Synthesis of multiwall carbon nanotubes/TiO2 nanotube composites with enhanced photocatalytic decomposition efficiency

Abstract Multiwall carbon nanotubes (MWCNT)-loaded TiO 2 nanotube (TNT) composites were synthesized by hydrothermal method. Scanning electron microscopy and transmission electron microscopy revealed the tubular morphology of the prepared TNT and MWCNT/TNT composites, which was further confirmed by the increase in their surface area. The MWCNT/TNT photocatalysts show high photocatalytic decomposition efficiency (PDE) for the degradation of rhodamine 6G (RhB-6G) dye, with excellent stability and reusability. Among the MWCNT/TNT composites, 10% loading of MWCNT results in a significantly higher PDE (89%) as compared with that of bare TNT (78%), Degussa P-25 TiO 2 (P25, 60%), and TiO 2 nanoparticles (56%). The enhanced PDE of MWCNT/TNT composites is due to the ability of the MWCNTs to promote the electron transfer process and reduce the electron-hole pair recombination rate, as also confirmed by photoluminescence measurements. Moreover, chemical oxygen demand (COD) and total organic carbon (TOC) analyses were performed to verify the RhB-6G dye degradation. Tubular morphology, enriched adsorption, synergic effect, and efficient separation of photogenerated electron-hole pairs account for the enhanced PDE of MWCNT/TNT composites in the decomposition of RhB-6G dye under the current experimental conditions.