Effect of Nanotube Diameter on Photo-Electro-Chemical Properties of Carbon Quantum Dot Functionalized TiO2 Nanotubes (original) (raw)

We report the photo-electro-chemical properties of Carbon Quantum Dots (CQD) functionalised TiO 2 nanotube arrays (TNA). The TNA formed by electrochemical anodization of a Ti foil offer highly aligned, vertically oriented nanostructures suitable for photo-catalytic application. These nanostructures are functionalised with CQDs synthesized by the electrochemical etching of graphite and the resultant samples are characterized by high resolution transmission electron microscopy, photo-current and photon-charge conversion efficiency measurements, Mott-Schottky and impedance spectroscopy. The results indicate that the nanotubes with larger diameter can support a higher density of CQDs and hence shows better values for photo-current and light conversion efficiency. Furthermore, these samples offer a lower charge transfer resistance across the semiconductorelectrolyte interface. The CQD functionalised TiO 2 nanotubesarrays with suitable diameter can therefore be used for efficient hydrogen generation by water splitting under the illumination of solar radiation. Index Terms-TiO 2 , carbon quantum dot (CQD), photoelectro-chemical, clean energy.