Electrolysis Technique Research Articles

Deformable airfoil using hybrid of mixed integration electrolysis and fluids chemical reaction (HEFR) artificial muscle technique

In this research, by inspiration of natural myosin motion in artificial muscle contraction, a new method for changing the thickness of an airfoil has been proposed by hybrid of mixed integration electrolysis module and chemical reaction (HEFR) of sodium bicarbonate (NaHCO3 (s)) and acetic acid (CH3COOH (l)). The mentioned method has the ability to create pressure in the fluid in a short time and fast transfer without delay due to the integration of the method in the fluid transfer tube to soft sealed skin. With soft sealed skin swelling and movement of solid skeletal structure, the force is transmitted to the desired mechanism. First, for a single of soft skin and solid structure, remarkable displacement over time in the various loading condition (by the inflation tester) has been investigated. It is shown that the proposed mechanism is capable of moving 246 g during 3 s with total mechanism weight of 10 g. In the following, the mechanism is developed into a symmetrical rhombus (set of soft skin-solid structure) with the ability to contract and expand to provide variable airfoil thickness. The proposed mechanism has the ability to move in the horizontal and vertical axis (expansion and contraction) in lower than 5 s by applying the HEFR technique. Such a mechanism is mounted on a symmetrical airfoil and has the ability to change the airfoil thickness with the appropriate response time. The proposed mechanism can be used in various industrial applications such as robotics.

Effects of Doped N, B, P, and S Atoms on Graphene toward Oxygen Evolution Reactions.

Molecular oxygen and hydrogen can be obtained from the water-splitting process through the electrolysis technique. However, harnessing energy is very challenging in this way due to the involvement of the 4e– reaction pathway, which is associated with a substantial amount of reaction barrier. After the report of the first N-doped graphene acting as an oxygen reduction reaction catalyst, the scientific community set out on exploring more reliable doping materials, better material engineering techniques, and developing computational models to explain the interfacial reactions. In this study, we modeled the graphene surface with four different nonmetal doping atoms N, B, P, and S individually by replacing a carbon atom from one of the graphitic positions. We report the mechanism of the complete catalytic cycle for each of the doped surfaces by the doping atom. The energy barriers for individual steps were explored using the biased first-principles molecular dynamics simulations to overcome the high reaction barrier. We explain the active sites and provide a comparison between the activation energy obtained by the application of two computational methods. Observing the rate-determining step, that is, oxo–oxo bond formation, S-doped graphene is the most effective. In contrast, N-doped graphene seems to be the least useful for oxygen evolution catalysis compared to the undoped graphene surface. B-doped graphene and P-doped graphene have an equivalent impact on the catalytic cycle.

Study the Effect of Annealing on the Structural Properties of Zinc Oxide Films by Electrolysis Technique

Zinc oxide films (ZnO) are prepared by an electrolysis technique and without vacuum and then annealed atvarious temperatures (300,400,500)OC for an hour. The structural analysis performed by X-Ray diffraction (XRD) shows,dominant orientation of this films is plane (101), has a hexagonal structure and polycrystalline pattern and it was is found that the crystal size increases(24,29) nm at annealing temperatures (300, 400)° C, but the crystal size decreases to (20 nm) at annealing temperature (500 ° C). As the results of a surface nature study of these films showed by examining the atomic force microscope (AFM), the grain size increases from (60.79 to 88.11) nm, and the surface roughness increases from (1.99 to 2.34) nm when increasing annealing temperatures is (300,400,500)°C, respectively.

Biodiesel production via esterification of oleic acid as a representative of free fatty acid using electrolysis technique as a novel approach: Non-catalytic and catalytic conversion

