Substrates with localized, organic radicals have the ability to attack `inert' surfaces to form covalent bonds between the substrate and an atom at the surface. These radicals can be generated in electrochemical experiments with substrates bearing an electroactive moiety. The moiety after oxidation (loss of an electron) or reduction (gain of an electron) generates the active radical. Electron transfer reactions at an electrode surface generate a high population of these radicals, thereby facilitating attachment. The electrochemical oxidations of compounds containing terminal alkynes and alkenes were found to be effective methods for covalent attachment to glassy carbon, gold, and platinum electrodes. Modified electrodes were studied for their fundamental electrochemistry with an emphasis on organometallics at the surface and to determine the effect of weakly coordinating anions in heterogeneous electrochemistry. Ferrocene, Fe(η5-C5H5)2, was employed predominantly in this research, as it has robust neutral and cationic states, making it a superior electron transfer agent. A number of other compounds prominent in organometallic electrochemistry, such as ruthenocene (Ru(η5-C5H5)2), cymantrene (Mn(η5-C5H5)(CO)3), cobaltocenium ([Co(η5-C5H5)2]+), and benzene chromium tricarbonyl (Cr(η6-C6H6)(CO)3), were also studied at modified surfaces. A novel method was developed employing the anodic oxidation of ethynyl-lithium compounds to modify electrodes. Oxidation of the carbon-lithium bond leads to an alkyne radical and the loss of lithium ions to solution. The desired radical can be formed either by intramolecular electron-transfer mediation by pendant ferrocenium ions or by the direct oxidation of the ethynyl-lithium bond. These experiments successfully led to the appearance of new surface waves at the electrode. The new surface waves were assigned to the parent molecule of interest based on its electrochemical properties, i.e. its potential, and the electrochemical and chemical reactivity of the redox process. A second general method was developed for terminal alkynes and alkenes which eliminated the need for chemical pre-treatment and lithiation of the alkyne. The direct oxidation of unsaturated carbon-carbon bonds at higher potentials forms the active radical after loss of a proton. The direct oxidation was extended to the organic compound, tetraphenylporphyrin. Porphyrins are a widely used molecular scaffold in naturally occurring compounds such as chlorophyll and heme, and can be applied in optics and electronics due to their intense optical properties. These two approaches hold promise as general anodic methods for electrode modification, and for applications in chemical analysis and catalysis.

Molecular light emitting diode, including organic light emitting diode (OLED) and polymer light emitting diode (PLED), is commonly consist of one or several molecular layer(s) sandwiched between an anode and a cathode. When electrons and holes are injected respectively from cathode and anode into the molecular layer by a bias voltage, these two types of carriers migrate towards each other and a fraction of them recombine to form light emission. The focus of this study is electrode modifications of molecular light emitting diode. The electrode modifications include using a low work function cathode material, a high work function anode material or inserting a very thin electrode modifier between molecular layer and electrode for enhancing the electron or the hole injection efficiency leading to higher electroluminescence emission and/or lower threshold voltage. Low work function metal, Mg, could effectively reduce the electron injection barrier between molecular layer and cathode leading to better emission brightness and threshold voltage. A monolayer rigid-rod poly-p-phenylenebenzobisthiazole (PBT) or poly-p-phenylenebenzobis- oxazole (PBO) PLED with Mg cathode demonstrated a low threshold voltage of 3 V. Besides, a very thin layer of LiF (or Al2O3) inserted between molecular layer and Al cathode was applied to enhance the electron injection efficiency leading to a stronger electroluminescence intensity and a low threshold voltage of 2.8 V. On anode modification, a thin PBO layer was inserted between molecular layer and the indium-tin-oxide (ITO) substrate for improving the electroluminescence emission brightness and the threshold voltage. The PBO modified anode could effectively enhance the electro- luminescence intensity and lower the threshold voltage to 1 V~ 3 V on several mono- or multi-layer molecular light emitting diodes. Besides, a novel ITO substrate cleaning method via acid treatment was applied for increasing the work function of ITO to effectively enhance the hole injection efficiency.

