Concentrated Alkaline Media Research Articles

Controlling surface wetting in high-alkaline electrolytes for single facet Pt oxygen evolution electrocatalytic activity mapping by scanning electrochemical cell microscopy.

Scanning electrochemical cell microscopy (SECCM) has been used to explore structure-electrocatalytic activity relationships through high-resolution mapping of local activities of electrocatalysts. However, utilizing SECCM in strongly alkaline conditions presents a significant challenge due to the high wettability of the alkaline electrolyte leading to a substantial instability of the droplet in contact with the sample surface, and hence to unpredictable wetting and spreading of the electrolyte. The spreading phenomena in SECCM is confirmed by the electrochemical response of a free-diffusing redox probe and finite element method (FEM) simulations. Considering the significance of alkaline electrolytes in electrocatalysis, these wetting issues restrict the application of SECCM for electrocatalyst elucidation in highly alkaline electrolytes. We resolve this issue by incorporating a small percentage of polyvinylpyrrolidone (PVP) in the electrolyte inside the SECCM capillary to increase the surface tension of the electrolyte. To demonstrate successful wetting mitigation and stable SECCM mapping, we performed oxygen evolution reaction (OER) mapping on polycrystalline Pt by using 1 M KOH with an optimized PVP concentration. The OER activity maps correlated with the orientation of the exposed facets determined by electron backscatter diffraction and reveal different activities between Pt facets, hence confirming our methodology for exploring electrocatalytic activities in single facet scale in concentrated alkaline media. Interestingly, the maximum OER current density was highest for (110) and (111) which contradicts the activity trends in acidic electrolyte for which (100) is most active for the OER.

The passivity breakdown of zinc antimony alloy as an anode in the alkaline batteries

Zn is utilized as an anode in alkaline batteries because of its propensity to produce a passive colloidal layer on its surface. Then the surface should be reactivated in the passive region. Therefore, the passive state on the surface can be significantly hindered by utilizing a tiny percentage of Sb alloyed with Zn. Accordingly, the effect of minor Sb alloying with Zn on the performance of anodic dissolution and passivation in concentrated alkaline media (6 M KOH, which is used in the batteries) was studied using potentiodynamic and potentiostatic techniques. Besides, the passive layers formed at various anodic potentials were characterized utilizing scanning electron microscopy (SEM) and X-ray diffraction (XRD). The data of potentiodynamic measurements exhibited the active–passive transition curve of all studied specimens. All obtained results revealed that passivation is gradually hindered with increasing Sb content in the alloy, and less passivity was obtained at 1% Sb. Along this, a dramatic rise in current density at a particular positive potential (+ 2.0 V vs. SCE) to markedly higher values only of the electrodes containing Sb is observed.

Synthesis and characterization of metakaolin-based crystalline phase sodium aluminum silicon oxide geopolymers using concentrated alkaline medium

Crystalline phase geopolymers that include sodium aluminum silicon oxide were produced with high concentrations of NaOH activator in metakaolin–sodium silicate solution at 80 °C. Low-temperature geopolymerization provided these first-ever reported crystalline geopolymers when high NaOH concentration 12–15 M was used for the aqueous metakaolin medium. By changing the NaOH activator concentration to 10 M, amorphous geopolymers were formed, but crystalline geopolymers of sodium aluminum silicon oxide appeared in the NaOH concentration range. The crystalline phase had dense morphology of the formed bulk ceramics, respectively exhibiting 8.4 ± 0.5 MPa compressive strength at weight ratios of solid/liquid (S/L) and Na2SiO3/NaOH of mixtures for 0.45 and 1.0.

An insight into the electrochemical charge/discharge process of ceramic hydride electrodes for battery applications

The initial stage of the hydrogen absorption/desorption process in ceramic electrodes is discussed in this work. The experiments were carried out at 25 °C in a concentrated alkaline medium. The electrodes were prepared using LaB6 and LaBO3. Pd nanoparticles were incorporated into the electrodes to activate them electrochemically. The results showed that the electrodes could absorb hydrogen electrochemically at room temperature. The LaBO3 electrode showed better hydrogen absorption characteristics than LaB6. The morphological and volumetric properties were crucial in achieving the hydrogen storage in the electrode. The discharge capacity was similar in both electrodes. However, the LaBO3 electrode supplied more energy than the LaB6-based electrode. The charge absorption reaction prevailed in both electrodes instead of the hydrogen evolution reaction. The capability of the ceramic electrodes to absorb/desorb hydrogen electrochemically is controlled by the diffusion processes that occur at the electrode/electrolyte interface and the crystalline planes of the ceramic materials.

