Electrochemical Engineering

Hydrogen is emerging as a pivotal energy carrier for the industrial, transportation, and power sectors due to its high energy density and potential for decarbonization. Water electrolysis is a promising, emission-free method for hydrogen production, with various electrolyzer technologies-alkaline water electrolysis (AWE), proton exchange membrane electrolysis (PEME), and anion exchange membrane electrolysis (AEME)-in active development. This review critically analyzes the advancements in electrode materials, focusing on the transition from support-based to self-supported electrodes (SSEs), which offer enhanced performance and stability under high current densities. The review emphasizes the critical shift from traditional supporting electrodes to self-supported electrodes (SSEs), which provide enhanced mechanical stability, reduce ohmic resistance, and improve overall performance at high current densities. PEM electrolyzers, for instance, generate 4.0 A/cm 2 at 2.36 V, achieving 70%-80% energy efficiency, while AEM electrolyzers perform at the same current density but at a lower voltage of 1.9 V. SSEs, such as Ru@Cu-TM cathodes, have exhibited superior performance, delivering current densities of 1.0 A/cm 2 at 1.69 V and maintaining stability over prolonged operational periods. While SSEs eliminate the limitations of traditional electrodes-such as catalyst peeling and binder instability-further research is needed to optimize their mechanical properties and scalability. Integrating advanced SSEs can significantly lower hydrogen production costs, with estimates as low as US$2.09/kg H 2 , positioning them as a pivotal solution for sustainable energy. This review provides valuable insights into the future of SSE-based electrolyzers and their role in accelerating the global transition to green hydrogen.

This study investigates the impact of CuO doping on the non-isothermal crystallisation, mechanical, and luminescence properties of 45P2O5 − (55 − x)Na2O − xCuO (where x = 0, 1, 3, and 5 mol%), prepared via a melt-quench technique. Mechanical properties are evaluated using the Makishima-Mackenzie and Rocherulle models, while crystallization kinetics are analyzed with the Kissinger and Augis-Bennett models. The substitution of Na2O with CuO weakens the glass network, with the
5 mol% CuO-doped glass (NC-5) exhibiting the lowest rigidity. Consequently, the activation energy for crystallization (Ec) decreased as CuO content increased. This is accompanied by an increase in thermal stability and a decrease in the fragility index. Furthermore, the glasses exhibited a strong greenish-blue luminescence, having the values of correlated color temperature in the range of 9404-9332 K, which makes them suitable for photonic applications.

Use of MXenes (Ti 3 C 2 T x), which belongs to the family of two-dimensional transition metal nitrides and carbides by encompassing unique combination of metallic conductivity and hydrophilicity, is receiving tremendous attention, since its discovery as energy material in 2011. Owing to its precursor selective chemical etching, and unique intrinsic characteristics, the MXene surface properties are further classified into highly chemically active compound, which further produced different surface functional groups i. e., oxygen, fluorine or hydroxyl groups. However, the role of surface functional groups doesn't not only have a significant impact onto its electrochemical and hydrophilic characteristics (i. e., ion adsorption/diffusion), but also imparting a noteworthy effect onto its conductivity, work function, electronic structure and properties. Henceforth, such kind of inherent chemical nature, robust electrochemistry and high hydrophilicity ultimately increasing the MXene application as a most propitious material for [a] A

Regenerative fuel cells and the phenomenon of cell reversal (CR) necessitate creating robust catalyst layers for consistent performance in fuel cells. This research used in situ Raman spectroscopy to observe molecular alterations on carbon nanotube-supported platinum catalysts (Pt/CNT) during ethanol oxidation. Following a CR event simulation, the ethanol oxidation efficiency on Pt/CNT was amplified 2.8 times after high-potential scanning but reverted to its initial efficiency after 100 cycles. The adsorbed *CO 2 -species on Pt/CNT was pivotal for initiating ethanol oxidation, with the rate assessed through Raman analysis. In addition to water electrolysis, the carbon substrate was degraded. This study sheds light on the mechanisms behind catalyst degradation, steering the creation of more advanced catalysts.

