Influence of laser and alkali treatment on an Ag/TiO₂ nanotube based dopamine sensor

Abstract

Herein, TiO2 nanotubes (T-NTs) arrays were subjected to two types of treatment followed by a simple metal deposition technique to significantly enhance the performances of T-NTs based electrochemical sensing of dopamine. The first type of treatment was done by soaking T-NTs in sodium hydroxide solution for an optimal time to enhance the conductivity and charge carrier density. The second type of treatment employed was laser irradiation, which induces crystallinity disorder and forms rutile TiO2, promoting active analyte adsorption sites. Afterward, silver (Ag) was electro-deposited on the T-NTs as a dopamine sensing catalyst to form T-NTs/Ag nanohybrids. The dual-treated T-NTs based sensor showed 3-fold enhancement in sensitivity (from 8.2 μA mM−1 cm−2 to 32 μA mM−1 cm−2), reduced charge transfer resistance (from 38 × 10–6 Ω to 0.7 × 10–6 Ω), above 2 order higher donor charge density (from 3.58 × 1018 cm−3 to 1.41 × 1021 cm−3), and reduced limit of detection (from 32.3 μM to 2.8 μM) in comparison to plain T-NTs based sensor. In addition, the sensitivity reported here is significantly higher than most of the previously reported TiO2 based dopamine sensors. Perspective-wise, the dual treatment approach is a promising technique and is highly desirable for enhancing the performances of T-NTs and other nanomaterial based electrochemical sensors.

The Impact of Side-Selective Laser Tailoring of Titania Nanotubes on Changes in Photoelectrocatalytic Activity

“…The process upscaling requires several optimization steps, and the elaborated route can only be performed at the laboratory scale and cannot be carried out on only a specific part of the substrate. In contrast to these limitations, laser technology offers rapid and easily scalable processing based on the interaction between the coherent, intense light of a particular wavelength with the material [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. Additionally, the selection of the laser fluence and the environment in which the process is carried out (vacuum, ambient atmosphere, or ever water) can also be included into the group of important parameters affecting the final product [ 39 , 40 ] (see Table 1 ).…”