In the present work, a new WO 3 nanostructure has been obtained by anodization in a H 2 SO 4 /NaF electrolyte under controlled hydrodynamic conditions using a Rotating Disc Electrode (RDE) configuration. Anodized samples were analyzed by means of Field Emission Scanning Electronic Microscopy (FE-SEM), Confocal Raman Microscopy and photoelectrochemical measurements. The new nanostructure, which consists of nanoplatelets clusters growing in a tree-like manner, presents a very high surface area exposed to the electrolyte, leading to an outstanding enhancement of its photoelectrochemical activity. Obtained results show that the size of nanostructures and the percentage of electrode surface covered by these nanostructures depend strongly on the rotation velocity and the electrolyte composition.

Single crystals built up from octahedral Mo 6 cluster units, with appropriate geometry and size, constitute Fabry−Peŕottype optical microcavities with well-defined resonances. Such resonances appear in the VIS-NIR range when performing optical transmittance (OT) or photoluminescence (PL) measurements. They strongly depend on the crystal thickness and on the optical constants of the material, specifically the real and imaginary parts of the refractive index. In this work, the accurate measurement of the crystal thickness is used for the determination of the optical constants by means of a fitting process, and the preferred orientation of the crystals was determined by X-ray diffraction.

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