D. Sibanda, P. E. Mallon
This study investigates the synthesis, characterisation, and photocatalytic performance of nitrogen-doped porous carbon/TiO 2 –CdS composite fibres using high-molecular-weight poly (acrylonitrile)- block -poly (butyl acrylate) (PAN- b -PBA) block copolymers synthesised via atom transfer radical polymerisation (ATRP). Block copolymer templates were utilised to control the nanostructure and porosity of the resulting carbon-ceramic hybrid fibres, enhancing their photocatalytic efficiency. Photocatalytic degradation experiments using methylene blue (MB) as a model pollutant revealed that the carbon/TiO 2 –CdS composite fibres showed superior degradation rates compared with those of bare TiO 2 nanoparticles and nitrogen-doped carbon fibre controls. The hybrid structure facilitated enhanced charge separation and reduced electron-hole recombination, leading to improved photocatalytic activity under UV/Visible-light irradiation. The MB degradation efficiency decreased with increasing pollutant concentration, with a maximum removal of 57% at 5 mg/L MB concentration. Kinetic analysis indicated that the lowest MB concentration yielded the highest reaction rate (k = 0.00760 min −1 ). Moreover, cycle experiments showed that the hybrid fibres maintained significant catalytic stability over multiple reuse cycles, with a gradual decline in photocatalytic efficiency from 57% to 32% after three cycles. Comparative analysis with other photocatalytic materials highlighted the advantages of the nitrogen-doped carbon/TiO 2 –CdS composite fibres in terms of stability, recyclability, and ease of recovery. Unlike slurry-based TiO 2 –CdS nanoparticles, which require complex separation methods, the fibrous composites could be easily retrieved from aqueous solutions, making them a cost-effective alternative for wastewater treatment applications.