Isoelectric trapping (IET) has become an accepted preparative-scale electrophoretic separation technique. However, there are still a number of shortcomings that limit its utility. The performance of the current preparative-scale IET systems is limited by the serial arrangement of the separation compartments, the difficulties in the selection of the appropriate buffering membranes, the effect of Joule heating that may alter separation selectivity and a lack of methods for the determination of the true, operational pH value inside the buffering membranes. In order to bolster the current membrane pH determination methods which rely on the separation of complex ampholytic mixtures, a fluorescent carrier ampholyte mixture was synthesized. The use of a fluorescent mixture allows for a reduced load of carrier ampholytes, thereby reducing a possible source of error in the pH determinations. A mixture of carrier ampholytes tagged with an alkoxypyrenetrisulfonate fluorophore was shown to have suitable fluorescence and ampholytic properties and used to accurately determine the pH of high pH buffering membranes under actual IET conditions. In a more elegant solution to the difficulties associated with pH determinations, a method utilizing commercial UV-transparent carrier ampholytes as the ampholyte mixture to be separated was developed. By using commercial carrier ampholytes and eliminating the need to synthesize, purify, and blend fluorescently tagged ampholytes, the new method greatly simplified the determination of the operational pH value of the buffering membranes. In order to address the remaining limitations, a new system has been developed that relies on (i) parallel arrangement of the electrodes and the collection compartments, (ii) a directionally-controlled convection system for the delivery of analytes, (iii) short anode-to-cathode distances, (iv) short intermembrane distances, and (v) an external cooling system. This system has been tested in four operational modes and used for the separation of small molecule ampholytic mixtures, for the separation of protein isoforms, and direct purification of a target pI marker from a crude reaction mixture.

<p>In this study novel composite electrodes were developed, in which the catalytic components were deposited in nanoparticulate form. The efficiency of the nanophase catalysts and membrane electrodes were tested in an important electrocatalytic process, namely hydrogen production by water electrolysis, for renewable energy systems. The activity of electrocatalytic nanostructured electrodes for hydrogen production by water electrolysis were compared with that of more conventional electrodes. Development of the methodology of preparing nanophase materials in a rapid, efficient and simple manner was investigated for potential application at industrial scale. Comparisons with industry standards were performed and electrodes with incorporated nanophases were characterized and evaluated for activity and durability.</p>

Cette étude porte sur la co-électrolyse de H2O et CO2 à 800°C dans une cellule à oxydessolides. Un modèle détaillé a été développé afin de rendre compte des phénomènesélectrochimiques, chimiques, thermiques et de transferts de matière, et introduisant unereprésentation macroscopique du mécanisme de co-électrolyse. Il permet d’estimer lesperformances et les compositions en sortie de cellule. Un protocole expérimental, visant àvalider les principales hypothèses de ce modèle, a été appliqué à deux types de cellulecommerciale à cathode support. À partir de courbes de polarisations, obtenues en électrolyseet en co-électrolyse, ainsi que d’analyses gaz, les densités de courant d’échange, illustrant lescinétiques électrochimiques, ont pu être estimées, et le mécanisme proposé a pu être validé.L’analyse des simulations a permis l’identification des processus limitant la co-électrolyse, laproposition de voies d’optimisation et l’établissement des cartographies de fonctionnement. / This work investigates the high temperature co-electrolysis of H2O and CO2 in Solid OxideCells. A detailed model was developed, encompassing electrochemical, chemical, thermal andmass transfer phenomena, and introducing a macroscopic representation of the co-electrolysismechanism. This model allows predicting the performances and outlet compositions in singlecell and stack environments. An experimental validation protocol was implemented on twotypes of commercial Cathode Supported Cells, ranging from polarization curves, obtained insingle and co-electrolysis modes, to micro gas analyses. These tests aimed both at determiningthe different exchange current densities, representative of the kinetics of electrochemicalreactions, and validating the simulated cell global behavior and mechanism proposed.Comprehensive analysis of the simulations led to the identification of limiting processes andpaths for optimization, as well as to the establishment of co-electrolysis operating maps.

Doctor Scientiae - DSc / In this study novel composite electrodes were developed, in which the catalytic components were deposited in nanoparticulate form. The efficiency of the nanophase catalysts and membrane electrodes were tested in an important electrocatalytic process, namely hydrogen production by water electrolysis, for renewable energy systems. The activity of electrocatalytic nanostructured electrodes for hydrogen production by water electrolysis were compared with that of more conventional electrodes. Development of the methodology of preparing nanophase materials in a rapid, efficient and simple manner was investigated for potential application at industrial scale. Comparisons with industry standards were performed and electrodes with incorporated nanophases were characterized and evaluated for activity and durability. / South Africa

In my diploma work i focus on the production hydrogen by electrolysis of water using by electrolyzer. Especially, i concentrate on preparation electrodes for laboratory electrolyzer. I work on principles of increasing electrodes area, increasing functional surface of electrodes, by Nickel – Zinc coatings. By electroplating or chemical plating we spread microlayer of Nickel-Zinc onto electrodes made of steel plate. Then, in alkali - hydrate oxide, we will corrode Zinc components off the alloy and this is how we create pore surface of electrode. From macroscopic view, electrode has same geometrics propositions, however from microscopics view, the electrode has bigger surface area. The hydrogen production increases with unchanget sizes of electrolyzer.