Scalable Preparation of Core-Shell Fep/N, P-Doped Porous Carbon Composite with a Superior Activity for Oxygen Evolution Reaction in Industry-Suitable Concentrated Alkaline Medium

Scalable Preparation of Core-Shell Fep/N, P-Doped Porous Carbon Composite with a Superior Activity for Oxygen Evolution Reaction in Industry-Suitable Concentrated Alkaline Medium

Enhanced sustainable electro-generation of a Ni (I) homogeneous electro-catalyst at a silver solid amalgam electrode for the continuous degradation of N2O, NO, DCM, and CB pollutants

This paper reports the sustainable and enhanced generation of a Ni(I) active electro-catalyst using AgSAE as a cathode material for the sustainable degradation of N2O, NO, dichloromethane (DCM), and chlorobenzene (CB) by electroscrubbing in a series operation. The AgSAE electrode showed 1.66 times higher Ni(I) formation than the Ag metal electrode. The AgSAE achieved 20% ± 2% Ni(I) generation in a highly concentrated alkaline medium, whereas Ag metal only achieved 12% ± 2% Ni(I) generation at the same current density. Electrochemical impedance spectroscopy and voltammetric studies determined that the kinetics of the charge-transfer reaction was also preferential at the AgSAE, with the cathodic peak at −1.26 V vs. Ag/AgCl confirming Ni(I) formation. Initially, the change in the oxygen reduction potential and reduction efficiency of Ni(I) confirmed the removal of N2O, NO, DCM and CB. In addition, the gas Fourier transform infrared (FTIR) spectrum revealed 99.8% removal efficiency of toxic pollutants. Therefore, the regeneration of Ni(I) confirmed the sustainable removal of toxic pollutants. Furthermore, the FTIR spectra revealed the formation of NH3 during the reduction of N2O and NO. On the other hand, DCM and CB were reduced to benzene derivatives in the solution phase. In addition, a plausible reduction mechanism was derived. As a result, the AgSAE cathode exhibited two-fold higher removal efficiency of N2O, NO, DCM, and CB than the previously reported electrodes.

Direct growth of Fe-incorporated NiSe microspheres on FeNi alloy foam as a highly efficient electrocatalyst for oxygen evolution reaction

Transition metal selenides with special structures and rational component modulation have received tremendous research interest to ameliorate the sluggish kinetics of oxygen evolution reaction (OER) in electrochemical water splitting. Here, we propose a facile hydrothermal treatment strategy to prepare porous Fe-incorporated NiSe microspheres via in situ selenization of iron–nickel foam. The as-obtained 3D integrated anode demonstrates excellent electrocatalytic performance towards OER in concentrated alkaline media (1.0 M KOH), with a small onset overpotential of 170 mV, an overpotential as low as 236 mV to achieve a current density of 50 mA cm−2, and a small Tafel slope of 53 mV dec−1. The overpotential at 50 mA cm−2 shows no obvious change during the whole durability test for 24 h, indicating long-term stable electrocatalytic activity. Characterizations of the electrode after stability test reveal the oxidation of the crystallized Fe-incorporated NiSe microspheres which probably generates amorphous Ni(Fe)OOH. The microspheres were partially dissolved and connected with each other to form a wormlike porous structure. The superior OER activity is largely attributed to the highly active Fe–Ni selenide and derived oxyhydroxide of 3D porous structure on the FeNi foam substrate. The facile synthesis strategy in this work can be conveniently applied to the preparation of a variety of selenides of metal foams with different compositions as highly efficient electrocatalysts.

Tuning hydrogen sorption properties of Pd by its alloying with Ru, Rh, and Pt: the study of binary alloys in concentrated alkaline media

The hydrogen electrosorption process was examined in 6 M KOH on Pd binary alloys, containing Rh, Ru, and Pt. Pd-alloys were electrochemically deposited on Au substrate. The electrodes were subjected to activation procedure—hydrogen pretreatment procedure (HPP) at first in 0.5 M H2SO4 and then in 6 M KOH. It was noticed that it was possible to achieve comparable reversibility of hydrogen electrosorption process in acid and in concentrated base. The obtained values of the α→β phase transition potential, hysteresis extent, and maximum hydrogen absorption capacity show good agreement with the data from acidic medium. The observed kinetics of hydrogen electrosorption were strongly hindered in concentrated alkaline media, whereas the influence of the electrolyte on the thermodynamic functions of hydrogen absorption is less pronounced.Graphical abstract