In the present study, production of biodiesel from biomass containing free fatty acids has been evaluated through electrolysis method as a novel efficient technique, in absence and presence of alkaline and acidic catalysts at mild operating condition. The impact of operating parameters such as voltage (10−30 V/cm), reaction time (1−3 h), methanol to oil molar ratio (10:1−40:1), acetone to methanol molar ratio (0:1−0.5:1), NaCl concentration (0−0.045 M) and catalyst type and loading on the process performance have been investigated in term of biodiesel production yield. The achieved results indicate that the biodiesel production yield using electrolysis method is about 42 % at voltage of 20 V/cm, reaction time of 2 h, NaCl concentration of 0.015 M, methanol to oil molar ratio of 20:1, acetone to methanol molar ratio of 0.25:1 and without presence of catalyst, whereas it is improved to 52 % and 95 % in the presence of 5.6 wt.% of KOH and 13 wt.% of H2SO4 as catalyst, respectively. The determined physicochemical properties of the synthesized biodiesel via electrolysis method incorporating density, kinematic viscosity, cetane index, Iodine value and cloud point properties satisfy the main fuel standard criteria. The cetane index of synthesized biodiesel using electrolysis method is 57.3.

Synthesis and characterization of titania/graphene nanocomposite for application in photocatalysis

Titanium dioxide has been extensively investigated as a photocatalyst for water purification, presenting limitations such as recombination of electron-hole pairs generated by photons. The titania / graphene nanocomposites are promising materials to overcome these limitations due to the high specific area of graphene and unique electronic properties. In this work, an anatase-graphene nanocomposite was synthesized by a simple mixture assisted by ultrasound. Graphene was obtained by electrochemical exfoliation of graphite using the electrolysis technique. On the other hand, anatase was synthesized using the sol gel method. The obtained graphene, anatase and the nanocomposite material, were characterized with the X-ray diffraction technique (DRX), scanning electron microscopy (MEB) and transmission electron microscopy (MET). Using Raman spectroscopy, it was possible to verify that the graphite exfoliated correctly producing few layer-graphene. The lamellar nano-structure of the exfoliated graphite has crystallographic planes characteristic of graphite, graphene and graphene oxide. The presence of the anatase phase is shown in the diffraction spectrum of titania. The images obtained with SEM and TEM of the graphene sample show a layered lamellar structure and the TiO2 images show agglomerates of ellipsoidal nanoparticles. Obtained titania nanoparticles have a size of about 6 nm. Band gap value for such extremely low particle size nanocomposite is around 3.6 eV and presumably corresponds to the TiO2 (anatase) phase that completely surrounds the graphene. A nanocomposite model based on HRTEM observations is proposed. Considering the graphene electrical properties and the photocatalytic properties of TiO2, this nanocomposite promises to have applications in photocatalysis.

Cubic γ-Al2O3 coating modified graphite powder

Poor wettability and oxidation resistance have limited the application of graphite powder. A key to the problem is the surface modification. A ceramic coating was synthesized in this manuscript by the non-electrode plasma electrolysis technique for the purpose. The result showed that a cubic γ-Al2O3 coating was deposited on the graphite with a thickness of ~50 nm. The γ-Al2O3 coating significantly improved the oxidation resistance of the graphite powder and wettability, evidenced by ~80 °C the obvious increase of the initial oxidation temperature and ~50% improvement in wettability. We believe the technology will promote the development of powder surface modification technology and the application of the graphite powder.

An Efficient RuTe2 /Graphene Catalyst for Electrochemical Hydrogen Evolution Reaction in Acid Electrolyte.

Developing efficient powder catalysts for hydrogen evolution reaction (HER) in the acidic electrolyte is significant for hydrogen generation in the proton exchange membrane (PEM) water electrolysis technique. Herein, we demonstrated an efficient catalyst for HER in the acid media based on the graphene supported ruthenium telluride nanoparticles (RuTe2 /Gr). The catalysts were easily fabricated by a facile microwave irradiation/thermal annealing approach, and orthorhombic RuTe2 crystals were found anchored over the graphene surface. The defective structure was demonstrated in the aberration-corrected transmission electron microscopy images for RuTe2 crystals and graphene support. This catalyst required an overpotential of 72 mV to drive 10 mA cm-2 for HER when loading on the inert glass carbon electrode; Excellent catalytic stability in acidic media was also observed to offer 10 mA cm-2 for 10 hours. The Volmer-Tafel mechanism was indicated on RuTe2 /Gr catalyst by Tafel slope of 33 mV dec-1 , similar to that of Pt/C catalysts. The high catalytic performance of RuTe2 /Gr could be attributed to its high dispersion on the graphene surface, high electrical conductivity and low charge transfer resistance. This powder catalyst has potential application in the PEM water electrolysis technique because of its low cost and high stability.