Master´s thesis deals with design of oxy-hydrogen generator power supply for gas welder. Main topic of this thesis is a design of switching mode power supply, which leads to smaller dimensions and weight. Thesis includes design PCB and final measured parameters of this power supply.

The interest in hydrogen as an energy carrier is growing. The whole world is investing in development of the technology surrounding hydrogen. In general the research regarding hydrogen focuses on hydrogen as an energy carrier, either for transportation as fuel or for storage and usage at a more profitable time or in times of need. In Sweden most of the current research focus on the transportation sector. This thesis explores the other part, stored hydrogen used at a more profitable time. A biogas-plant outside Uppsala city is used as a case exploring if the investment in hydrogen production and storage in combination with a battery storage is economically feasible. A model of a battery, an electrolyser and a hydrogen storage were created in Simulink where the output is the power flow: optimised towards the highest economic profit. Then, an economic analysis is made to explore the feasibility of the investment. The results show that the investment is not feasible in 2021. If the investment cost of the hydrogen system is reduced by 60%, the maintenance costs are reduced by 20% and the profit is increased by 50% the investment becomes feasible with a payback period of 15,2 years. These changes are reasonable in the coming 10 to 20 years with hydrogen technology developing and an increasingly unstable electric grid allowing for higher compensation for frequency regulating services. / Intresset för vätgas som energibärare växer. Hela världen investerar i forskningen kring vätgas. Oftast inriktar forskningen sig på vätgas som en energibärare med två tydliga huvudfokus: som bränsle för transporter eller för lagring och att använda energin vid ett bättre tillfälle. I Sverige fokuserar den mesta forskningen på transportsektorn. Denna rapport bearbetar den andra delen, att använda vätgas för lagring och utnyttja den vid ett mer lönsamt tillfälle eller vid behovssitutioner, till exempel då elnätet blir instabilt. En biogasanläggning utanför Uppsala används som ett fall för att undersöka om investeringen i vätgasproduktion och lagring i kombination med ett batterilager är ekonomisk lönsamt. En modell av ett batteri, en elektrolysör och ett vätgaslager skapades i Simulink där utparametern är effektflödet optimerad mot ekonomisk lönsamhet. Sen undersöktes systemet ekonomiskt utifrån effektflödet för att undersöka om investeringen var lönsam. Resultatet visade att så inte var fallet: det krävs en sänkt investeringskostnad för vätgassystemet med 60%, de årliga kostnaderna behöver sjunka med 20% och den årliga vinsten behöver öka med 50% för att investeringen ska bli lönsam med en återbetalningstid på 15,2 år. Dessa förändringar kan dock ske inom de kommande 10 till 20 åren då vätgasteknologin fortsätter utvecklas samtidigt som ett allt mer instabilt elnät bidrar till möjligheten för ökad ersättning för frekvensregleringstjänster.

The main focus of this master thesis is the investigation of the anode catalysts for the Proton Exchange Membrane Water Electrolyzers (PEM-WEs). PEM-WEs play a pivotal role in the hydrogen economy concept as they allow water decomposition into oxygen and hydrogen. However, their operation requires expensive noble metal catalysts, i.e., iridium or platinum. This issue has yet to be solved to mass-produce PEM-WEs. Consequently, our main objective is to reduce the amount of iridium on the anode of PEM-WEs. We addressed this objective by two distinct approaches: morphological and chemical. With the morphological approach, plasma etching of the membrane and the magnetron sput- tering of CeO2 served to increase the membrane's active surface. Hence we improved the catalysts utilization. With the chemical approach, we focused on the catalyst itself. Thus, we replaced the pure iridium catalyst with a bimetallic iridium-ruthenium one. Therefore, the activity of the catalyst was enhanced while its price got reduced. To ex- plain and describe the catalyst's behavior, we used various electrochemical methods and surface analysis techniques. Finally, we combined both approaches to obtain one active, stable, and low-iridium-loading anode catalyst for PEM-WE.

No description available.

The electrocatalytic splitting of water is recognized to be the most sustainable and clean technology for the production of hydrogen (H₂). Unfortunately, the efficiency is seriously restricted by the sluggish kinetics of the oxygen evolution reaction (OER) at the anode. In contrast to the OER, the electrooxidation of organic compounds (EOO) is more thermodynamically and kinetically favorable. Thus, the coupling of the EOO and hydrogen evolution reaction (HER) has emerged as an alternative route, as it can greatly improve the catalytic efficiency for the production of H₂. Simultaneously, value-added organic compounds can be generated on the anode through electrooxidation upgrading. In this Minireview, we highlight the latest progress and milestones in coupling the EOO with the HER. Emphasis is focused on the design of the anode catalyst, understanding the reaction mechanism, and the construction of the electrolyzer. Moreover, challenges and prospects are offered relating to the future development of this emerging technology.