Study of passivation treatment on SS321 electrolyte reservoir used in AgO-Zn reserve battery, for defence applications

SS321 is used as the electrolyte reservoir to store potassium hydroxide electrolyte. The metal is prone to get corroded at the electrolyte environment. The present work is carried out for minimizing the corrosion of SS321 potassium hydroxide electrolyte reservoir which is a part of the AgO-Zn reserve primary battery by passivation with citric acid. The uniqueness of the present work exhibits the optimization of passivation method and process conditions, to withstand concentrated alkaline (KOH) medium stored in SS321 electrolyte reservoir, which is having a long life of more than 7 years. Polarization and KOH resistance tests suggest that AISI 321 showed excellent passivation studies behavior when treated with citric acid solution. Hence it is necessary to establish the corrosion behavior of SS321 electrolyte storage container in alkaline solution by electrochemical studies. The thickness loss and weight loss are the main parameters measured to quantify the amount of corrosion. The Voltammetry and AFM studies established the minimum corrosion rate by passivation process method. Based on the results of electrochemical studies and anodic polarization experiments, it was confirmed that the passivation layer formed by treating the material with Citric acid, is capable of improving the corrosion resistance of stainless steel significantly and the passive film is more stable than those produced by other passivating methods. Thus, to minimize the rate of corrosion on electrolyte storage container for the period of battery life of more than 7 years, citric acid passivation having a good corrosion resistance in concentrated alkaline electrolyte (KOH) medium, is best suited and the method of treatment involved is benign & environment friendly.

Novel process for decontamination and additional valorization of steel making dust processing using two-step correlative leaching

Recycling of steel making dusts often targets Zn removal. Other heavy metals such as Mo, W or Cr do not receive as much attention, and the decontamination of the dusts from these constituents is scarcely addressed in the literature. This study presents a novel approach of the selective separation of Mo from steel making dusts using alkaline solutions with low concentrations, before Zn removal using concentrated alkaline medium. Such an approach has never been reported before and can contribute to more efficient decontamination of the steel making dusts and will increase the value of recovered components since Mo can be significantly preconcentrated. Two samples originating from two steel producers were investigated. One sample contained 2.65% of Mo and 1.87% of Zn, and the second sample had 0.61% of Mo and 35.9% of Zn. Temperature was found to have a low impact on the leaching efficiency of Mo, while increased NaOH concentration promoted leaching of Zn. Excellent pre-concentration of Mo was achieved by using a S:L ratio of 1:3. Almost 5170 mg/L Mo, 1000 mg/L W, no Fe and only 2 mg/L Zn were present in the solution after leaching at 30 °C for 30 min. For the samples containing lower concentrations of Mo and high concentrations of Zn, the selectivity of the process was affected when using higher concentrations of NaOH. A final leachate containing 797 mg/L of Mo and only 11 mg/L Zn was obtained after leaching with 0.05 M NaOH. DFT computations showed that the 2D layered structures of MoO3 and WO3 are decisive factors that account for their high solubilites.

Electrochemical Method for Graphene Preparation from Multi-Walled Carbon Nanotubes