BACKGROUND: A batch electrochemical reactor with a rotating cylinder electrode is analysed for the transformation of sulphur dioxide into either sulphuric acid or colloidal sulphur. RESULTS: Potentiostatic experiments carried out at 30 °C and 500 rpm with 5 g L -1 SO 2 in 0.5 mol L -1 H 2 SO 4 conclude that -0.7 V represents an appropriate potential for the sulphur production at a 316L stainless steel cathode. The figures of merit were: 0.15 kg m -3 h -1 space time yield and 39.7 kWh kg -1 for specific energy consumption. Galvanostatic experiments at 30 °C and 1000 rpm with three-dimensional electrodes identify graphite felt as a promising anodic material. Using a gas phase of 5% SO 2 in nitrogen and 0.5 mol L -1 H 2 SO 4 as supporting electrolyte, a macrokinetic current density of 100 mA cm -2 represents an appropriate value, being the space time yield 7.58 kg m -3 h -1 with 2.86 kWh kg -1 specific energy consumption. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record.

Polymer Electrolyte Membrane Fuel Cell (PEMFC), an electrochemical power generating technology, uses a precious metal Platinum (Pt) catalyst for Oxygen Reduction Reaction (ORR), which is a major hindrance in its commercialization. Using a non-precious group metal (NPGM) instead of Pt will reduces the cost of PEMFCs. Herein MnO2 carbon nanotubes (CNTs) were synthesized by impregnating the transition metal in large surface carbonaceous material CNTs by hydrothermal synthesis techniques. To enhance the catalytic reaction and increase the volumetric current density, the sample was pyrolyzed at 800 0C temperature under nitrogen atmosphere. During pyrolysis, the nitrogen was also doped in the framework of carbonaceous materials. The materials were then treated with acid, removing the unreacted metals and adding oxygen functional group to the CNT framework due to which the activity of the catalyst is amplified. The catalysts have been characterized by scanning electron microscope (SEM), X-...

Metal-supported graphene nanocomposites with single atoms or small clusters are of interest for various catalytic processes, including applications in batteries, fuel cells, water electrolysis, and chemical synthesis. Typically, graphene oxide is reduced in the presence of metal salts to produce metal-graphene nanocomposites. However, graphene itself has reductive properties and can react with metal ions in higher oxidation states in a suitable solvent. While direct reactions (dip and coat or wet coating) with metal salts have been described several times, less is known about the kinetics. This study investigates the reaction of suspended graphene nanoplatelets (GNP) in aerated water with the chlorocomplexes of gold (III), iridium (IV), platinum (IV), and palladium (II) to form nanocomposites covered with single atoms and small clusters. The maximum metal loading ranges from 3.3 mass% for palladium to 44 mass% for gold, increasing with redox potential. At high redox potentials, such as those of Ir (IV) and Au (III), the reactions follow pseudo-first order kinetics. In contrast, at lower potentials, such as those of Pt (IV) and Pd (II), the reaction adhere to pseudo-second order. This data enable kinetically controlled metal coating of the GNP. In contrast to the use of a reducing agent, gold, platinum, and palladium are present on the GNP in different oxidation states, which can be specifically modified, as shown for platinum-coated GNP. Iridium (IV) has been deposited as anhydrous and hydrated iridium (IV) oxide. The nanocomposites have great potential as single-atom catalysts. The described process can be transferred to other transition metals and is sustainable because the reaction media can be recycled.

The composition of matter comprising Ga(Sb x )N 1 _ x where x = 0.01 to 0.06 is characterized by a band gap between 2.4 and 1.7 eV. A semiconductor device includes a semiconduc tor layer of that composition. A photoelectric cell includes that semiconductor device. • H 2 evolution potential • 0 2 evolution potential * cited by examiner

The disinfection of water (including wastewater) plays a vital role in providing safe drinking water and decontaminating fluids released from medical facilities and pharmaceutical production plants. The reduction in microbial numbers, and the targeted elimination of pathogens, is combined with the removal of unwanted impurities, including antimicrobials. This is an important consideration as trace amounts of antibiotics in wastewater may increase microbial resistance, leading to the development of antibiotic-resistant bacteria.

For many years, the traditional route has been by chemical disinfectants, primarily the application of oxidants such as free chlorine, peracetic acid, chlorine dioxide, chloramines, ozone and ultraviolet radiatio. These kill microorganisms through protein and enzyme denaturation and DNA destruction.

Attention is increasingly being paid to electrochemical disinfection and photocatalytic disinfection to minimise pollution and to meet the safety requirements of wastewater reuse. This is a topic that pharmaceutical and healthcare organisations need to be mindful of. These alternative forms of disinfection for water treatment are examined in this article.

