Highly Ordered Vertical Arrays of TiO<SUB>2</SUB>/ZnO Hybrid Nanowires: Synthesis and Electrochemical Characterization

Abstract

We report the fabrication of vertically aligned hierarchical arrays of TiO2/ZnO hybrid nanowires, consisting of ZnO nanowires grown directly from within the pores of TiO2 nanotubes, through a combination of electrochemical anodization and hydrothermal techniques. These novel nano-architectured hybrid nanowires with its unique properties show promise as high performance supercapacitor electrodes. The electrochemical behaviour of these hybrid nanowires has been studied using Cyclic voltammetry, Galvanostatic charge-discharge and Electrochemical impedance spectroscopy (EIS) measurements using 1.5 M tetraethylammoniumtetrafluoroborate in acetonitrile as the electrolyte. Excellent electrochemical performances with a maximum specific capacitance of 2.6 mF cm-2 at a current density of 10 µA cm-2, along with exceptional cyclic stability, have been obtained for TiO2/ZnO-1 h hybrid material. The obtained results demonstrate the possibility of fabricating new geometrical architectures of inorganic hybrid nanowires with well adhered interfaces for the development of hybrid energy devices.

Fabrication and Characterization of Highly Sensitive Acetone Chemical Sensor Based on ZnO Nanoballs

“…These chemisorbed oxygenated anionic species deplete the surface electron states of the ZnO and increase the resistance of the n-type semiconductor material due to the formation of an electron depletion layer at the ZnO nanoballs surfaces [ 58 , 59 , 60 , 61 ]. The increase in the current response is due to the release of the trapped electrons back into the conduction band during the catalytic oxidation the adsorbed acetone molecules into CO 2 and H 2 O (Equations (7)–(10)) [ 18 , 44 , 62 , 63 , 64 ].…”

Review—Advent of TiO2Nanotubes as Supercapacitor Electrode

“…The enhanced electrochemical activity of TiO 2 and higher conductivity of ZnO is responsible for the superior performance of composites compared to bare TiO 2 (0.8 mFcm −2 ) and ZnO (0.6 mFcm −2 ). 103 Similarly, random shaped ZnO is deposited over nanotube arrays by potentiostatic deposition method. The deposition is carried out at a potential of −1.25 V in a threeelectrode setup using 10 mM ZnCl and 0.5 M KCl at 60 • C. The TiO 2 /ZnO composite exhibits a specific capacitance of 302 Fg −1 at a scan rate of 20 mVs −1 .…”