Bismuth oxide (Bi2O3) decorated titania nanotube array (T-NT) composite materials were synthesized by a simple, yet versatile electrodeposition method. The effects of deposition current density and time on morphology evolution of the bismuth oxide phase were analyzed. It was found that an optimum deposition condition in terms of current density and time could be reached to achieve uniform and equiaxed crystal morphology of the deposited oxide phase. The morphology, shape, size distribution, and crystal structure of the bismuth oxide phase were evaluated using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopic techniques. The electrochemical capacitance of the T-NT/Bi2O3 composites was studied by conducting cyclic voltammetry and galvanostatic charge-discharge experiments. These studies indicated that the capacitance behavior of the composite material was dependent on the morphology and distribution of the bismuth oxide phase. The capacitance was greatly enhanced for the composite having equiaxed and uniformly distributed bismuth oxide particles. The maximum interfacial capacitance achieved in this study was approximately 430 mF cm(-2). Galvanostatic charge-discharge experiments conducted on the composite materials suggested stable capacitance behavior together with excellent capacitance retention even after 500 cycles of continuous charge-discharge operation.

Metal oxide nanotubes have become a widely investigated material, more specifically, self-organized titania nanotube arrays synthesized by electrochemical anodization. As a highly investigated material with a wide gamut of applications, the majority of published literature focuses on the solar-based applications of this material. The scope of this review summarizes some of the recent advances made using metal oxide nanotube arrays formed via anodization in solar-based applications. A general methodology for theoretical modeling of titania surfaces in solar applications is also presented.

Self-assembled arrays of titania nanotubes are synthesized via electrochemical anodization of Ti foils under the presence of UV-vis irradiation. Compared to control samples (anodized without light), the light-assisted anodized samples exhibit larger diameters as well as thicker nanotube walls, whereas the length of the nanotubes remains the same under otherwise similar synthesis conditions. Enhanced photoelectrochemical performance with light-assisted anodized samples under simulated AM 1.5 irradiation is observed by an increase in photocurrent density of 45-73% at 1.23 V (RHE). The enhanced photoelectrochemical performance is correlated to improved charge separation analyzed by Mott-Schottky. A mechanism on the photoeffect during anodization is presented. The morphology and improved properties obtained from the synthesis methodology may also find application in other fields such as sensing and catalysis.

A facile electrochemical technique has been employed to fabricate titania nanotube (T-NT)/cobalt sulfide (CoS) composite electrode for high performance supercapacitor application. The morphology and phase evaluation of the electrode were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. The pseudocapacitance behavior of the T-NT/CoS composite electrode has been evaluated in four different aqueous electrolytes: KOH, KCl, Na 2 SO 4 and Na 2 SO 3. Cyclic voltammetric studies in aqueous KOH electrolyte indicated that a very high specific capacitance (370 F g-1) can be achieved in this electrolyte together with excellent cycle stability even after 300 consecutive CV cycles. Further, the capacitance behavior of the T-NT/CoS electrode in KCl, Na 2 SO 4 , and Na 2 SO 3 electrolytes exhibited a mixture of electric double layer (EDL) and redoxinduced supercapacitance as displayed in the cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopic (EIS) experiments. It was also observed that the capacitance behavior of the composite material is not greatly dependent on the electrolyte used

The article demonstrates the influence of annealing temperature on the supercapacitance behavior of iron oxide nanotube synthesized on pure iron substrate by electrochemical anodization process. Anodization was performed in an ethylene glycol solution containing 3% H 2 O and 0.5 wt. % NH 4 F. The as-anodized nanotubes were annealed in an ambient atmosphere at various temperatures ranging from 200 to 700ºC for a fixed duration of time (2hrs). The morphology and crystal phases developed after anodization and subsequent annealing processes were examined using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and X-ray photospectroscopy (XPS). Cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) experiments were performed in 1 M Li 2 SO 4 to evaluate the electrochemical capacitance properties of the oxide nanotube electrodes. It was found that the electrode annealed at 300°C exhibited superior electrochemical capacitance compared to the electrodes annealed at other temperatures. The highest specific capacitance achieved after annealing at 300°C was about 314 mF cm-2. The