Sandle, T. (2025) Water disinfection: Innovations in chemistry and light, RSSL Life Science Insights, 2nd April 2025: https://www.rssl.com/insights/life-science-pharmaceuticals/water-disinfection-innovations-in-chemistry-and-light/

This work reports the most important parameters during brine electrolysis. Herein, cells design was built and optimized for chlorine and hydrogen production using graphite electrodes. These electrodes were from recycling batteries. Also, a series of experiments were conducted in order to test the effect of the space between the electrodes on minimal cell voltage. The results clearly show that when the space between the electrodes decreases, the cell voltage decreases too. Thus, the optimum value was 0.75 cm and the minimum cell voltage with this gaps was 2.83V. Likewise, the effects of some operating parameters like electrolytes concentration and temperature on conductivity were studied. The optimum conditions for brine electrolysis were 320 g.L -1 NaCl (pH=2), 24% NaOH, T = 80°C. To express the efficiency of electrochemical reactions, two types of current efficiency were calculated based on Faraday’s law of electrolysis. The current efficiencies were 81% and 83% respectively for ch...

Herein we report on the synthesis, characterization and catalytic evaluation of cobalt (Co) and tin (Sn) oxide catalysts synthesized via the sol-gel approach. Preliminary characterization using nitrogen sorption measurements show the materials as mesoporous with relatively high surface area. The catalyst with the least amount of Co had the highest surface area (146 m 2 /g) compared to the catalysts with the highest amount of Co. Furthermore, temperature-programmed reduction (H 2 -TPR) was used to study the redox properties of the catalysts. The H 2 -TPR analysis revealed that the catalysts are only reduced at relatively high temperatures (> 300 °C). While the temperature-programmed desorption using ammonia (NH 3 -TPD) and carbon dioxide (CO 2 -TPD) results suggest that the total amount of acidic and basic sites is the function of different amounts of metal content in the catalytic materials. The catalyst with the least amount of Co appeared to have the highest number of acidic sites compared to other catalysts. Evaluation of the catalytic activity was studied using oxidation of morin as model reaction. The catalyst with the least amount of Co, (Co 0.3 Sn 0.7 O x ) appeared to be the most active catalyst.

The development of active hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) catalysts for use in anion exchange membrane fuel cells (AEMFCs), which are free from platinum group metals (PGMs), is expected to bring this technology one step closer to commercial applications. This paper reports our recent progress developing HOR Pt-free and PGM-free catalysts (Pd/CeO2 and NiCo/C, respectively), and ORR PGM-free Co3O4 for AEMFCs. The catalysts were prepared by different synthesis techniques and characterized by both physical-chemical and electrochemical methods. A hydrothermally synthesized Co3O4 + C composite ORR catalyst used in combination with Pt/C as HOR catalyst shows good H2/O2 AEMFC performance (peak power density of ~388 mW cm−2), while the same catalyst coupled with our flame spray pyrolysis synthesised Pd/CeO2 anode catalysts reaches peak power densities of ~309 mW cm−2. Changing the anode to nanostructured NiCo/C catalyst, the performance is significantly ...

Electrocoagulation (EC) can be an efficient alternative to existing water and wastewater treatment methods due to its eco-friendly nature, low footprint, and facile operation. However, the electrodes applied in the EC process suffer from passivation or fouling, an issue resulting from the buildup of poorly conducting materials on the electrode surface. Indeed, such passivation gives rise to various operational problems and restricts the practical implementation of EC on a large scale. Therefore, it has been suggested that using pulsed direct current (PDC), alternating pulse current (APC), and sinusoidal alternating current (AC) waveforms in EC as alternatives to conventional direct current (DC) can help mitigate passivation and alleviate its associated detrimental effects. This paper presents a critical review of the impact of the current waveform on the EC process towards the capabilities of the PDC, APC, and AC waveforms in de-passivation and performance enhancement while comparing them to the conventional DC. Additionally, current waveform parameters influencing the surface passivation of electrodes and process efficiency are elaborately discussed. Meanwhile, the performance of the EC process is evaluated under different current waveforms based on pollutant removal efficiency, energy consumption, electrode usage, sludge production, and operating cost. The proper current waveforms for treating various water and wastewater matrices are also explained. Finally, concluding remarks and outlooks for future research are provided.

The anode effect can occur during neodymium and didymium oxide electrowinning, causing a surge in the electrochemical cell voltage, interrupting the process, and increasing the greenhouse gas emissions. In this work, we develop a mathematical model, based on the mass balance of gas bubbles evolving from the anode, to understand the influence of some process parameters on the anode effect. The anode effect occurs due to bubble coverage and limitations on the mass transfer of the oxide species. Variables such as current density, oxide content, viscosity, and electrolyte composition play an important role in the anodic process. Finally, we propose a mechanism for the occurrence of the anode effect during Nd or Di (Nd-Pr) oxide electrolytic reduction based on models used in aluminum electrolysis.

