Carbon fibers with infiltrated TiO2 nanocrystalline layers: photocatalytic performance

Abstract

This study examines the synergy of carbon fibers (CFs) and an infiltrated TiO₂ nanocrystalline layer for photocatalytic degradation of methylene blue (MB). The CFs@TiO₂ nanocomposite was developed using Vapour Phase Infiltration (VPI) of TiO₂ into polyacrylonitrile fibers with 5–160 infiltration cycles and subsequently carbonized at 900 °C. This integrated production method enables precise integration of TiO₂ and consistent coating over the fiber surface. SEM confirms the TiO₂ layer thickening from 15.7 ± 2.4 nm to 34.7 ± 3.4 nm as the cycles increase from 40 to 160, while EDX and EDXRF indicate a similar rise in TiO₂ content. XRD and Raman spectroscopy confirm the production of anatase TiO₂ for VPI 40 c and higher, attributed to size-induced crystallization. UV–Vis DRS demonstrates that the optical bandgap varies with the cycle number in accordance with the development of the TiO₂ layer. The outcomes of photocatalytic experiments under UV illumination indicate that the maximum degradation rate is achieved with the thickest coating. The CFs@TiO₂ demonstrate exceptional cycle stability. This study emphasizes the potential of VPI-derived CFs@TiO₂ as durable and effective photocatalysts.