Fabrication of Nanostructured Ni and Ni-Pd electrodes for wateralkaline electrolyzer

In the last years many attention has been dedicated to the increase of performance of Nichel based electrodes to use in water-alkaline electrolyzes. In our preliminary work we have shown that alkaline electrolyzer made with Ni nanowires covered with IrO2 (side oxygen evolution) nanoparticles and a Ni sheet (side hydrogen evolution) have very good and stable performance also at room temperature [1]. In this work, to obtain a complete nanostructured electrolyzer, the attention was focused on the fabrication of electrodes for hydrogen evolution. In particular, by metal displacement deposition we have grown on Ni nanowires electrodes, nanoparticles of Pd with the aim to enhance the electrocatal…

Calcium phosphate/polyvinyl acetate coatings on SS304 via galvanic co-deposition for orthopedic implant applications

Abstract In this work, the galvanic deposition method is used to deposit coatings of brushite/hydroxyapatite/polyvinyl acetate on 304 stainless steel. Coatings are obtained at different temperatures and with different sacrificial anodes, consisting of a mixture of brushite and hydroxyapatite. Samples are aged in a simulated body fluid (SBF), where a complete conversion of brushite into hydroxyapatite with a simultaneous change in morphology and wettability occurred. The corrosion tests show that, compared with bare 304, the coating shifts Ecorr to anodic values and reduces icorr Ecorr, and icorr has different values at different aging times due to chemical interactions at the solid/liquid i…

Ni alloy nanowires for alkaline electrolysers

In recent years, the interest towards green hydrogen has drastically increased due to the global decarbonization process. Green hydrogen is obtained by water electrolysis using only electricity from renewable sources. It is considered one of the best storage systems in terms of environmental sustainability but not in economic ones. Nowadays, the research is focused on improving the Alkaline Water Electrolysis (AE) to reduce the cost of production. An approach to improve AE performance is based on nanostructured electrodes characterized by high electrocatalytic activity due to the very high surface area. In fact, the development of more efficient electrolysers with low-cost electrode-electro…

PEM electrolyzer characterization with carbon-based hardware and material sets

Abstract The research and development of proton exchange membrane water electrolysis (PEMWE) is an upcoming and growing area due to a rising interest in hydrogen as an energy carrier. Operating conditions are harsher than in a fuel cell system, particularly because the potentials required for the oxygen evolution reaction are significantly higher. In commercial water electrolysis systems, this is compensated by typically using titanium material sets that are often protected against oxidation through coating processes. Such material choices make small scale research hardware and porous transport layers expensive and difficult to source. In this work, we show that the stability of traditional…

Electrodeposited nickel–zinc alloy nanostructured electrodes for alkaline electrolyzer

Abstract Over the last decade, as a consequence of the global decarbonization process, the interest towards green hydrogen production has drastically increased. In particular a substantial research effort has focused on the efficient and affordable production of carbon-free hydrogen production processes. In this context, the development of more efficient electrolyzers with low-cost electrode/electrocatalyst materials can play a key role. This work, investigates the fabrication of electrodes of nickel-zinc alloys with nanowires morphology cathode for alkaline electrolyzers. Electrodes are obtained by the simple method of template electrosynthesis that is also inexpensive and easily scalable.…

Nanostructured Ni–Co alloy electrodes for both hydrogen and oxygen evolution reaction in alkaline electrolyzer

Abstract Ni–Co alloy nanostructured electrodes with high surface area were investigated both as a cathode and anode for an alkaline electrolyzer. Electrodes were obtained by template electrosynthesis at room temperature. The electrolyte composition was tuned in order to obtain different NiCo alloys. The chemical and morphological features of nanostructured electrodes were evaluated by EDS, XRD and SEM analyses. Results show that electrodes with different composition of Ni and Co, made of nanowires well anchored to the substrate, were obtained. For both hydrogen and oxygen evolution reactions, electrochemical and electrocatalytic tests, performed in 30% w/w KOH aqueous solution, were carried…

Controlled solution-based fabrication of perovskite thin films directly on conductive substrate