In this paper, the nature of the species formed in the electrochemical interactions between a polycrystalline platinum surface and cyanide and copper-cyanide species in alkaline solution (pH 13) has been investigated by combining cyclic voltammetry with in situ FTIR spectroscopy. This study was performed because electrochemical reactors for the treatment of cyanide-containing industrial wastewaters have been shown to achieve viable destruction rates when copper ions are present in the alkaline solution through the formation of copper oxide films [1-3]. It has been found that the complexation of cyanide ions by copper species hinders the adsorption of the anion at the electrode, thus avoiding the characteristic electrode poisoning by CO that occurs in the absence of soluble copper species. Conversely, soluble copper-cyanide complexes can be electrooxidized at the platinum surface through the formation of cyanate species as intermediate, and of HCOOH and NO as end products. The addition of copper species to the electrolyte also facilitates this route for cyanide oxidation to occur at higher rates without poisoning the platinum electrode.

INTRODUCTION Nanofluids are nanoparticle-in-liquid suspensions (typically of up to 5% concentration, for nanoparticles between 1 to 100 nm in size). They are studied for their enhanced thermal transport properties, and mainly as potential alternatives to ordinary cooling fluids. Nanofluids are promising as coolants for critical-cooling systems, as in compact heat exchangers; these and other potential uses of nanofluids, are discussed in [1]. However, many practical concerns are unknown regarding nanofluid tribological effects on cooling system materials, as wear and erosion, and there are no standard methods to test such pehonomena. The authors have designed and developed two new types of erosion-test instruments to test nanofluid wear-effects on material surfaces.

Electro-osmosis is a phenomenon describing the motion of liquid adjacent to a charged surface under the influence of an electric field. Electro-osmosis is considered as an efficient soft soil improvement technique. In this study, series of laboratory tests were performed utilizing graphite and stainless steel electrodes under three levels of voltage gradients for 28 days using the soil from north of Iran to investigate the effect of various parameters on electro-osmotic and geotechnical properties. Moreover, the microstructure and chemical analyses of the soil before and after treatment gave an in-depth perspective to underlying mechanism of this process. Water drainage which has the most important effect on consolidation of soils, terminated after a few days. The termination time for stainless steel is smaller than graphite and the whole drained water volume is larger in case of stainless steel compared to graphite. The strength around the anode is larger than that of the cathode zone and the stainless steel electrode induced larger strength than the graphite electrode. The SEM images exhibited the agglomeration of the soil after electro-osmosis treatment, and some precipitation was also identified, which was attributed to iron based compounds. Chemical analysis illustrated that the concentration of calcium ions decreased around the anode and increased near the cathode while Fe and Al amount did not change significantly, implying the ion exchange and ion migration due to the electro-osmosis process. Additionally, the stainless steel electrode introduced iron and chrome ions to the soil, which affected structure and chemical distribution of the ions.

In response to the increasing global water demand and the pressing environmental challenges posed by climate change, the development of advanced wastewater treatment processes has become essential. This study introduces novel electrochemical technologies and examines the scalability of industrial-scale electrooxidation (EO) methods for wastewater treatment, focusing on simplifying processes and reducing operational costs. Focusing on the effective removal of key nutrients, specifically nitrogen and phosphorus, from wastewater, this review highlights recent advancements in electrode materials and innovative designs, such as high-performance metal oxides and carbon-based electrodes, that enhance efficiency and sustainability. Additionally, a comprehensive discussion covers a range of electrochemical methods, including electrocoagulation and electrooxidation, each evaluated for their effectiveness in nutrient removal. Unlike previous studies, this review not only examines nutrient removal efficiency, but also assesses the industrial applicability of these technologies through case studies, demonstrating their potential in municipal and industrial wastewater contexts. By advancing durable and cost-effective electrode materials, this study emphasizes the potential of electrochemical wastewater treatment technologies to address global water quality issues and promote environmental sustainability. Future research directions are identified with a focus on overcoming current limitations, such as high operational costs and electrode degradation, and positioning electrochemical treatment as a promising solution for sustainable water resource management on a larger scale.

Metal-supported graphene nanocomposites with single atoms or small clusters are of interest for various catalytic processes, including applications in batteries, fuel cells, water electrolysis, and chemical synthesis. Typically, graphene oxide is reduced in the presence of metal salts to produce metal-graphene nanocomposites. However, graphene itself has reductive properties and can react with metal ions in higher oxidation states in a suitable solvent. While direct reactions (dip and coat or wet coating) with metal salts have been described several times, less is known about the kinetics.