Cu Nanoparticle-Loaded Nanovesicles with Antibiofilm Properties. Part I: Synthesis of New Hybrid Nanostructures.

Copper nanoparticles (CuNPs) stabilized by quaternary ammonium salts are well known as antimicrobial agents. The aim of this work was to study the feasibility of the inclusion of CuNPs in nanovesicular systems. Liposomes are nanovesicles (NVs) made with phospholipids and are traditionally used as delivery vehicles because phospholipids favor cellular uptake. Their capacity for hydrophilic/hydrophobic balance and carrier capacity could be advantageous to prepare novel hybrid nanostructures based on metal NPs (Me-NPs). In this work, NVs were loaded with CuNPs, which have been reported to have a biofilm inhibition effect. These hybrid materials could improve the effect of conventional antibacterial agents. CuNPs were electro-synthesized by the sacrificial anode electrolysis technique in organic media and characterized in terms of morphology through transmission electron microscopy (TEM). The NVs were prepared by the thin film hydration method in aqueous media, using phosphatidylcholine (PC) and cholesterol as a membrane stabilizer. The nanohybrid systems were purified to remove non-encapsulated NPs. The size distribution, morphology and stability of the NV systems were studied. Different quaternary ammonium salts in vesicular systems made of PC were tested as stabilizing surfactants for the synthesis and inclusion of CuNPs. The entrapment of charged metal NPs was demonstrated. NPs attached preferably to the membrane, probably due to the attraction of their hydrophobic shell to the phospholipid bilayers. The high affinity between benzyl-dimethyl-hexadecyl-ammonium chloride (BDHAC) and PC allowed us to obtain stable hybrid NVs c.a. 700 nm in diameter. The stability of liposomes increased with NP loading, suggesting a charge-stabilization effect in a novel antibiofilm nanohybrid material.

Biodiesel production from the Chlorella vulgaris and Spirulina platensis microalgae by electrolysis using CaO/KOH-Fe3O4 and KF/KOH-Fe3O4 as magnetic nanocatalysts

Based on the results from recent studies on biodiesel production, in addition to cost reduction, the electrolysis method has both quantitative and qualitative advantages over the reflux method. Thus, in this study, biodiesel was produced by the electrolysis of the oil of two sea microalgae strains, namely Chlorella vulgaris and Spirulina platensis, using methanol and prepared CaO/KOH-Fe3O4 and KF/KOH-Fe3O4 magnetic nanocatalysts. At the first step, magnetic nanocatalysts were prepared, Scanning electron microscope and X-ray diffraction patterns of the prepared nanocatalysts were studied, and the calculated average crystal size of CaO/KOH-Fe3O4 and KF/KOH-Fe3O4 was 55.91 nm and 42 nm, respectively. Brunauer-Emmett-Teller analysis was performed for the determination of the active surface area. Then, two types of mentioned nonfood microalgae were cultured, and the oil of them was extracted. The most suitable microalgae between these two types with regard to the culture condition was chosen for the last step. Then, electrolysis technique contains two graphite plate electrodes (3 cm × 3 cm) that are separated by a distance of 2 cm and potential difference of 54 V with the electrolysis cell which was filled with 100 mL of reaction mixture containing methanol, the aforementioned microalgae oil, Tetrahydrofuran (THF), water, and nanocatalysts was performed for biodiesel production. The effect of catalyst weight percentage (1, 1.5, 2 wt%), molar ratio of alcohol to oil (5:1, 6:1, 7:1), and the reaction time (30, 60, 120, 180 min) in the efficiency of biodiesel production was investigated, and the physical properties of the prepared biodiesel were quantified. Based on the results, Chlorella vulgaris microalgae because of the more obtainable oil shows the priority of microalgae over Spirulina platensis and KF/KOH-Fe3O4 is an optimal choice catalyst for biodiesel production. The optimal condition was using 1.5 wt% of catalyst, methanol/oil molar ratio of 1:6, temperature of 25 °C, stirring speed of 400 rpm, and the reaction time of 2 h. Furthermore, B20 was prepared using the obtained biodiesel, and the quality was in accordance with the world standard of fuel ASTM D975, with the process yield of 96.8%, and no saponification side reaction, and KF/KOH-Fe3O4 showed the higher mass yield in transesterification reaction.