Layer-by-Layer (LbL) deposition of electrochemically active materials on porous carbon electrodes is a proven method to leverage both electrochemical double-layer capacitance and pseudocapacitance for charge storage on the same electrode. LbL coatings are held together by electrostatic attraction between adjacent layers of oppositely charged molecules. Previous studies have used Keggin polyoxometalates to great effect as the anionic layer in LbL electrode modification, but little effort has been devoted to cationic material selection and LbL process optimization. This work investigated alternatives to the conventional, electrochemically inert polydiallyldimethylammonium (PDDA) cation. The use of fuchsin molecular cations in LbL deposition improved the specific energy and specific power of modified electrodes. Fuchsin cation also rendered the environmentally harmful oxidative surface activation step unnecessary for LbL deposition. Process parameters were optimized for MWCNT/Fuchsin/POM samples, and post-LbL electrochemical polymerization was found to further improve the performance of these electrodes.

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This work was focused on study of a behaviour of the food additivum butylated hydroxyanisole on modified carbon electrodes by the voltammetric techniques - cyclic and differential pulse voltammetry. Glassy carbon and carbon paste electrode were used. Multiwalled carbon nanotubes (MWCNT) in combination with three different binders (acetonitrile, nafione or chitosane) were employed for the electrode modification. Carbon paste electrode was unable to modificate with film containing carbon nanotubes and acetonitrile, its active surface was treated only with nafione and chitosane film. All three mentioned modifications were applied in case of glassy carbon electrode. Butylated hydroxyanisole provided a significantly higher signal using electrodes modified with carbon nanotubes with all three binders in contrast to electrodes without any surface modification. The glassy carbon electrode with carbon nanotube / acetonitrile film on its surface appeared to be the most effective for analytical purposes. Voltammetric determination of butylated hydroxyanisole using this electrode provided a better defined and higher analytical signal and lower relative standard deviations in comparison with other ways of modification. The limit of detection of butylated hydroxyanisole obtained by cyclic voltammetry on glassy...

Объектом исследования являются электроды на основе нанотубулярного диоксида титана, модифицированные различными способами (термическая обработка, создание композитов с углеродными нанотрубками и частицами металлического никеля). Синтезированные образцы исследовались методом растровой электронной микроскопии и различными электрохимическими методами анализа (гальваностатический заряд-разряд, циклическая вольтамперометрия, импедансная спектроскопия). В результате исследования получены электроды: 1) Т/TiO2-НТ; 2) УНТ/TiO2-НТ; 3) Ni/TiO2-НТ представляющие собой: 1) массивы TiO2-НТ толщиной 3,5 мкм, с внутренним диаметром 70-80 нм и толщиной стенок 30-40 нм; 2) массивы TiO2-НТ с углеродными нанотрубками диаметром 10-30 нм и длиной от десятков нм до десятков мкм на поверхности оксидного слоя; 3) массивы TiO2-НТ, декорированные сферическими наночастицами Ni диаметром 70-100 нм с образованием локальных конгломератов частиц до 500 нм. Результаты работы позволили получить информацию об электрохимических характеристиках синтезированных электродов и преимуществах модификации структур TiO2-НТ для использования их в качестве электродов ионистров. / The object of this research is electrodes based on nanotubular titanium dioxide, modified by various methods (thermal treatment, synthesis of composites with carbon nanotubes and metallic nickel particles). The synthesized samples were investigated by scanning electron microscopy and various electrochemical analysis methods (galvanostatic charge-discharge, cyclic voltammetry, impedance spectroscopy). As a result of the study, were obtained: 1) T/TiO2-NT; 2) CNT/TiO2-NT; 3) Ni/TiO2-NT electrodes, which are: 1) arrays of TiO2-NT 3.5 μm thick, with an inner diameter of 70-80 nm and wall thickness 30-40 nm; 2) arrays of TiO2-NT with carbon nanotubes with a diameter of 10-30 nm and a length from tens of nm to tens of microns on the surface of the oxide layer; 3) arrays of TiO2-NT, decorated with spherical Ni nanoparticles with a diameter of 70-100 nm with the formation of local conglomerates of particles up to 500 nm. The results of the work made it possible to obtain information on the electrochemical characteristics of the synthesized electrodes and the advantages of modifying the TiO2-NT structures to use them as supercapacitor electrodes.