Tailoring a reduced graphene oxide-Cu-Cu 2 O (rGO-Cu-Cu 2 O) as a three-dimensional (3D) integrated catalytic system via an in-situ potential-controlled electrodeposition approach is a feasible pathway to boost methanol oxidation reaction (MOR) for direct methanol fuel cell. The enhancement in catalytic functionality and performances is due to the synergistic interaction between the in-situ electroreduced graphene oxide (rGO) and copper metal ions over it. The sequential and synergistic effect of the co-deposition potential, optimized time, and probable corrosion-promotion effect (formation of a galvanic cell between rGO and copper due to entrapped dissolved oxygen) is believed to be responsible for the structural growth of as-developed 3D catalytic systems. The MOR results suggest that the composite material deposited at the higher cathodic deposition potential (-1.2 V vs SCE), i.e., rGO-Cu (c) featured the remarkable lowest onset oxidation potential (i.e., +0.37 V), peak potential (i.e., +0.73 V), peak current density (135.76 mAcm − 2), potentiostatic durability at +0.6 V after 3.5 h (~65.85 mAcm − 2) and outstanding cyclic stability (~97.7 % current retention after 500 cycles), which is superior to the other modified composite electrodes. The enhanced performances are due to the effective dissociative adsorption of methanol from the available active catalytic site's and the presence of hydroxyl groups which has probably improved the oxidation of adsorbed intermediates from the surface. Further, Fouriertransform infrared (FT-IR) experiments revealed that formate as an active intermediate is being generated on all three rGO-Cu-Cu 2 O modified electrodes and follows the non-CO reaction pathway for direct oxidation of methanol.

In this paper, the nature of the species formed in the electrochemical interactions between a polycrystalline platinum surface and cyanide and copper-cyanide species in alkaline solution (pH 13) has been investigated by combining cyclic voltammetry with in situ FTIR spectroscopy. This study was performed because electrochemical reactors for the treatment of cyanide-containing industrial wastewaters have been shown to achieve viable destruction rates when copper ions are present in the alkaline solution through the formation of copper oxide films [1-3]. It has been found that the complexation of cyanide ions by copper species hinders the adsorption of the anion at the electrode, thus avoiding the characteristic electrode poisoning by CO that occurs in the absence of soluble copper species. Conversely, soluble copper-cyanide complexes can be electrooxidized at the platinum surface through the formation of cyanate species as intermediate, and of HCOOH and NO as end products. The addition of copper species to the electrolyte also facilitates this route for cyanide oxidation to occur at higher rates without poisoning the platinum electrode.

Rotating cylinder electrode (RCE) is used. in weight loss technique , the salinity is 200000 p.p.m, temperatures are (30,5060,7080Co). the velocity of (RCE) are (500,1500,3000 r.p.m). the water cut (30% , 50%). The corrosion rate of carbon steel increase with increasing rotating cylinder velocity. In single phase flow, an increase im rotational velocity from 500 to 1500 r.p.m, the corrosion rate increase from 6.88258 mm/y to 10.11563 mm/y respectively.

The purpose of this research is to explore into the impacts of H + ion implantation on Al/ LiCo 3 O 4 /ITO (MIS) thin films employing the sprayed pyrolysis method. The discharged and recharged specimens were characterized using XRD, EDAX, and SEM techniques. Using LiCo 3 O 4 CV curves in KOH solution at various scan speeds, the electrochemical behavior was investigated. Li + and H + ions from a KOH solution underwent a reversible insertion into the diffusion coefficient values of LiCo 3 O 4 particles. Increased protonic conductivity and a higher diffusion coefficient value of 3.55x10 À8 cm 2 /S with a scan rate of 100 mV/S are the results of the intercalation of lithium with the cobalt oxide LiCo 3 O 4 and this implantation affects the possible causes of the observed changes in the properties of lithium cobalt oxides. The spray pyrolysis method's process parameters have a major impact on the H + implantation film's characteristics. As a result, they have been enhanced to produce high-quality LiCo 3 O 4 films with excellent electrical conductivity and transparency.

