Synthesis, Self-Organization And Electrochemical Study Of Prussian Blue And Its Analogue-Based Nano Ordered Structures

The Prussian blue (PB) and its analogues exemplify mixed-valence compounds. Many PB and its analogues exhibit interesting (even extraordinary), electrochromic, photophysical, magnetic, optical and excellent electrochemical stability. They also have the great potential for device applications, therefore, PB and its analogues are widely used in many fields, such as electroanalytical chemistry, electrocatalysis, sensors, electrochromism, photoresponse, molecular magnets, nanowires, rechargeable battery devices. In recent years, the study of their high electrocatalytic properties and detection performance of PB and its analogue modified electrode has made some progress.In this paper, PB and its analogue nanomaterials with electrical activity were synthesized by chemical synthesis and electrochemical synthesis methods. The products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultra-visible spectrometer (UV-vis)and so on.The research in this work includes four parts, as follows:1. The structure, character and preparation of PB and its analogues were summarized. The application and study in the field of chemically modified electrode were described in detail. The property and function of a variety of PB nanomaterials were introduced. Then, the research objectives and research mentality of this thesis were also represented. 2. A strategy of one-step synthesis and self-organization of polypyrrole (PPy) ultrathin films inlayed with PB nanoparticles was described. The formation of ultrathin films is induced by a drop of toluene solution on water surface, and the organization process is accompanied by the shrinkage of organic layer area on water surface due to the evaporation of toluene. On the one hand, the combination of the downward gravity force from the toluene solution of pyrrole and its upward buoyancy force drives the toluene solution of pyrrole to collapse downwards and scatter outwards on water surface. On the other hand, the strong adhesion ability of PPy and the hydrophobic action between the toluene solution of pyrrole and water drives the upper organic layer to reunite. All of these forces yield a close-packed ultrathin PPy films with inlayed PB nanoparticles. Due to the existence of PPy, the yield ultrathin films inlayed with PB could be easily transferred and anchored onto the surface of glass carbon.3. The work reports on the characterization, assembly and electroanalytical performance of PBPPy composite nanoparticles synthesized in a stirring conditions by chemical synthesis method. SEM suggests the formation of nanosized PBPPy particles with the diameter between40-50nm. UV-vis spectroscopy and FTIR studies confirm that they are composed of Prussian blue and polyrrole. PB and PBPPy nanoparticles were anchored onto the surface of glass carbon electrodes. CV experiments show that PB or PBPPy-modified electrodes exhibit their intrinsic electrochemical properties and high electrocatalytic activity towards H2O2. PBPPy modified electrodes give higher sensitivity to H2O2response than PB-modified electrode.4. Electrochemical conversion of metal hexacyanoferrates into their oxides or hydroxides has been successfully achieved and reported using nickel hexacyanoferrates (Ni-HCF). To the best of our knowledge, electrochemical conversion of metal hydroxides into their hexacyanoferrates has not been reported before. Herein, a versatile strategy for such a conversion was explored by potential cycling Ni(OH)2nanoparticle film modified electrodes in K3[Fe(CN)6] or K4[Fe(CN)6] solution. The results show that K3[Fe(CN)6] is more prone to the conversion from Ni(OH)2to Ni-HCF. Their composition, morphology, and structure were characterized by the techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and UV-vis spectrometry. The reaction mechanism is tentatively given. This strategy is suitable for the other metal hydroxides including rare earth hydroxides such as neodymium and samarium etc.