Synthesis and Characterization of Metal-Hexacyanometallates as Innovative Materials for Analytical and Technological Applications

This thesis focuses on the synthesis, characterization and analytical and technological applications of Prussian Blue analogues (or Metal Hexacyanometallates, MHCMs), with the generic formula AxMy[B(CN)6].mH2O where, x, y, and m are stoichiometric coefficients, M and B indicate transition metals and A an alkaline metal cation. Prussian Blue (PB) open framework materials exhibit unique physicochemical characteristics, that are primarily a result of the perovskite-like face-centered cubic crystal structure and represent a class of extremely versatile compounds. Properties and structures of these chemically and electrochemically synthetized compounds, both native and composite, are investigated by using a multi-technique approach including X-ray Powder Diffraction (XRD), X-ray fluorescence spectroscopy (XRF), X-ray Absorption Spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Infrared Spectroscopy (IR), Ultraviolet–visible spectroscopy (UV-Vis) and electrochemical measurements. Electrocatalysis of targeted reactions and structural changes upon ion uptake by these MHCF nanoparticles constitute an important topic in this thesis. The use of Prussian blue and its analogues in devices for displays and “smart” windows, environmental remediation, chemical/biological sensing, energy conversion, and magneto-optic/opto-magnetic switching is described, giving a general overview of innovative analytical and technological applications provided by such materials. Finally, the synthesis and characterization of novel TiO2–Metal Hexacyanometallates composite materials is studied. The electronic properties of TiO2 were substantially modified as confirmed by UV-Vis and XP-valence band data. Practical use of these materials can be envisaged in different areas, such as antibacterial treatments, protection of historical artifacts, self-cleaning surfaces, photovoltaic cells and photoelectrochemical degradation of organic dyes in aqueous solutions under UV irradiation.