Vanadium Redox Flow Batteries (VRFB) can be used as energy storage device, for example to account for wind or solar power fluctuations. In VRFBs charge is stored in two tanks containing two different vanadium solutions. This approach decouples the storage capacity and the power supply which is dependent only on the number and size of the cells [1]. A control specific model of a VRFB is proposed, which captures the essential dynamic properties of the battery while ignoring all fluid mechanical elements. The model of the battery is a nonlinear DAE comprising a differential equation for the state of charge SoC and algebraic equations based on the Butler-Volmer equation for the current I and the voltage U, the power P = U∙I being set by the operator. The battery typically operates in constant power mode, but the control system limits its operating range by switching to a constant voltage when upper or lower voltage thresholds are reached. In addition, this VRFB contains a secondary flow...

pour son accueil au début de ces trois années de thèse, puis à Pierre GROS qui a pris la relève en qualité de directeur adjoint. Je souhaiterai remercier le fameux professeur Théodore TZEDAKIS qui m'a fait le plaisir de présider ce jury de thèse, ainsi que Eric CHAINET et Virginie LAIR qui ont acceptés de juger ce travail. J'associe à ces remerciements Isabelle CRASSOUS ainsi que Jérôme ROCHE pour leur participation au jury. Je tiens à remercier chaleureusement celui qui à probablement perdu le plus de cheveux lors de ces trois dernières années, mon directeur de thèse Pierre CHAMELOT dit « Pedro ». Milles mercis pour ta bienveillance, ton soutien et ta bonne humeur qui m'ont poussé à m'accrocher même dans les moments difficiles de cette thèse. Tu m'as transmis tout le nécessaire pour franchir cette épreuve, des notions d'électrochimie, en passant par la fabrication de pièces à l'aide d'un tour ou à la réalisation de bons rhums arrangés (même si les miens font encore pale figure devant les tiens). Je tiens également à adresser un énorme merci à mon co-directeur de thèse, Mathieu GIBILARO. Merci pour ton écoute, tes nombreux conseils, ta grande disponibilité au quotidien et tes talents de « grammar nazi ». Merci de m'avoir fais découvrir le monde exotique des Sels Fondus lors de mon stage de L3. Je garderai de très bon souvenir des soirées au Botaniste ou au Black-lion. A ces remerciements j'aimerai associer Laurent MASSOT qui a grandement participé à l'encadrement de cette thèse. Merci pour toute l'aide que tu as apporté aussi bien scientifique que technique. Travailler avec toi c'est comme utiliser un « cheat-code » dans un jeu vidéo, tu trouves en un instant une solution à tous les problèmes sur lesquels on but sans cesse. Merci également d'avoir su trouver les bons mots quand ça n'aller plus et que le moral flanché, tu m'as permis de me remettre sur les rails et de ne rien lâcher. Merci infiniment à vous trois, je suis entré en thèse en étant en dépression mais j'en pars le coeur léger et avec le sourire. Si j'en suis là aujourd'hui c'est en grande partie grâce à vous trois. Un grand merci à Christelle, Pierre R., Patric et Sébastien qui m'ont assisté techniquement pour mettre en place des manips, usiner des pièces fragiles ou encore programmer le système pietzo. Je voudrais ensuite remercier l'ensemble des personnes avec qui j'ai pu partager convivialement le bureau lors de ces trois ans et notamment Julien membre du duo de choc Rox et Rouky ! Merci pour ta précieuse amitié et ton grand soutien ! Merci pour m'avoir fait l'immense plaisir de venir depuis Dijon pour assister à ma soutenance. Je garderai d'excellent souvenir de nos aventures que ce soit en Andorre, à Lombrive, à Cabrespine, au tranchoir ou même au Kraken ! De ta grande sagesse je retiendrai surtout comment écrire le prénom willem ouillem wouilhem m'orienter avec l'étoile polaire. Remerciements Merci également à Shérif et à Maarten qui m'ont accompagné sur la fin de la thèse et ont amené un peu de vie dans le bureau qui était devenu bien trop silencieux et morose. Bon courage pour vos thèses les gars ! Je remercie aussi l'ensemble des stagiaires (surtout Anaïs qui a dû supporter mon encadrement), des doctorants et post-doctorants avec qui j'ai pu partager de bons moments au quotidien. Merci notamment Cécilia, Lisa et Cholé pour les pauses thé, Mélissa pour ses cafés incroyables, ainsi que Nabil et Charaf pour nos fous rires et l'humour politiquement incorrect que nous partageons. Merci à l'ensemble des membres du laboratoire pour tous ces agréables moments d'échanges qu'ils soient scientifiques ou non. Merci à la famille F. sans qui je n'aurais probablement jamais repris mes études. Merci à tout mes amis qui m'ont soutenu lors de cette épreuve et m'ont fait le plaisir de venir ou de suivre la soutenance : Marc, Sylvain, Christophe, Agnès, Quentin, Nina, Catherine et son clone Caroline et bien d'autres. J'aimerai également remercier du fond du coeur des amis très chère qui suivent mon parcours depuis 10 ans maintenant : mes anciens camarades d'IUT : Elodie et Seb. Merci à toi Elodie de m'avoir fais l'honneur d'être ton témoin de mariage et merci Seb d'avoir fais le déplacement depuis Renne pour assister à la soutenance. Un immense merci à celles que je considère comme mes petites soeurs Solyane et Txori (et oui ce sont des vrais prénoms). Merci à vous deux pour votre soutien et votre présence, vous compter énormément pour moi. Un énorme merci à Thomas avec qui nous partageons de nombreux délire et activité depuis le collège. Merci d'avoir été là dans les bons et moins bons moments de la vie, merci de m'avoir soutenu, supporté et épaulé comme tu l'as fait durant tout ce temps. Milles merci également à mes parents qui m'ont toujours soutenu dans mes choix ainsi qu'à mon frère qui bien que peu présent est un complice incroyable. Enfin, merci à toi Tuire (encore un prénom chelou) pour ton soutient qui m'a grandement aidé à tenir

