Black Titanium Oxide Nanotubes Deposited with Fe (III) Oxide Nanoparticles for Electrochemical Sensing of Dopamine

摘要

Abstract TiO2 nanotubes have been electrochemically reduced to form black TiO2 nanotube (BTNT) electrodes for improved loading and enhanced electrocatalytic properties of Fe2O3 nanoparticles for sensing dopamine. The nanoparticles were electrodeposited on the BTNTs by a chronoamperometric technique. The sensing electrodes were analyzed for their morphological, electrical, and chemical properties using scanning electron microscopy, UV–Vis spectroscopy, x-ray diffractometry, and x-ray photoelectron spectroscopy. All the electrochemical sensing properties of the electrodes were analyzed using cyclic voltammetry and chronoamperometry techniques. The Fe2O3 nanoparticles loaded on the BTNTs showed an excellent sensitivity of 0.81 mA mM−1 cm−2, which is more than 2 times higher compared to Fe2O3 nanoparticles deposited on unreduced TiO2 nanotubes. Further, the sensor was highly selective towards dopamine in comparison to glucose, ascorbic acid, uric acid, and l-cystine. The improved sensing properties are due to the increased electron transfer rate and reduced band gap of the BTNTs (2.9 eV), which provided a higher electrocatalytic current to the Fe2O3 nanoparticles for sensing dopamine. Overall, an efficient dopamine sensor can be developed by using simple electrochemical reduction and electrodeposition techniques.Graphical Abstract