There are the numerous methods of graphene synthesis from multi-walled carbon nanotubes (MWCNTs): redox reaction, modification via incorporation of nitrogen and alkaline earth atoms; plasma sputtering; unzipping by microwave radiation, ultrasonic and electrical treatment, treatment with metallic catalytic particles, treatment with laser irradiation and scanning tunnelling microscope tip hydrogenation in high-temperature conditions, as well as unrolling by electrochemical methods [1]. Among these technologically advanced methods, the electrochemical process seems to be most promising since it can be easily controlled by selection of three parameters, namely current, voltage and time. As it is known from the literature, it is possible to carry out the electrochemical reduction of graphene oxide (GO) to electrochemical reduced graphene oxide (ERGO) in different media by a two-step electrochemical approach. Some investigators the processes of oxidation and reduction of graphene carried out in dilute sulfuric acid first at the anodic and then at cathodic polarization without changing the electrolyte. In our opinion, for more complete unzipping of nanotubes during their oxidation, more concentrated sulfuric acid should be used. The reduction process is preferably carried out in concentrated alkaline medium to neutralize the acid intercalated during oxidation. Additional cathode treatment in an alkaline medium will lead to an increase in the specific surface area and a more complete reducing to graphene. Therefore, the aim of our study was to develop a simple electrochemical method to produce ERGO as the catalyst carrier for oxygen electrodes for fuel cells using anodic oxidation of MWCNTs in an acidic medium and subsequent reduction in an alkaline medium. MWCNT diameter was 10-30 nm, and the specific surface area was 230 m2g-1. The number of walls ranged from 8 to 15. The anodic oxidation in sulphuric acid and the electrochemical reduction in alkaline electrolyte carried out in a galvanostatic. The materials synthesized via the electrochemical oxidation of MWCNTs with subsequent reduction were characterized using an electron microscopy (JEM-100 CXII), and X-ray diffraction (XRD) (DRON-4, CuKα radiation), Raman spectra and XPS spectra. Molecular species were analysed with FTIR spectroscopy. The obtained materials were investigated as cathode material for the oxygen electrodes of power sources in alkaline electrolyte. We have studied electrochemical characteristics of the oxygen electrodes produced by oxidation of the carbon nanotubes over different time. The MWCNT anodic oxidation was carried out under +3 V over 1.5, 4, and 5 hours. We found that in over conditions the more suitable time for the obtained electrochemical parameters (current density) of the oxygen electrodes is 4-hour oxidation duration. We have also studied the MWCNTs oxidation at various potentials for 4 hours. The potentials were chosen in the range +1.8–+4.5 V. Anodic oxidation during 4 hours at +3.0 V creates an extremely active catalytic material, which best suits for oxygen electrodes compared to those made of electrochemically oxidized MWCNTs at other potentials. The materials obtained by anodic oxidation of the carbon nanotubes were subsequently reduced in the alkaline solution at -1.4 V potential over 4 hours. The Raman spectra of all three measured samples show the presence of the Raman marker bands characteristic of the graphite structure, namely, D, G and 2D modes. Based on the analysis of the shape and position of these bands one can assume that after the anodic oxidation, the MWCNT crystallinity becomes worse while it improves after subsequent electrochemical reduction. This observation is also confirmed by corresponding XRD data. The frequencies for the D mode, G mode, and 2D mode suggest well-crystallized graphene structure. Closely positioned tags of C atoms in the XRD rings suggest that the synthesized sample consists of flat wavy sheets. As follows from the analysis of the Raman and IR spectra, XPS and XRD data, in the result of the MWCNT electrochemically treatment we obtained graphene nanoplatelets (Fig1), which contains carbon oxide groups on its surface. Electrodes based on electrochemically reduced graphene nanoplatelets produced from oxidized MWCNTs have the electrocatalytic characteristics close to those of the electrodes from MWCNTs containing deposited platinum. Obtained graphene nanoplatelets were stable over six months subject to testing in the fuel cell mock-up galvanostatic mode. The electrochemical synthesis of graphene nanoplatelets via anodic oxidation of MWCNTs and it reduction has been confirmed by electron microscopy, XRD, X-ray fluorescence, IR and Raman spectroscopy. Electrochemical studies have shown that the obtained graphene are promising materials as a catalyst carrier for fuel cells oxygen electrodes. M.O. Danilov, et al., Graphene Science Handbook. Fabrication Methods, (Eds. M. Aliofkhazraei, et al.), CRC Press/Taylor & Francis, 2016, pp. 205. Figure 1

The effect of alkaline solution seepage on deformation appearances in the soil foundation of engineering structures

