The fabrication of CNTs/TiO2 photoanodes for sensitive determination of organic compounds

Abstract

Titanium dioxide (TiO2) and carbon nanotubes (CNTs) are the two most popular functional materials in recent years. In this study, CNTs/TiO2 composite and TiO2 photoanodes were fabricated by a dip-coating technique, followed by subsequent calcination. The resultant photoanodes were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), and UV–visible spectroscopy (UV–vis). The results suggest that the carbon nanotubes were successfully incorporated with the TiO2 nanoparticulates without damage and that the resultant TiO2 nanoparticles consisted of anatase and rutile. The CNTs/TiO2 photoanodes were capable of oxidizing various types of organic compounds (e.g. glucose, potassium hydrogen phthalate, and phenol) in aqueous solutions in a photoelectrochemical bulk cell. In comparison with the pure TiO2 photoanode, the sensitivity of the photoanode for the detection of organic compounds has been improved by 64%, while the background current was reduced by 80% due to the introduction of the CNTs. These advantages can be ascribed to the improved adsorptivity to organic compounds, increased absorption of UV light and enhanced electron transport at the CNTs/TiO2 photoanode due to the introduction of the CNTs.