>Magister Scientiae - MSc / A comparative study of electrolysers using different anodic materials for the electrolysis of brine (sodium chloride) for the production of sodium hypochlorite as a source of available chlorine for disinfection of rural water supplies has been undertaken. The electrolyser design used was tubular in form, having two chambers i.e. anode inside and cathode outside, separated by a tubular inorganic ceramic membrane. The anode was made of titanium rod coated with a thin layer of platinum and a further coat of metal oxide. The cathode was made of stainless steel wire. An assessment of these electrolysers was undertaken by studying the effects of some variable parameters i.e.current, voltage and sodium chloride concentration. The cobalt electrolyser has been shown to be superior as compared to the ruthenium dioxide and manganese dioxide electrolysers in terms of hypochlorite generation. Analysis of hydroxyl radicals was undertaken since there were claims that these are produced during brine electrolysis. Hydroxyl radical analysis was not successful, since sodium hypochlorite and hypochlorous acid interfere using the analytical method described in this study. / South Africa

Magister Scientiae - MSc / This study has shown that OHË radicals can be generated in an Fe/O2 cell from the electrode products via Fenton’s reaction and used for water disinfection. The cell system in which the experiments were carried out was open and undivided and contained two electrodes with iron (Fe) as the anode and oxygen (O2) gas diffusion electrode. Typically, 100 ml of Na2SO4.10H2O (0.5M) solution was used as a background electrolyte. OHË radicals were produced in-situ in an acidic solution aqueous by oxidation of iron (II), formed by dissolving of the anode, with hydrogen peroxide (H2O2). The H2O2 was electrogenerated by reduction of oxygen using porous reticulated vitreous carbon (RVC) as a catalyst. / South Africa

Finding materials based on non-rare earth metals is vital for the global transition to a more sustainable economy. Discovering useful properties in common metal oxides is a promising avenue for new materials. In this work we have investigated the properties of Ru(x)CoMo(1-x) to evaluate the feasibility of its use as an electrocatalyst for the oxygen evolution reaction (OER). Herein, the plasma spray deposition on FTO and glass is reported as a method for production of low Ru content-CoMo oxide. The material showed a good performance in an alkaline electrolyte for OER, with no loss on stability and overpotentials to achieve a current density of 10 mA cm-2 of 528, 483, 455, 439 mV for 0, 10, 20, and 30 At% of Ru, respectively. The final material is shown to be composed entirely of Co and Mo oxides, as well as Ru which is present in the crystal structure of these metal oxides as observed using optical characterization techniques, XRD, Raman and SEM. With the aim of maximising performance and decreasing the amount of Ru used, we find a Ru content of 20 At% is most optimal for OER in alkaline. We find therefore Ru(0.2)(CoMo)(0.8) to be an effective electrocatalyst for OER in alkaline, while examples from literature outperforms it in other applications, it is still a good basis for further work and development.

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At the present time there is a widespread interest in the chemistry of boron. Especially is this true in the field of organo-boron compounds, for boron has been found to possess the property of forming ring and chain compounds with itself or with certain organic groups. Many organo—boron compounds may be prepared by standard organic reactions. Interest has developed in the possible electrochemical formation of boron-containing organic compounds. A considerable saving in materials of construction, power, and reaction time may result if these syntheses are performed electrochemically. The formation of organo-boron compounds may be accomplished through the anodic formation of a free alkyl radical by electrolyzing a solution of an alkyl alkali compound such as lithium ethyl, along with a simultaneous electrolysis of an alkali borohydride. The deposition of the free alkyl radical in the presence of the borohydride radical may result in a reaction between the two. The purpose of this investigation was to study the electrolysis of diethyl ether solutions of lithium methyl, lithium ethyl, lithium butyl, or ethyl magnesium bromide in the presence of lithium borohydride. / Master of Science

Bakalauro darbą „Plazmoelektrolitinio proceso stabilumo sąlygų tyrimas“ sudaro įvadas, 3 skyriai, išvados, literatūros sąrašas, priedai ir 1 kompaktinis diskas. Darbo apimtis 39 puslapiai. Darbe pateikti 26 paveikslai, 1 lentelė. Įvade iškeliama darbo problema, pagrindinis tikslas ir uždaviniai. Pirmąjame skyriuje pateikiami pagrindiniai teoriniai teiginiai apie procesus sudarančius vandenilio plazminę elektrolizę: elektrolizę ir plazmą. Antrąjame skyriuje analizuojami ir aptariami moksliniai straipsniai, kuriuose kalbama apie atliktus vandenilio plazminės elektrolizės proceso tyrimus. Išryškinami tyrimai, kurie susiję su šio proceso stabilumo stebėjimais. Trečiajame skyriuje aptariami atlikto plazmoelektrolitinio proceso stabilumo sąlygų tyrimo rezultatai ir pateikiama jų analizė. / The Bachelor paper “The investigation of the stability conditions of plasma electrolysis process ” consists of introduction, three chapters, conclusions, literature source, additions and 1 CD. The volume of this work is 39 pages. There are 26 pictures and 1 table in this work. Work problem, objective and goals are provided in the introduction. The first chapter is provided main theoretical propositions about processes which take part in hydrogen‘s plasma electrolysis: electrolysis and plasma. Second chapter analyze and review scientific articles about hydrogen’s plasma electrolysis research. The paper underlines studies, related to mentioned process and it’s monitoring of stability. In the third chapter a reader will find the results and their analysis about stability conditions of plasma electrolysis process.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19730号 / 工博第4185号 / 新制||工||1645(附属図書館) / 32766 / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 江口 浩一, 教授 安部 武志, 教授 陰山 洋 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The research presented is based on alternative anode materials for high temperature steam electrolysis. The key to commercially viable renewable energy economy is based on energy storage of intermittent sources. Hydrogen is the preferred form of energy storage for solid oxide electrolysis cells. However, conventional anode material lanthanum strontium manganite (LSM), suffers from poor ionic conductivity, thus prohibiting much of the bulk electrode from providing an enhanced electrochemical performance. This study explores the use of a double-layered perovskite system with mixed electronic and ionic conductivity for use as anode material. Specifically, the SmBa₁₋ₓSrₓCo₂O[sub](5+δ) system (SBSCO) is analyzed for characteristics that may enhance the performance and feasibility of SBSCO as an alternative anode material to LSM. Previous in-house work showed SmBa₀.₅Sr₀.₅Co₂O[sub](5+δ) had the lowest area specific resistance of any double- layered material reported. Here the system is further explored by studying the full range of compositions. From X-ray diffraction analysis, increased Sr substitution leads to a tetragonal phase change in SBSCO. High temperature x-ray diffraction of compositions showed thermal stability of structure. Magnetization measurements are reported for selected compositions. The stability of SBSCO was examined in CO₂ containing atmospheres. Despite containing alkaline earth metals, the system offers limited CO₂ tolerance. A set of thermodynamic parameters is presented based on CO₂ partial pressure and temperature. Model indicates SBSCO is a stable electrode material for both electrolysis and fuel cell modes. Compositions were tested for steam electrolysis performance with the use of YSZ electrolyte, and Ni-YSZ and La₀.₄Sr₀.₄Ni₀.₀₆Ti₀.₉₄O₂.₉₄ cathodes. SmBa₀.₃Sr₀.₇Co₂O[sub](5+δ) had the highest performance for compositions (0≤x≤1) based on I-V curves and impedance measurements. Stability tests were conducted in potentiostatic mode and no delamination was observed for SBSCO in microstructural analysis after testing. From these studies, SBSCO is demonstrated to be a suitable for application in electrolysis and an alternative for LSM as anode material.

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