Publication

Abstract : The surface properties of nanostructures play a vital role in defining the electrical and optical properties of nanomaterials needed for various applications. In this study, the TiCl 4 surface treatment approach was used to enhance the performance of TiO 2 nanotubes (T-NTs) based electrochemical sensors. The TiCl 4 treated TiO 2 nanotubes and pristine TiO 2 nanotubes were deposited with a glucose-sensing mediator (Cu 2 O nanoparticles (NPs)), and a systematic comparison of their performances using cyclic voltammetry (I-V) curves, Nyquist plot, Mott-Schottky plot, chronoamperometry (I-T) curves, and sensitivity curves are presented. The TiCl 4 treated sensors demonstrated 2 times higher sensitivity of 0.4 mA mM −1 cm −2 and 2.5 times lower limit of detection of 80μM , whereas the untreated nanotubes-based sensors had lesser sensitivity of 0.19 mA mM −1 cm −2 and a higher limit of detection of 200μM . Further, the treated substrates exhibited a higher donor charge density of 8.79×10 21 cm −3 in comparison to plain T-NTs ( 6.5×10 21 cm −3 ). The enhanced electrocatalytic performance of the surface-treated sensor was due to the formation of an additional TiO 2 layer over the surface of nanotubes which reduced the surface defects and introduced Ti 3+ ion in the nanotubes. This resulted in improved electronic contacts of T-NTs with the Cu 2 O NPs, increasing donor charge density, reduced band-gap, and yielded a three-fold enhancement in electrical conductivity, thereby increased the overall electrochemical sensing performance. Thus, the strategy of TiCl 4 surface modification on TiO 2 nanotube arrays is effective in enhancing the performance of T-NTs based electrochemical sensors.