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The growth of tungsten oxide was carried out on microscope glass substrates using the one-pot direct hydrothermal method. Despite the simplicity of the technique, the coating grown using 0.3 M NaOH at 95 C after 30 h, exhibited reversible electrochemical response without significant degradation, as studied by cycling voltammetry experiments for at least 250 times in a solution of 1 M LiClO 4 . This coating at the same time presented marked photocatalytic activity under solar illumination, degrading stearic acid by 52%. The results are discussed in terms of the materials' observed morphology towards which, the role of the growth solution chemistry is examined.

Amorphous vanadium pentoxide coatings were electrodeposited at room temperature on ITO glass substrates using a solution of vanadyl (IV) acetylacetonate in methanol. The electrochemical performance of the coatings as a function of deposition current density was studied using a classical three-electrode potentiostatic cell system and a solution of 1 M LiClO 4 in polypropylene carbonate as an electrolyte. The sample grown using deposition current density of 1 mA cm −2 was found to exhibit the best electrochemical activity in terms of the fastest bleaching kinetics and the highest charge storage due to the increased roughness of the structure.Vanadium pentoxide has attracted a considerable interest for its potential application in lithium-ion batteries and electrochromics. 1-3 In both applications, lithium ion insertion into vanadium oxide follows the reactionHowever, the charge capacity and charging-discharging response are limited by the low diffusion coefficient of Li ions in the V 2 O 5 matrix. 4,5 Improvements have been demonstrated by porous materials because they provide high surface area resulting in a higher charge capacity and a very short diffusion path for lithium ions allowing rapid charging-discharging response. 6,7 Physical and chemical methods have been used for the fabrication of vanadium oxides including sputtering, 8,9 pulsed laser deposition, 10,11 chemical vapor deposition, 12-14 sol-gel, 15 hydrothermal growth 16 and electrodeposition. 17 Among these, electrodeposition has many advantages over the other methods in terms of economical and environmental benefits since low temperatures are employed and no toxic chemicals are required. In addition, the morphological and structural characteristics of the final products can be simply controlled by varying the deposition current density, deposition voltage, electrolyte's properties and deposition time. 18 In this work, electrodeposition was used to fabricate vanadium oxide coatings at room temperature. The effect of deposition current density on the morphological and electrochemical performance of the oxides was investigated. ExperimentalA three-electrode electrochemical cell was utilized for the deposition of vanadium oxide coatings. Platinum, Ag/AgCl and ITO glass substrates were used as the counter, reference and working electrodes respectively. The electrolyte was a 0.04 M green solution of vanadyl acetylacetonate (VO(acac) 2 ) in methanol (CH 3 OH). Prior to electrodeposition, indium tin oxide (ITO) glass substrates were ultrasonically cleaned with 2-propanol, acetone, MilliQ H 2 O and dried with N 2 . The deposition of the oxides was carried out using deposition current densities of 0.5, 0.7 and 1 mA cm −2 for constant deposition time of 120 min. Finally, each freshly deposited sample was dried in air at room temperature. z E-mail: dimitra@iesl.forth.gr X-ray diffraction (XRD) measurements were performed using a Siemens D5000 Diffractometer for 2θ = 10.0-60.0 degs. Raman measurements were performed in a Nicolet Almega XR micro-Raman system using...

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