Abstract Organometallic perovskites are one of the most investigated materials for high-efficiency thin-film devices to convert solar energy and supply energy. In particular, methylammonium lead iodide has been used to realize thin-film perovskite solar cells, achieving an efficiency higher than 20%. Different fabrication procedures based on the spin-coating technique have been proposed, which do not ensure homogenous morphologies. In this work, we present a scalable process to fabricate methylammonium lead iodide thin films directly on conductive substrates, consisting of electrodeposition and two subsequent chemical conversions. A thorough investigation of the morphological, structural an…

Pd-Co-Based Electrodes for Hydrogen Production by Water Splitting in Acidic Media

To realize the benefits of a hydrogen economy, hydrogen must be produced cleanly, efficiently and affordably from renewable resources and, preferentially, close to the end-users. The goal is a sustainable cycle of hydrogen production and use: in the first stage of the cycle, hydrogen is produced from renewable resources and then used to feed a fuel cell. This cycle produces no pollution and no greenhouse gases. In this context, the development of electrolyzers producing high-purity hydrogen with a high efficiency and low cost is of great importance. Electrode materials play a fundamental role in influencing electrolyzer performances; consequently, in recent years considerable efforts have b…

Nanostructured nickel–zinc alloy electrodes for hydrogen evolution reaction in alkaline electrolyzer

Evolutionary Design Optimization of an Alkaline Water Electrolysis Cell for Hydrogen Production

Hydrogen is an excellent energy source for long-term storage and free of greenhouse gases. However, its high production cost remains an obstacle to its advancement. The two main parameters contributing to the high cost include the cost of electricity and the cost of initial financial investment. It is possible to reduce the latter by the optimization of system design and operation conditions, allowing the reduction of the cell voltage. Because the CAPEX (initial cost divided by total hydrogen production of the electrolyzer) decreases according to current density but the OPEX (operating cost depending on the cell voltage) increases depending on the current density, there exists an optimal cu…

Ni alloy nanowires as high efficiency electrode materials for alkaline electrolysers

Abstract The fabrication and characterization of nickel-alloy electrodes for alkaline electrolysers is reported. Three different alloys (Ni–Co, Ni–Zn and Ni–W) at different composition were studied in order to determine the optimum condition. Nanostructured electrodes were obtained by template electrodeposition into a nanoporous membrane, starting from aqueous solution containing the two elements of the alloy at different concentrations. Composition of alloys can be tuned by electrolyte composition and also depends on the difference of the redox potential of elements and on the presence of complexing agents in deposition bath. Electrochemical and electrocatalytic tests, aimed at establishin…

Nanostructured Ni Based Anode and Cathode for Alkaline Water Electrolyzers

Owing to the progressive abandoning of the fossil fuels and the increase of atmospheric CO2 concentration, the use of renewable energies is strongly encouraged. The hydrogen economy provides a very interesting scenario. In fact, hydrogen is a valuable energy carrier and can act as a storage medium as well to balance the discontinuity of the renewable sources. In order to exploit the potential of hydrogen it must be made available in adequate quantities and at an affordable price. Both goals can be potentially achieved through the electrochemical water splitting, which is an environmentally friendly process as well as the electrons and water are the only reagents. However, these devices stil…

Nanostructured electrodes for hydrogen production in alkaline electrolyzer

Abstract Ever-widespread employment of renewable energy sources, such as wind and sun, request the simultaneous use of effective energy storage systems owing to the intermittent and unpredictable energy generation by these sources. The most reliable storage systems currently under investigation are batteries and electrochemical cells for hydrogen production from water splitting. Both systems store chemical energy which can be converted on demand. The low power density is the weakness of the batteries while the high production cost limits currently the wide use of hydrogen from electrochemical water splitting. In this work, attention was focused on the use of nanostructured Ni as a cathode f…

FLEXIBLE ELECTRODE BASED ON GOLD NANOPARTICLES AND REDUCED GRAPHENE OXIDE FOR URIC ACID DETECTION USING LINEAR SWEEP VOLTAMMETRY

