, adsorption and electrochemical applications.

中文翻译：

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通过电纺丝木质素溶液快速制备高纳米孔亚微米直径碳纤维的磷官能化

这项工作提出了一种快速，通用的从木质素制备碳纤维的方法。它涉及通过电纺丝木质素/ H ₃ PO ₄溶液仅一步来生产亚微米尺寸的磷官能化木质素纤维。磷官能团能够将常规稳定过程从90多个小时缩短到仅2个小时，从而避免了纤维融合，甚至避免了在惰性气氛中稳定木质素纤维。H ₃ PO ₄的掺入由于磷酸与溶解的木质素的反应，在最初的木质素溶液中生成更多的氧化的纺丝木质素纤维，从而在整个木质素纤维的结构中生成磷酸酯（和/或聚磷酸酯）。这些磷酸酯基团似乎负责稳定步骤中的交联反应的产生，在这种情况下，这些交联反应非常活跃且有效地提高了木质素纤维的玻璃化转变温度，减少了稳定步骤所需的时间，并且改善这个过程。此外，它们促进木质素纤维的化学活化并大大提高其抗氧化性，从而避免了在低浓度O ₂碳化过程中木质素的完全燃烧。在高达900°C的温度下。所得的碳纤维具有不同的有趣特性，例如亚微米直径（≤1μm），大表面积（≈2000m ² g ^-1），相对于功能性应用的机械性能而言相对较高的性能以及丰富的品种具有均匀分布的O和P表面功能，这使其对于非均相催化，吸附和电化学应用非常有吸引力。