Sintesi e caratterizzazione di Bi2MoO6 per applicazione in celle fotoelettrochimiche

In this thesis, the possibility of utilising Bi2MoO6 Aurivillius semiconductor as a photoelectrode for the efficient utilisation of the solar energy in photoelectrochemical cells (PECs) was deeply investigated. The material was directly synthesized with a one-step hydrothermal synthesis from precursors solution without calcination step, in the form of nanostructured powder. Moreover, in the same way, nanostructured thin layer was directly grown on conductive FTO-glass to form a photoelectrode. The powders were characterized with X-Ray Diffraction technique (XRD) and Scanning Electron Microscopy (SEM) to evaluate structural and morphological properties, and specific surface area was determined by Brunauer-Emmett-Teller (BET) analysis. Band gap value and photocatalytic activity towards Rhodamine B decomposition were evaluated to define optical properties and photo-catalytic ones. Thin films of Bi2MoO6 directly grown on FTO glass showed three different morphologies: Nano-Rods (NR), Nano-Sheet (NS) and Homo-Junction (HJ) at different synthesis conditions; the influence of precursors concentration and reaction time on the obtaining of these structures was discussed. Then, XRD and SEM analyses were conducted on thin layers as well, and band gap value determination confirms the ability of these photoelectrodes to adsorb Visible light. These systems were fully characterized by Mott-Schottky analysis (MS), Electrochemical Impedance Spectroscopy (EIS), Linear Sweep Voltammetry (LSV) and chronoamperometry analyses, and the correlation between morphological and photoelectrochemical properties was found and discussed. The results confirm that Bi2MoO6 materials can be used to prepare photoelectrodes and show the potentiality of the one-step hydrothermal synthesis to obtain nanostructured systems with good photoelectrochemical properties.