In this work, an electrochemical sensor for uric acid determination is shown with a preliminary study for its validation in real samples (milk and urine). Uric acid can be electrochemically oxidized in aqueous solutions and thus it is possible to obtain electrochemical sensors for this chemical by means of this electrooxidation reaction. Indium tin oxide coated on flexible polyethylene terephthalate substrate, modified with reduced graphene oxide and gold nanoparticles by co-electrodeposition, was used. Electrodeposition was performed at -0.8V vs SCE for 200 s. All samples were characterized by electron scan microscopy and electron diffraction spectroscopy. A careful investigation on the ef…

Nanostructured Electrochemical Devices for Sensing, Energy Conversion and Storage

Nanomaterials are very promising to enhance device performances for sensing, sustainable energy production, and energy conversion and storage, as extensively reported in the literature [1-3]. In this field, one of the most severe challenge is to find suitable methods for fabricating nanomaterials. Over the years, numerous preparation methods were proposed in the literature, but not all of them are easily scalable and economically advantageous for industrial application. In this context, electrochemical deposition in template is a facile method for fabricating either two- or one-dimensional nanostructured materials because it allows to easily adjust the fundamental parameters controlling the…

NANOSTRUCTURED ELECTRODES FOR HYDROGEN PRODUCTION IN ALKALINE ELECTROLYZER

Nanostructured lead acid battery for electric vehicles applications

This paper presents an innovative lead acid battery, based on nanostructured active materials. Both charging time and specific energy are greatly enhanced in comparison with commercial lead acid battery. Starting from the extremely valuable performances of the nanostructured battery, also a circuital model, for application in electric vehicle traction, has been specifically developed. The circuital model has demonstrated that an enhanced nanostructured battery allows an increase of traveled distance by electric vehicles.

Ni-Fe alloy nanostructured electrodes for water splitting in alkaline electrolyser

Abstract In this work, nickel-iron alloy nanostructured electrodes obtained by template electrosynthesis method are investigated for both hydrogen and oxygen evolution reactions. Electrodes consist of nanowire arrays with high surface area that are able to ensures a high electrolytic activity. To obtain different alloy compositions, the concentration of the elements in the deposition baths is appropriately tuned. Results show that the composition of nanowires does not change linearly with the composition of deposition bath but are richer in Fe. Nanostructured electrodes are tested as both cathodes and anodes in 30 wt% KOH aqueous solution, at room temperature to determine the best alloy com…

Nanostructured Lead Electrodes with Reduced Graphene Oxide for High-Performance Lead–Acid Batteries

Nanostructured Pb electrodes consisting of nanowire arrays were obtained by electrodeposition, to be used as negative electrodes for lead–acid batteries. Reduced graphene oxide was added to improve their performances. This was achieved via the electrochemical reduction of graphene oxide directly on the surface of nanowire arrays. The electrodes with and without reduced graphene oxide were tested in a 5 M sulfuric acid solution using a commercial pasted positive plate and an absorbed glass mat separator in a zero-gap configuration. The electrodes were tested in deep cycling conditions with a very low cut-off potential. Charge–discharge tests were performed at 5C. The electrode wi…

Eulerian two-fluid model of alkaline water electrolysis for hydrogen production

Hydrogen storage is a promising technology for storage of renewable energy resources. Despite its high energy density potential, the development of hydrogen storage has been impeded, mainly due to its significant cost. Although its cost is governed mainly by electrical energy expense, especially for hydrogen produced with alkaline water electrolysis, it is also driven by the value of the cell tension. The most common means of electrolyzer improvement is the use of an electrocatalyst, which reduces the energy required for electrochemical reaction to take place. Another efficient means of electrolyzer improvement is to use the Computational Fluid Dynamics (CFD)-assisted design that allows the…

Nanostructured Nickel alloy electrodes for alkaline electrolysers

Initial approaches in benchmarking and round robin testing for proton exchange membrane water electrolyzers