Aim. This study aims to analyze the influence of static loading and descending seepage of concentrated alkaline solution on deformation appearances in the soil foundation and forming the construction tilt using the example of an overhead crane. Methodology. The methodology of research included laboratory determination of the physico-mechanical and subsidence properties of soils focusing on alluvial-diluvial loam and groundwater chemical composition at the studied site, evaluation of leaching parameters of loam soil phase by an alkaline solution using the X-ray fluorescent spectrometer СЕР-01 ElvaX Plus, and variable-based calculations of soil subsidence based on the standard techniques applied in geotechnics taking into account partial dissolution of soil solid phase. Findings. This study examined the case of an overhead crane with the foundation affected by the leakages of strong alkaline solutions from technological basins on the ground. Laboratory studies have established the components of Al2O3, Fe2O3, CaO, K2O soluble with strong alkaline solution and their share of 13,3% in the solid phase of the alluvial-diluvial loam sampled at the site. These compounds can transform into more soluble salts in a concentrated alkaline medium, which creates the conditions for the development of soil collapse and subsidence, with the chemically induced deformations being more significant in comparison to those in soils filled with a neutral pore solution. Calculations of soil subsidence and collapse with and without taking into account the chemical impact on soils under the overhead crane foundation showed that the non-uniform critical deformations of 5...10 cm leading to an unacceptable tilt between the crane columns of 0.004 can be caused only by the long-term descending seepage of an alkaline solution and leaching the alluvial-diluvial loam. The calculated deformations and tilt correlate with the appeared deformations and the tilt between the crane columns that exceeded the maximum allowed value since 2016, which affected the operating conditions for this construction. Reducing the bearing capacity of soils due to the influence of alkaline solution occurred after engineering reclamation of soils performed prior to crane operation more than two decades ago. Scientific novelty. The effect of strong alkaline solution that seeps through the upper soil layer loaded by constructions has been evaluated; the share of dissolved solid phase in the affected soil is estimated at 1-1,5%, which is in agreement with the dissolution parameters of soil influenced by strong alkaline solutions evaluated in this study and other researchers. Practical value. The results obtained can be applied for long-term predicting the operational conditions and stability of buildings constructed on soils subjected to seepage of chemically aggressive solutions.

From titania to titanates: Phase and morphological transition in less alkaline medium under mild conditions

In this work, nine products were prepared by modifying the experimental conditions (6, 12 and 18 h at 110, 135 and 160 °C) of hydrothermal treatment of starting nanoanatase in significantly less concentrated alkaline medium than usual in order to obtain a pure titanate phase. The nanocrystalline samples were characterized by XRPD, FESEM, HRTEM/SAED, EDS, TG, FT-IR, UV-Vis and BET analyses. The results revealed that the structure, texture, morphology and band gap energy of samples strongly depend on conditions of hydrothermal treatment. The intensification of hydrothermal treatment significantly increases the solubility of TiO2 promoting the changes in morphology from nearly spherical titania nanoparticles to elongated titanate nanosheets. The single titanate phase was obtained after energetically the most intensive treatment, i.e. 18 h at 160 °C. The step-by-step optimization was thus necessary to finally distinguish the titanates from titania in terms of structural and spectral properties and to finally allow the clarification of long-standing confusion between titania and titanates. The obtained single titanate phase was furtherly used to fabricate a humidity sensor, which showed remarkably rapid response and quick recovery time.

Facile and controlled synthesis of FeCo nanoparticles via a hydrothermal method

Magnetic FeCo alloy nanoparticles have been synthesized by reduction of FeSO4 and CoCl2 with hydrazine in concentrated alkaline media via a hydrothermal route. The size could be controlled by synthetic conditions such as reaction time and temperature, respectively. The obtained samples were characterized by XRD, SEM, TEM, and VSM techniques. Magnetic investigations show the ferromagnetic behavior with saturation magnetization higher than 148.2 emu/g and maximum coercivity up to 411.0 Oe at room temperature. The present method is simple, inexpensive, surfactant-free, and may stimulate technological interests. Such FeCo alloy nanoparticles may have potential applications in biomedical field and magnetic storage devices.

Low-cost synthesis and utilization in mini-tubular electrodes of nano PbO 2

The aim of this work was to explore the possibility of using nano PbO 2 in commercial type tubular lead-acid battery positive electrodes. In that prospect, nanosized αPbO 2 and βPbO 2 have been synthesized at room temperature by a low-cost solution technique involving the chemical oxidation of lead nitrate with ammonium persulfate in concentrated alkaline medium. Mini-tubular electrodes were then prepared using the same type of gauntlet as the one used in commercial tubular electrodes. We show that the capacity and the cycling stability of the tubular electrode highly depend on the sulfuric acid concentration in the electrolyte and on the lead dioxide surface area. A percentage of utilization higher than 45% of the active mass with an excellent cycling stability was obtained when our nano βPbO 2 was used as active material in a diluted H 2SO 4 electrolyte.