(Calamansi) Citrofortunella Microcarpa Rind Extract As Plant Derived Green Corrosion Inhibitor For Mild Steel In 1.0M Hcl

The inhibitive action of extracts from Citrofortunella microcarpa (Calamansi) peels on mild steel in 1.0M HCl solution has been studied using the weight-loss method, electrochemical method, and SEM-EDX analysis. The measurements showed that calamansi peels have good inhibition properties. Weight loss results suggest that inhibitive efficiency increases as the concentration increases. It was also found that the adsorption stabilizes at 72 hours and degrades at longer immersion times. SEM studies of the immersed mild steel showed the decreasing extent of corrosion attack on mild steel at an increasing ratio of inhibitor, while EDX analysis shows the reduction of the formation of corrosion products, suggesting the formation of inhibitor film on the mild steel surface. The Calamansi peel extract inhibitor obeys the Langmuir adsorption isotherm model and the mode of adsorption was found to be physical and spontaneous. The results of the electrolysis technique have shown the favoring of inhibition in cathodic reactions.

Eco-friendly synthesis of biodiesel from WCO by using electrolysis technique with graphite electrodes

Biodiesel is an environmentally viable fuel due to the depleting fossil fuel resources. In this research, the electrolysis method (EM) with graphite electrode has been used for synthesis biodiesel from waste cooking oil (WCO) as a sustainable feedstock. To carry out the process of transesterification of WCO, the ambient temperature was selected. The effects of methanol/WCOs ratio and sodium hydroxide or potassium hydroxide concentration as a catalyst on the biodiesel conversion were carefully investigated. Under the appropriate transesterification conditions; sodium hydroxide or potassium hydroxide (1 wt% cat /oil ratios) with optimum solvent-to-oil molar ratios(1:7/5), and water (2 wt%) is applied. The results revealed that the best sample synthesized of biodiesel was achieved without using co-solvent. Fourier Transform Infrared (FT-IR), GC-Mass and Viscosity characterization were used the assessing techniques for detection of WCO and biodiesel. The results showed that due to the characteristics of the graphite electrode, there is no voltage drop or reduce in reaction speed. The temperature from the beginning to the end of the reaction is constant, which ultimately leads to the production of biodiesel with 98% efficiency.

Novel treatment with percutaneus electrolysis in cervical whiplash syndrome

Introduction and Aims Cervical whiplash syndrome (CWS) commonly occurs because of the rear impact of motor vehicle collisions, producing a forced passive extension of the neck, followed by a rapid flexion in the form of a whip. This violent flexion can lead to an enthesopathy of the levator scapulae muscle (LS). The aim of this study was to evaluate the effectiveness of the percutaneous needle electrolysis (PNE) technique on the enthesopathy of the LS after a CWS and to compare this with a conventional physical therapy protocol. Material and Methods In a physical therapy center specialized in traffic accidents, we arranged to interview a sample of 100 voluntary patients, providing subjects with the inclusion-exclusion criteria and an informed consent form. Participants recruited to the study had their pain quantified using the visual analog scale (VAS) for pain, the validated neck pain questionnaire (NPQ), and an algometer. Two groups were created. One received the PNE technique and the other received the conventional physiotherapy protocol. Once treatments were completed, pain was quantified once again and the results were obtained. Results The most important findings are highlighted, regarding the comparison of variables of pain quantification in both groups and regarding the cost per treatment session. Conclusions 1. The conventional physiotherapy protocol used is effective for the reduction of pain in the SLC in the enthesopathy of the LS.2. Treatment with the PNE technique is effective for the reduction of pain in the CWS for LS enthesopathy.3. Physiotherapy treatment which includes the PNE technique is more effective in the algometry variable than treatment performed with conventional physiotherapy techniques by 16.8%.3. The PNE technique is superior to the protocol of conventional physiotherapy in the cost/effectiveness relationship by 85%.4. The PNE technique, without combining the same with any other physiotherapy technique, is effective for the reduction of pain in cases of enthesopathy.