Abstract As ever-increasing amounts of renewable electricity enter the energy supply mix on a regional, national and international basis, greater emphasis is being placed on energy conversion and storage technologies to deal with the oscillations, excess and lack of electricity. Hydrogen generation via proton exchange membrane water electrolysis (PEMWE) is one technology that offers a pathway to store large amounts of electricity in the form of hydrogen. The challenges to widespread adoption of PEM water electrolyzers lie in their high capital and operating costs which both need to be reduced through R&D. An evaluation of reported PEMWE performance data in the literature reveals that there …

Performance Enhancement of Alkaline Water Electrolyzer Using Nanostructured Electrodes Synthetized by Template Electrosynthesis

The increase of power generation by renewable sources is causing problems in the management of the electricity grid. In order to favor the transition from the current energy production towards renewable energy sources, it is necessary to plan strategy to develop suitable energy storage systems. Certainly, the electrochemical hydrogen production can be considered as one of the most promising storage technologies. In this work, an innovative alkaline electrolyzer is presented from its design based on the use of nanostructured electrodes up to its implementation suggested by the results of tests simulating real operation. The nanostructured electrodes were fabricated by template electrosynthes…

Nanostructured Ni-Co Alloy Electrodes Fabrication and Characterization for both Hydrogen and Oxygen Evolution Reaction in Alkaline Electrolyzer

Sun and wind as power sources are becoming more and more relevant owing to the progressive abandoning of the fossil fuels [1,2]. Additionally, worldwide public authorities are encouraging the use of renewable energies by promoting laws and guidelines [3,4]. In this scenario, a fundamental role can play hydrogen that besides being a valuable energy carrier, it can also act as a storage medium to balance the discontinuity affecting the renewable energy sources production [5]. As a consequence, cheap and abundant availability of hydrogen is crucial. Electrochemical water splitting is likely one of the most valuable technique to produce hydrogen because the process is environmentally friendly b…

Optimization of Electrodeposited Nickel-Zinc Alloys for Alkaline Electrolyzer with Nanostructured Electrodes

It is common opinion that hydrogen will become increasingly important over time. However, many research efforts still need to be made to develop efficient, low-cost and carbon-free hydrogen production. In this context, electrolysers will play a key role, but it is necessary to develop efficient and low-cost electrode/electrocatalyst materials. In this work, Nickel-Zinc alloy electrodes with nanowires morphology were investigated as cathode for alkaline electrolyzer. Electrodes were obtained by the simple method of template electrosynthesis that is also inexpensive and scalable. Nanostructured electrodes were analysed by morphological and chemical analyses. The nanowires composition is depen…

Ni-Based Alloy Nanostructured Electrodes for Alkaline Electrolyzers

In water alkaline electrolyzer field, the development of Nickel-based nanostructured electrode is one of the possible ways to improve the water electrolysis efficiency

Fabrication of Nanostructured Ni and Ni-IrO2 electrodes for wateralkaline electrolyzer

In the field of water-alkaline electrolyzer, the develop of nanoporous nickel electrodes with low cost and high electrocatalysis efficiency is one of the potential approaches to increase their performance [1]. To obtain nanostructured electrodes, a facile approach is that of template electrosynthesis. With this method we have obtained electrodes made of nanowires of Ni that have a very high surface area. These electrode were obtained by a two-step procedure allowing to obtain an ordered array of Ni nanowires that completely covering the surface of current collector made of the same material. Besides, by amperostatic deposition we have covered these electrode with nanoparticles of IrO2 elect…

Dispositivo elettrolizzatore migliorato

Un dispositivo di elettrolizzatore migliorato per la produzione elettrolitica di idrogeno allo stato gassoso

Nanostructured Electrochemical Devices for Sensing, Energy Conversion and Storage

Nanostructured materials are attracting growing interest for improving performance of devices and systems of large technological interest. In this work, the principal results about the use of nanostructured materials in the field of electrochemical energy storage, electrochemical water splitting, and electrochemical sensing are presented. Nanostructures were fabricated with two different techniques. One of these was the electrodeposition of the desired material inside the channels of a porous support acting as template. The other one was based on displacement reaction induced by galvanic contact between metals with different electrochemical nobility. In the present work, a commercial polyca…