Recent Developments in Titania–Carbon Nanotube Nanohybrids: Towards Enhanced Photocatalytic Efficiency

The water treatment industry is facing unprecedented challenges with emerging contaminants of concerns especially those emanating from textile industries. These contaminants overwhelm the existing water treatment infrastructure thus necessitating the exploration of emerging technologies to supplement the existing water treatment technologies. Advanced oxidation processes (AOPs) are an emerging technology that has demonstrated potential in addressing shortcomings of existing water technologies. This is owing to the ability of AOPs to indiscriminately break down organic pollutants into smaller molecules with a low environmental footprint with the agency of light. Among the AOPs, semiconductor photocatalysts and the nanohybrids of the semiconductors with carbonaceous materials, have been demonstrated to be leading candidates owing to their ability to break down the organics in water in shorter contact times. Nanostructured hybrids consisting of titania (TiO2) supported on carbon nanotubes (CNTs) are a promising avenue towards the enhancement of visible light and eco-friendly photocatalytic activity of TiO2. This is because of the ability of these photocatalytic nanohybrids to absorb light ranging from the ultraviolet (UV) to the near infrared region (NIR) and their typically large active surface area. They have also found use in other vital areas such as energy production and storage, electrical circuitry, health, environmental remediation and monitoring. However, with such prospects, they have not been used in applications past bench-top tests. This is because the milestones reached in the development of these unique nanohybrids is scattered research papers and hence the understanding of the nanohybrids by its end-consumers remains scanty. This chapter seeks to trace the development of these nanohybrids and consolidate the latest trends in their synthesis, modification, characterization, and application for enhanced photocatalytic activity. Key characterization techniques for these nanohybrids, the relevance of each technique as applied in selected examples are also discussed. A wide range of applications and their results are covered for a fair assessment of the performance of these nanohybrids under various conditions. Lastly opportunities, limitations and future perspectives presented by these unique nanohybrids are also explored as drivers towards the realization of their full potential.