The sulfonated (SO₃H-functionalized) carbon nanomaterials were obtained by direct sulfonation of the initial carbon nanofibers and nanotubes. Concentrated sulfuric acid, oleum (20% SO₃) and sulfonating mixtures containing 5 wt% MSO₄/H₂SO₄ (98%; M = VO²⁺, Cu²⁺, etc.) were used as a sulfating agents. It was shown that the use of MSO₄/H₂SO₄ sulfonating mixtures allows achieving the efficiency of the sulfonation comparable with the case of oleum. Thus, I the case of the most effective sulfonating mixtures containing such ions as VO²⁺, Cu²⁺, Fe³⁺, the values of the sulfur content were 1.2, 1.1 and 1.15 wt%, respectively. The optimal temperature of the sulfonation process was found to be in a range of 180-200 °C. All this provides a high acidity of the obtained materials along with maintaining the textural parameters (specific surface area of ∼100 and ∼300 m²/g for CNF and CNT, respectively). The structural changes of the materials taking place during the sulfonation process were studied by means of low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy, Raman spectroscopy, high resolution transmission electron microscopy, and both the titrimetric and elemental analyses. According to the data obtained, high efficiency of the sulfonating mixtures is stipulated by the process of oxidative destruction of the surface layer of the carbon material that leads to an increase of its defectiveness thus enhancing the sulfonation efficiency.

通过直接磺化初始碳纳米纤维和纳米管获得了磺化（SO ₃ H-官能化）的碳纳米材料。使用浓硫酸，发烟硫酸（20％SO ₃）和含有5 wt％MSO ₄ / H ₂ SO ₄（98％； M = VO 2 ⁺，Cu ²⁺等）的磺化混合物。已经表明，使用MSO ₄ / H ₂ SO ₄磺化混合物可以实现与发烟硫酸的情况相当的磺化效率。因此，在最有效的磺化混合物中，含有VO 2 ⁺，Cu ²⁺等离子，Fe ³⁺，硫含量分别为1.2、1.1和1.15wt％。发现磺化过程的最佳温度为180-200℃。所有这些都为所得材料提供了高酸度，并保持了质地参数（比表面积约为100和300 m ²/ g分别表示CNF和CNT）。通过低温氮吸附，X射线光电子能谱，拉曼光谱，高分辨率透射电子显微镜以及滴定和元素分析，研究了磺化过程中材料的结构变化。根据获得的数据，通过碳材料的表面层的氧化破坏的过程规定了磺化混合物的高效率，这导致碳材料的缺陷增加，从而提高了磺化效率。