Percutaneous needle electrolysis and exercise reduce the time for return to competition after an injury to the hamstrings: Two cases in professional football players

Abstract Background and Aims Percutaneous needle electrolysis has shown to be effective for the treatment of chronic tendinopathies, however, the scientific evidence available regarding acute muscle lesions is scarce. Lesions to the hamstrings caused by indirect mechanisms represent the most common muscle lesion in football (its incidence increases each year) with a high rate of recurrence. The aim was to evaluate whether the application of percutaneous needle electrolysis and a program of functional exercise decreases the times for return to competition after an injury to the hamstrings in athletes, and to compare performance data of subjects during competition before and after the injury. Methods A case series. Two professional football players, belonging to a first league team in Spain with a grade 2 lesion in the semitendinosus muscle on the proximal level. The affected muscle structure was assessed using ultrasound (Logiq GE E9, probe ML6–12) and functionality was evaluated based on data of the Global Positioning System (GPS), comparing the data obtained during the process of re-adaptation with data prior to the lesion. Percutaneous needle electrolysis was performed under ultrasound guidance at 48 hours after the injury following the protocol defined by Valera & Minaya (2:3:5). The indoor recovery of players began 24 hours after the percutaneous needle electrolysis. Initially, the exercise program included activities of mobility and controlled loading. Thereafter, the players completed their readaptation program in the training field with exercises of progressive complexity and intensity (biomechanical patterns and neuromuscular control of the central zone and the lower limbs, sprint). Results Player A returned to competition in 16 days, player B returned in 14 days. No adverse effects were identified during or after the percutaneous needle electrolysis technique. The players only missed one competition game and the process of readaptation allowed them to return to play registering parameters which were similar to the values prior to the lesion, and maintaining the performance during the four matches following the intervention protocol. The players were followed up to eight months after the injury and neither player suffered a relapse during this period, which indicates the complete recovery of the injured muscle both on a structural and functional level. Conclusions The combined treatment using percutaneous needle electrolysis and a functional exercise program reduces the time for return to competition after a grade 2 muscle lesion in the hamstrings, with a level of performance that is similar to prior to the lesion, without relapses, in an 8 month follow up period. The criteria we use to determine when a player can return to train with the team and compete after an acute muscle injury are: the time that has passed since the lesion, structural changes and the ability to perform tasks.

Characteristics of a New Polymer Electrolyte Electrolysis Technique with Only Cathodic Media Supply Coupled to a Photovoltaic Panel

Herein we discuss polymer electrolyte membrane (PEM) electrolysis stacks and systems we developed that are optimized for direct coupling to a photovoltaic (PV) panel. One advantage of PEM systems is their use of non-corrosive and non-toxic media. Thus, safe outdoor operation can be guaranteed, even in the case of a leakage. The system design was adapted to reduce the number of connection tubes, allowing for a series connection of multiple stacks at low cost and high reliability. One coupled PEM/PV system was tested under various temperature and irradiance conditions. All system components were also thoroughly characterized. The characterization was used to calibrate simple models of the individual components. Finally, the models were used to predict the system’s solar-to-hydrogen efficiency under different operating conditions and to find an optimal configuration for real-world outdoor operation.

CVD grown defect rich-MWCNTs with anchored CoFe alloy nanoparticles for OER activity

In this work we report synthesis of defect-rich multiwalled carbon nanotubes (MWCNTs) by CVD on cobalt-iron-silica (CoFe-silica) nanocomposites prepared by alcogel electrolysis technique, which resulted into anchoring of CoFe alloy nanoparticles on defect rich-MWCNTs. Due to defective nature of tubes and anchoring of particles, better OER activity is exhibited than bench mark iridium based (Ir/C) electrocatalyst and many other previously reported electrocatalysts in 1 M alkaline conditions.