Most of plasmas created in laboratories for experiments in domains such as inertial confinement fusion are non-LTE plasmas. The modeling of the atomic kinetics of these plasmas is crucial to understand the radiative properties of these environments. There is a strong demand for experiments in which the plasma is characterized by independent X-ray spectroscopy diagnostics. Thus the development of new diagnostics for these experiments is also a major stake.

This study was designed to compare the effectiveness of Aluminium (Al) and Iron (Fe) as electrodes to reduce the polluting nature of Palm Oil Mill Effluent (POME) and simultaneous hydrogen production using electrocoagulation (EC). Electrocoagulation of raw POME and anaerobically pretreated POME was performed using Direct Current (DC) electricity of 2.0, 3.0, and 4.0 volts in a reactor volume of 20 liters. The results of raw POME treatment reveal that the chemical oxygen demand (COD) and turbidity was decreased around 57.66% and 62.5%, respectively, using Al electrode. However, the use of iron electrodes could reduce the COD and turbidity of raw POME about 35.3% and 43.10%, respectively. The reduction in polluting factors of the raw POME was accompanied with the production of 42% and 22.8% of hydrogen gas concentration using Al and Fe electrodes, respectively. On the other hand, the results of Electrocoagulation of POME which was pretreated in anaerobic pond show that the COD was dec...

Electrocoagulation process using high current intensity to treat palm oil mill effluent (POME) was investigated in this study. Various operating parameters such as electrolysis time, interelectrode distance and initial pH were carried out to determine the efficient process condition on the removal of chemical oxygen demand (COD), biological oxygen demand (BOD) and suspended solids (SS). The highest treatment was achieved at 50 min with the removal efficiencies for COD, BOD and SS obtained as 85%, 83%, and 84%, respectively. More than 50 min treatment showed the fluctuated trends of removal efficiencies which can be considered insignificant. The application of higher current resulted in higher removals of organics while the gas bubbles also assisted in removing the pollutant particles by floatation. In an inter-electrode distance study, the removal efficiency decreased when inter-electrode distance was either higher or lower than 10 mm due to the increase of solution resistance and the decrease of anode active surface area. In initial pH study, it was found that high removal efficiencies were achieved in slightly acidic POME sample rather than in neutral or basic condition. An electrocoagulation process by using the optimum operating parameters was able to remove COD, BOD and SS up to 95%, 94% and 96% respectively. The experimental results confirm that application of high current intensity in electrocoagulation provided high treatment efficiency at a reduced reaction time.

The standard Rotating Cage (RC) is a very useful comparative method for screening materials, crude oils and corrosion inhibitors. Thinking of reduce costs and time expended in laboratory tests, mainly to evaluate inhibitors by RC and electrochemical techniques tests; we developed an Electrochemical Rotating Cage Autoclave assembly (ERCA). Herein we present the ERCA system and the electrochemical response validation using a well-known redox system. Additionally, we compared the impedance diagrams of bare carbon steel in a 0.16% NaCl brine at 500 RPM with 1 and 100 bar of CO2. Preliminary results of inhibitors electrochemical evaluation during the RC test showed the film formation and growth. With ERCA is possible to use electrochemical techniques to monitor the corrosion process or inhibitor action during the RC laboratory test. Electrochemical results can be compared with standard weight loss performed after the test using the standard RC samples tested in the same batch. The aim is...