New Spinel Cobalt Oxides, Potential Conductive Additives for the Positive Electrode of Ni−MH Batteries

Temperature plays a key role in the formation of the cobalt-based conductive network at the positive electrode of alkaline batteries during the first charge. Electrodes pasted with CoO were oxidized in various concentrated alkaline media, in order to understand the phenomena involved. In these conditions, the experiments show the formation of a Co3O4 type phase with defects. The presence of lithium in the electrolyte is proven to play an important role in the conductivity of the synthesized phases. Especially in 2.5 M LiOH, a pure phase is isolated that has a spinel structure close to Co3O4 but containing H and Li. This phase is shown to be a good conductor and is also observed in (KOH, NaOH, LiOH) ternary industrial electrolyte. It could hence take part to the improvement of the properties of nickel electrodes observed when the beginning of the first charge is performed at high temperature.

Potential dependence of cuprous/cupric duplex film growth on copper electrode in alkaline media

The duplex oxide film potentiostatically formed on copper in concentrated alkaline media has been investigated by XRD, XPS, negative-going voltammetry and cathodic chronopotentiometry. The interfacial capacity was also measured using fast triangular voltage method under quasi-stationary condition. The obvious differences in the thickness, composition, passivation degree and capacitance behavior were observed between the duplex film formed in lower potential region (−0.13 to 0.18V versus Hg|HgO electrode with the same solution as the electrolyte) and that formed in higher potential region (0.18–0.60V). Cuprous oxides could be formed and exist stably in the inner layer in the both potential regions, and three cupric species, soluble ions and Cu(OH)2 and CuO, could be independently produced from the direct oxidation of metal copper, as indicated by three pairs of redox voltammetric peaks. One of the oxidation peaks appeared only after the scan was reversed from high potential and could be attributed to CuO formation upon the pre-accumulation of O2− ions within the film under high anodic potentials. A new mechanism for the film growth on the investigated time scale from 1 to 30min is proposed, that is, the growth of the duplex film in the lower potential region takes place at the film|solution interface to form a thick Cu(OH)2 outer layer by field-assisted transfer of Cu2+ ions through the film to solution, whereas the film in the higher potential region grows depressingly and slowly at the metal|film interface to form Cu2O and less CuO by the transfer of O2− ions through the film to electrode.

Microstructural characterisation of geopolymers synthesised from kaolinite/stilbite mixtures using XRD, MAS-NMR, SEM/EDX, TEM/EDX, and HREM

When crystalline aluminosilicates partially dissolve in a concentrated alkaline medium, an amorphous geopolymeric gel is formed interspersed with undissolved crystalline particles. Some aluminosilicates dissolve more readily than others to give an equilibrium ratio of aluminium to silicon in the gel. In this case study, kaolinite and stilbite mixtures were used to investigate the relative reactivity of different minerals when present in different ratios. XRD and 29Si and 27Al MAS-NMR were used to determine when a specific mineral was completely transferred into the gel phase. Electron diffraction using transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HREM) were employed to establish the amorphous nature of the gel phase. Scanning electron microscopy (SEM)/energy dispersive X-ray (EDX) and TEM/EDX were then used to determine the composition of the gel. By using simple mass balance assumptions, the quantity of gel and the extent of partial dissolution of an aluminosilicate could then be calculated. It was found that a geopolymer containing a higher weight percentage of CaO in its gel, a lower ratio of (average surface area)/gel, and where the undissolved crystalline particles have a higher hardness had higher mechanical strength. The method developed in this paper is also applicable to other cementitious materials.

Electrochemical measurement of the oxygen diffusivity and solubility in concentrated alkaline media on rotating ring-disk and disk electrodes—application to industrial chlorine-soda electrolyte

The measurement of oxygen transit time from the disk to the ring of a rotating ring-disk electrode has been used for the oxygen diffusivity determination. The oxygen solubility has then been deduced from the limiting current measure in quasi-steady state oxygen reduction voltammetry. The method validation has been done for a 1 M NaOH solution at 25°C. Its use in the case of industrial electrolytes, 11.1 M (33 wt.%) NaOH at 25 and 80°C for which no literature data are available, has then been undertaken; the oxygen solubility is 72 times smaller than in 1 M soda at 25°C.

A new Mg0.9Y0.1Ni hydride forming composition obtained by mechanical grinding

Abstract We report on the synthesis of an electrochemically active Mg0.9Y0.1Ni polynanocrystalline phase by mechanical alloying. This alloy presents an initial capacity of 323 mAh/g that decreases upon cycling to reach a stable value of 220 mAh/g after 30 complete charge/discharge cycles (e.g. 62% capacity retention). Such an increase in capacity retention with respect to pure MgNi alloy (62% instead of 24%) is due to the addition of yttrium that enhances the resistance of the alloy against corrosion in concentrated alkaline media.