La electrólisis percutánea y su eficacia en el tratamiento de tendinopatías en la extremidad inferior. Revisión sistemática

En los últimos años, la concepción que se tenía de las tendinopatías ha tolerado grandes cambios. La separación de las teorías que declaran a las tendinopatías como trastornos inflamatorios, a teorías que aluden una fisiopatología de carácter continúo basado en cambios degenerativos, propició la aparición de técnicas de fisioterapia invasiva como la electrólisis percutánea, que buscan romper con este proceso de degeneración, permitiendo la recuperación del tejido. El objetivo general de esta revisión sistemática es, estudiar la eficacia y evidencia científica de la técnica del electrólisis percutánea aplicada al tratamiento de tendinopatías en la extremidad inferior, para comparar los resultados obtenidos. Para lo cual, se realizó una búsqueda sistemática de estudios en 6 bases de datos, empleando las palabras clave: patellar tendinopathy unido con electrolysis, treatment, physical therapy y rehabilitation, lo cual ofreció 28 artículos, de los cuales, 8 se emplearon en la revisión, concretamente, 5 estudios de series de casos y 2 estudios prospectivos en ratas y 1 caso clínico. La electrólisis percutánea, mostró una mejora funcional y en la sensación dolorosa, al ser combinada con terapias de ejercicios excéntricos. El tratamiento terapéutico de las tendinopatías en la extremidad inferior mediante electrólisis percutánea, brinda resultados muy promisorios, sin embargo, para establecer la consecuencia de estos resultados, requiere del aporte de una cantidad sustancialmente mayor de estudios con una metodología más sofisticada, que sustenten su evidencia científica.

Conversion of Sodium Lactate to Lactic acid and Sodium Hydroxide with Cation Exchange Membrane Electrolytic Cell

This research conversion of sodium lactate to lactic acid and sodium hydroxide with electrolysis technique combined with cation exchange membrane (CEM). The electrolytic cell has effective membrane area of 144 cm2. Experiments were carried out by feeding sodium lactate solution which was prepared with alkaline degradation of invert sugar. This solution was feed through the anolyte. The process was studied in terms of the initial concentration of sodium lactate (i.e. 0.75, 1.20 and 1.50 M) and the applied voltage (i.e. 4, 6 and 8 volt) to assess the efficiency of separation. The results suggested that the transport of sodium ion through the membrane was proportional to the applied voltage but it was not depend on sodium lactate concentration which was used as feed. The current efficiency increased as the applied voltage increased. Conversely, the energy consumption with respect to sodium hydroxide production increased with both factors. From this experiment, it was found that the highest lactic acid recovery was 55.5% at 4 volt and initial lactate concentration of 0.75 M.

REMOVING ARSENIC AND FLUORIDE FROM HOT SPRING WATER BY ELECTROLYSIS

Currently in Japan, there are many hot springs containing fluoride and arsenic with high concentration. Although the national minimum effluent standard for arsenic and fluoride is 100 µg/L and 8 mg/L, respectively, they are not applied to the hotels with hot spring since no appropriate treatment techniques are available. The objective of this research is to reduce fluoride and arsenic in hot spring wastewater by using electrolysis technique to meet the national minimum effluent standards. The electrolysis system with an anode bath and a cathode bath separated by a diaphragm was adopted. Fluoride and arsenic co-precipitate with magnesium hydroxide formed in the cathode bath in which pH value increases as the electrolysis progresses. The Gero hot spring containing fluoride and arsenic as 17 mg/L and 120 µg/L, respectively, was used as a model effluent. Since Gero hot spring water contains almost no magnesium, magnesium chloride was added as a magnesium source. The addition of 100-200 mg/L could reduce the fluoride concentration to less than 8 mg/L. The arsenic concentration decreased to less than 10 μg/L. 1040 C/L of electricity was required for the operation. The electrolysis system successfully reduces the fluoride and arsenic concentrations below the national minimum effluent standards.