Modified polymer precursor method was used to synthesized Tungsten carbide (WC). The formation of WC was ascertained through X-ray Diffraction (XRD) and Thermo Gravimetry Analysis (TGA). The WC electrode was synthesized over 316 stainless steel to evaluate electrical conductivity by four probe method and electrochemical performance through cyclic voltammetry (CV). The CV curves of WC electrode were found in the potential span of -1.5 to 0.0V in KOH (1.0M). The WC electrode exhibit band gap of 0.64 eV and good cyclic stability over 200 cycles.

Modified polymer precursor method was used to synthesized Tungsten carbide (WC). The formation of WC was ascertained through X-ray Diffraction (XRD) and Thermo Gravimetry Analysis (TGA). The WC electrode was synthesized over 316 stainless steel to evaluate electrical conductivity by four probe method and electrochemical performance through cyclic voltammetry (CV). The CV curves of WC electrode were found in the potential span of-1.5 to 0.0V in KOH (1.0M). The WC electrode exhibit band gap of 0.64 eV and good cyclic stability over 200 cycles.

Nanofluids are enhanced alternatives to ordinary cooling fluids, because these nano-size-powder suspensions show superior heat transfer properties. But there is very little understanding of their wear, erosion and corrosion on surfaces. Because there are no standard tests or instruments for nanofluid tribological effects [2] the authors developed two test-rigs and tested multiple surface-change assessment techniques. Research is presented on a nanofluid (2%-alumina-nanopowder in water, and in water/ethylene glycol solutions) tested on specimens of typical heat-exchanger materials (aluminum and copper. The enhanced surface modifications (when same test is conducted with alumina-nanofluids as compared to the base fluids) were assessed by roughness measurements, by weighing of removed-material, and by opticalmicroscopy. The obtained results show the suitability of the new testing and assessment techniques and they suggest that nanofluids may lead to substantial erosion-corrosion effect...

Designing an active and reliable electrocatalyst is the urgent need for the desirable improvement in direct methanol fuel cells (DMFCs). In recent time, binary metal oxides have shown much attention as possible electrocatalysts for the future DMFCs. Herein, we have reported direct growth of 3D-CuCo 2 O 4 on Nickel foam (NF) by hydrothermal route for electrochemical methanol oxidation. The electrochemical performance was examined by cyclic voltammetry (CV), chronoamperommetry (CA) and electrochemical impedance spectroscopy (EIS) techniques. Electrochemical analysis of 3D-CuCo 2 O 4 exhibits high current density of 112 A g − 1 at scan rate of 10 mV s − 1 and retains 91% of initial current density after 1000 C V cycles. The high electrocatalytic activity of mesoporous 3D-CuCo 2 O 4 is mainly ascribed to the synergetic effect of bimetallic element (Cu and Co), high surface area and enhanced charge-transfer because of direct growth of catalyst on NF. The present synthesis strategy and use of spinel oxides can offer promising feature for the development of non-precious catalysts for DMFCs.

Transition metal oxides have attracted attention as promising electrode materials for energy storage and conversion devices with high electrochemical activity and stability. In this study, a simple and cost‐effective solvothermal synthesis of rectangular 3D CuCo2O4 hollow tubes have been developed for methanol electro‐oxidation application. Electrochemical analysis shows that CuCo2O4 hollow tubes exhibit superior electrochemical performance in terms of current density and cycling stability, with 75 mA cm−2 and 90 % retention rate after 1000 cycles, respectively. The high electrochemical performances are mainly due to the morphological structure of CuCo2O4 hollow tubes, which possess high surface area and porosity, resulting to a faster electron‐ion transfer, enhanced reactivity and stability. Given that the synthesis of CuCo2O4 hollow tubes involve a facile and cost‐effective technique, the present approach, thus, opens a new era to novel materials for large‐scale processes in diffe...

The effect of flow on corrosion behaviour of carbon steel under intermittent oil/water wetting was investigated by a newly-modified "alternate wetting cell", combining with the use of potentiostatic polarisation, in-situ visualisation, contact angle measurements and scanning electron microscopy (SEM). The oil/water wetting time was determined by the formation of a thin oil/water film on the electrode surface after the transition of immersion state. A short alternate oil/water immersion period and low flow velocity can increase the ratio (oil to water wetting time) and efficiently mitigate the corrosion, proposing a logistic regression tendency between corrosion mitigation efficiency and oil/water wetting time.