Stabilization is the most complicated and time-consuming step in the manufacture of carbon fibers (CFs), which is important to prepare CFs with high performance. Accelerated stabilization was successfully demonstrated under effective plasma irradiation-assisted modification (PIM) of mesophase pitch fibers (PFs). The results showed that the PIM treatment could obviously introduce more oxygen-containing groups into PFs, which was remarkably efficient in shortening the stabilization time of PFs with a faster stabilization heating rate, as well as in preparing the corresponding CFs with higher performance. The obtained graphitized fiber (GF-5) from the PF-5 under PIM treatment of 5 min presented a higher tensile strength of 2.21 GPa, a higher tensile modulus of 502 GPa, and a higher thermal conductivity of 920 W/m·K compared to other GFs. Therefore, the accelerated stabilization of PFs by PIM treatment is an efficient strategy for developing low-cost pitch-based CFs with high performance.

The boron carbide (B₄C) nanoparticles doping mesophase pitch (MP) was synthesized by the in-situ doping method with tetrahydrofuran solvent, and the corresponding MP−based carbon fibers (CFs) were successfully prepared through the melt−spinning, stabilization, carbonization and graphitization processes. The structural evolution and properties of boron−containing pitches and fibers in different processes were investigated for exploring the effect of B₄C on mechanical, electrical and thermal properties of CFs. The results showed that the B₄C was evenly dispersed in pitch fibers to provide active sites of oxygen, resulting in a homogeneous stabilization and ameliorating the split−ting microstructures of CFs. Moreover, the thermal conductivity of B1−MP−CF prepared with 1 wt.% B₄C increased to 1051 W/m•K, which was much higher than that of B0−MP−CF prepared without B₄C (659 W/m•K). While the tensile strength of B₄C−doped CFs was lower than that of pristine CFs. In addition, a linear relationship equation between the graphite microcrystallite parameter (I_D/I_G) calculated from Raman spectra and the thermal conductivity (λ) calculated according to the electrical resistivity was found, which was beneficial to understand the thermal properties of CFs. Therefore, the doping B₄C nanoparticles in MP did play a significant role in reducing the graphitization temperatures due to the boron catalytic graphitization but decreasing the mechanical properties due to the introduction of impurities.

The design of catalytic materials for NO_X removal by the selective catalytic reduction with NH₃ (NH₃-SCR) has been a focus of research in the field of waste gas treatment. In this work, pitch-based activated carbon fibers (ACFs) were impregnated with copper nitrate and cerium nitrate, and then the ACFs that were loaded with bimetallic nanoparticles (ACF@Cu/Ce) were obtained after the pyrolyzation and reduction were performed. Moreover, the ACF@Cu/Ce were furtherly treated through the chemical vapor deposition and NH₃ activation, through which the N-doped carbon nanofibers (N-CNFs) were grown on the surface of the ACFs. Thus, the catalytic material with a multi-dimensional metal nanoparticle distribution and nitrogen-rich network structure, namely the N-CNF/ACF@Cu/Ce, was constructed. In the NH₃-SCR reaction, the NO conversion of the N-CNF/ACF@Cu/Ce could be maintained at about 72~81% in a wide temperature window of 295~495 °C, which enabled the N-CNF/ACF@Cu/Ce to meet the requirements of the practical applications.