MWCNTs and carbon onions grown by CVD method on nickel-cobalt alloy nanocomposites prepared via novel alcogel electrolysis technique and its oxygen evolution reaction application

Novel nanocatalyst designs to synthesize carbon based electrocatalyst are highly desirable for the production of sustainable energy technologies like hydrogen through electrochemical water splitting. Herein, we report alcogel electrolysis technique to prepare nickel cobalt alloy nanoparticles in silica matrix and then growth of carbon nanostructured material by chemical vapour deposition (CVD) method for its application towards electrochemical catalysis of oxygen evolution reaction. The growth conditions of carbon nanostructures specially multiwalled carbon nanotubes (MWCNTs) and carbon onions are tuned by controlling the temperature of CVD. It is found that MWCNTs at temperature of 650 °C are preferentially formed while carbon onions are formed predominantly at 750 °C. The onion like carbon formed on Ni-Co alloy nanostructures at temperature of 750 °C is attributed to over growth of NiCo alloy nanoparticles achievable at higher temperatures. The diameter of MWCNTs were found to be in the range of 5–25 nm while carbon onions in the range 50–100 nm as revealed by TEM studies after etching silica particles by HF. The oxygen evolution reaction activity of the sample synthesized at 750 °C was found to be inferior than exhibited by MWCNTs formed at 650 °C which was possibly due to the presence of bigger size carbon onions having a less surface area. The overpotential exhibited by NiCo-MWCNTs is 340 mV which is just 35 mV higher than bench mark Ir/C catalyst. The better OER performance exhibited by NiCo-MWCNTs is devoted to encapsulated nickel-cobalt alloy particles by well graphitized carbon layers, defective side walls of nanotubes and oxygenated functional groups (C=O, C–O) which are proven active sites for OER.

Highly Active Binder Free Plasma Sprayed Non-Noble Metal Electrodes for Anion Exchange Membrane Electrolysis at Different Reduced KOH Concentrations

The production of hydrogen by the water electrolysis technique to provide a fossil fuel alternative energy source has attracted a plethora of attention among the other different methods in the context of sustainability, renewable energy source utilization and green technology.[1] Conventional alkaline water electrolyzer (AWE) offers many advantages compared with other systems. One of the major advantages of AWE over proton exchange membrane water electrolyser (PEMWE) is the replacement of conventional noble metal electrocatalysts with active, stable and relatively low-cost transition metal catalysts. However, AWE electrolyzers suffer from lower operational current density compared with their PEMWE counterpart. Like AWE, anion exchange membrane (AEM) electrolyzer does not require noble metal catalysts, which makes this technology much less expensive than PEMWE, while possessing the advantage of PEMWE. However, the electrochemical water splitting performance of AEM water electrolysis is still much lower than that of PEMWE. Focusing on this issue, the presented work aims at improving the performance of AWE and AEM electrolysers by developing cost effective non-noble electrodes on macro-porous transport layer (MPL) using the air plasma spray deposition method.[2] MPLs were fabricated by depositing Ni-graphite on porous substrates. Graphite was removed during particle in-flight forming a controlled porous layer. Electrodes were developed by plasma spraying of NiMoAl for cathode and NiAl for anode on top of the MPL followed by activation in which Al was partially leached out from layers of both electrodes using an alkaline solution. Electrochemical tests were conducted on half-cell in 6M KOH solution and then in the full cells for AWE and AEM in 6M and 0.3M KOH, respectively. The electrochemical performance is recorded via over-potential measurements, electrochemical impedance spectroscopy (EIS), cyclic voltammetery and polarization curve. With optimal combination of MPL and electrodes, current density of 0.5 Acm-2 at 1.80 V was recorded as the initial performance in 6M solutions for AWE using Zirfon separator and the current density of 0.31 Acm-2 at 1.80 V was recorded for AEM electrolyzer with more dilute KOH solution (0.3M) using an anion exchange membrane. 64 days of abusive testing was conducted for the AWE without measurable degradation in the performance in 6M KOH. The catalysts developed in this work will be promising in supporting the pursuit of cheap, affordable and ideal eco-friendly hydrogen fuel. [1] F. Razmjooei, K.P. Singh, D.S. Yang, et al., Acs Catalysis, 2017, 7, 2381-2391. [2] A.S. Gago, S.A. Ansar, B. Saruhan, et al., J Power Sources, 2016, 307, 815-825.