## 2 Results and Discussion  
Figure 1a provides a diagram of the preparation route for CF materials with varying DVB contents using a classical pyrolysis process catalyzed by FeAC. Figure 1b-e display the surface morphology of the CF series materials characterized by SEM. It was observed that as the DVB content increased, the ceramic matrix transitioned from a dense structure to a loose, porous structure, with more tubular structures, believed to be CNTs, gradually appearing within the ceramic matrix. Subsequently, we further observed the microscopic structure of the materials using TEM. As illustrated in Figure 1f, CF-75 contained numerous tubular structures interwoven between particles. The lattice fringes of graphitized carbon were clearly observed in the HRTEM image in Figure 1g, confirming the presence of CNTs in the material. Additionally, a small number of metal particles inside the material were observed, as shown in Figure 1h,i, which were connected to the CNTs. The lattice spacing of these particles was 0.21 nm, corresponding to the (110) plane of \(\alpha\)-Fe. This suggests that the growth mechanism of CNTs within the material could be explained as follows: Throughout the pyrolytic conversion of the SiOC precursor, a large number of hydrocarbon and carbon-oxygen compound gas molecules serve as carbon sources, preferentially deposited on the surface of metallic iron. These molecules dissolve and polymerize on the metal surface, further growing outward in a crystalline form, ultimately forming one-dimensional CNTs [30; 31; 32; 33]. Figure 1: (**a**) Preparation process schematic of the CF series samples; morphological characterization of the CF series samples: (**b**) CF-25, (**c**) CF-50, (**d**) CF-75, (**e**) CF-10, (**f**-i**) TEM and HRTEM images of CF-75. To study the structure of the synthesized precursors, chemical bond changes in four different precursors were analyzed using FT-IR. As illustrated in Figure 2a, all samples exhibited the Si-O-Si bond at 1200 cm\({}^{-1}\), which is characteristic of the SiOC precursor backbone. With the increase in DVB content, the peaks of C=C (1600 cm\({}^{-1}\) and 1450 cm\({}^{-1}\)) and Si-CH\({}_{2}\)-CH\({}_{2}\) (2920 cm\({}^{-1}\)) significantly increased, while the peak intensity of Si-H (2160 cm\({}^{-1}\)) gradually decreased. This decrease was attributed to the silicon-hydrogen addition reaction between polymethylhydrosiloxane (PMHS) and DVB, and the increase in vinyl and phenyl content helped retain more free carbon during the pyrolysis process. Furthermore, with the introduction of FeAC, absorption peaks corresponding to C=O (1605 cm\({}^{-1}\)), Si-O-Fe (930 cm\({}^{-1}\)), and Fe-O (667 cm\({}^{-1}\)) appeared in the precursor. This appearance was due to the reaction of FeAC with PMHS through condensation and addition, which is consistent with literature reports on the chemical reactions forming Si-O-M (M=Fe, Co, Ni) bonds between acetylacetonate metal compounds and Si-H [34]. In order to comprehend the thermal behavior of precursors during the ceramization process, TGA was utilized to study the mass changes of iron-containing precursors with different amounts of DVB during pyrolysis, as depicted in Figure 2b. It was observed that the precursor exhibited a small thermal weight loss starting at 200 \({}^{\circ}\)C, which could be attributed to the decomposition of the FeAC ligands. The significant weight reduction happened in the 400-800 \({}^{\circ}\)C temperature span and was attributed to the breaking and rearrangement of various chemical bonds in the precursor (Si-H, Si-C, C-H) as the pyrolysis temperature increased. This was due to the emission of numerous small molecular gases, including CH\({}_{4}\), CO, H\({}_{2}\), and C\({}_{2}\)H\({}_{6}\), during the ceramization process, which facilitated the conversion of organic substances into inorganic ones [35]. From the spectra, it was observed that with increasing DVB content, the mass loss of the samples showed an upward trend.