Nickel Hydroxide Films Research Articles

Influence of H2 on the properties of NiOxHy thin films deposited by reactive direct current magnetron sputtering for electrochromic devices

This study aims to optimize the deposition condition of Nickel hydroxide (NiOxHy) films for electrochromic devices by adjusting the H2 gas concentration during the reactive direct current magnetron sputtering. The influence of H2 content on the crystallinity, chemical composition, optical properties, and electrochromic behavior of the NiOxHy films was thoroughly investigated. In the absence of H2 gas in the sputtering system, the Nickel oxide (NiOx) film was obtained as confirmed by the X-ray diffraction results. However, introducing the H2 gas resulted in the formation of NiOxHy film, accompanied by a decrease in the film crystallinity. Fourier transform Infrared spectra were employed to confirm the presence of hydroxyl groups in the as-deposited NiOxHy films. X-ray photoelectron spectroscopy was employed to examine the influence of H2 content on the optical properties of the NiOxHy film. Additionally, it offered valuable insights into the film's chemical composition during the transition from a dark to a transparent state. Our findings revealed that increasing the H2 gas content enhanced the transmittance of NiOxHy films. Here, the optimal H2 flow ratio of 50 % was found to yield a high transmittance of 77.43 % (T550) along with the highest charge density, an optical density changed value of 0.84, and a coloration efficiency value of 83.67 cm2/C. These findings clearly illustrate the substantial influence of H2 concentration on the properties of NiOxHy films, particularly in relation to their application in electrochromic devices.

A highly sensitive and ecofriendly assay platform for the simultaneous electrochemical determination of rifampicin and isoniazid in human serum and pharmaceutical formulations

Simple fabrication of an electrochemical sensor for simultaneous determination of rifampicin and isoniazid based on electrochemical modification of SPCE surface with reduced graphene oxide and nickel hydroxide film (Ni(OH)2/rGO/SPCE) without using toxic chemical agents.

Role of different atmosphere gasses during annealing in chemical-solution-deposition NiO thin films processing

Thermally processed nickel oxide (NiO) thin films were synthesized from nickel hydroxide films obtained by chemical solution deposition. Potential applications derived from electronic properties were studied by thermally treated thin films under two controlled annealing atmospheres. The NiO thin films with thicknesses between 160 and 192 nm and a nanowall-like morphology were obtained. Amorphous thin films with high optical transmittance in the visible region of around 85 % and ∼3.7 eV bandgap energy were obtained. The chemical composition of the NiO films was determined by X-ray photoelectron spectroscopy (XPS), which confirmed that the films were indeed composed of NiO after thermal treatment. The electrical properties were acquired through the Hall effect technique. The NiO films exhibit a p-type conductivity; the highest carrier concentration is 5×1015 cm−3. Mobility up to 11 cm2∙V−1∙S−1 and low resistivity of 9×102 Ω∙cm. These properties are suitable for applications in transparent electronic devices.

Multiple‐Scale Probing of Intrinsic Active Sites and Reaction Kinetics in Processable Cation‐Inserted Nickel Hydroxide Films

AbstractNanoplate‐shaped Ni(OH)2 with numerous exposed active sites hold much promise for high‐performance energy storage devices. However, restricted by the wide band gap, which leads to a low concentration of charge carrier, the energy barrier of electron mobility in lattice plane is high, further inhibiting the electron transfer and their practical application. Here, several unique processable nickel‐based hydroxide films are constructed via the cation‐inserted strategy to probe the intrinsic relationship between component and electronic micro‐structure. Benefiting from the component‐driven effects, the concentration of charge carrier at the lattice plane can be accumulated after injecting heterogeneous cations, and the fastened dynamics process can be realized and confirmed by multiple real‐time operando techniques. Meanwhile, the more well‐matched Co core rather than Mn core in Ni(OH)2 is also certified. Finally, the CoNi(OH)2 electrode achieves 623 C g–1 @1 A g–1 without any conductivity additives and binders, which is nearly threefold that of pristine Ni(OH)2. This work clarifies the critical role of inserted cations, and corresponding electron and electrolyte ion transfer across the matrix, thus enabling a better guideline for Ni(OH)2‐based energy storage/conversion systems.

Visible Light Enhanced Electrocatalysis of Methanol Oxidation and Hydrogen Evolution on Nanoporous Nickel Hydroxide Film

In this work, high-surface-area nanoporous nickel hydroxide (Ni(OH)2) was one-pot electrodeposited by a dynamic hydrogen bubble template formed through facile water electrolysis. The as-obtained nanoporous Ni(OH)2 exhibited a visible light response semiconducting behavior with an optical band gap of 2.17 eV, as estimated by the Tauc methodology. The Mott-Schottky plot estimated the valence band (EVB) and conduction band (ECB) energies of the nanoporous Ni(OH)2 to −6.14 and −3.97 eV, respectively. The effects of visible light irradiation of nanoporous Ni(OH)2 film on methanol oxidation (MOR) and hydrogen evolution (HER) reactions were investigated in alkaline solutions. Compared to data obtained under dark, the potentiodynamic linear sweep voltammetry (LSV) and potentiostatic chronoamperometry (CA) results revealed remarkable enhancements in MOR and HER current responses using nanoporous Ni(OH)2 electrode under visible light, reaching up to 59% and 153%, respectively. The superior photoelectrochemical performances of the nanoporous Ni(OH)2 film toward MOR and HER were attributed to the high surface area, narrow band gap, low electron/hole recombination, and elevated light absorption efficiency induced by multiple reflection and scattering of incident light. In sum, the high photoelectrocatalytic performances of the nanoporous Ni(OH)2 combined with the low material cost and facile production make it promising for various electrochemical reactions with better reaction rates under visible light irradiation.

Green Process for Preparation of Nickel Hydroxide Films and Membranes

Nickel hydroxides have numerous applications including as battery electrodes, electrochromic devices, electrochemical sensors, and supercapacitors and in such processes as photocatalysis, electrocatalysis, and electrosynthesis. A simple solution growth process for production of beta-Ni(OH)2 has been developed. The process involves dissolution of nickel hydroxide powders in concentrated ammonia to form [Ni(NH3)6](OH)2. If ammonia is allowed to evaporate from the resulting solution, the dissolution process is reversed and crystalline films of beta-Ni(OH)2 are deposited that consist of closely packed micron-sized clumps of thin plates. Addition of sodium aluminate to the solution makes it possible to also prepare alpha nickel hydroxide as free standing membranes at air–water interface. The overall procedure can be described as a green process since it eliminates the environmental burden of by-product production because Ni(OH)2 is simply dissolved and transformed into the desired material without producing waste salts such as ammonium nitrate or ammonium chloride that would be produced by a conventional precipitation approach for Ni(OH)2 membrane or film preparation.

Simple deposition of mixed α, β-nickel hydroxide thin film onto nickel foam as high-performance supercapacitor electrode material

Here, uniform thin nanosheets’ film of mixed α- and β-Ni(OH)2 phases was cathodically electrodeposited onto nickel foam support and the fabricated electrode was utilized as binder-free electrode for supercapacitor applications. An additive-free aqueous electrolyte of 0.05 M nickel nitrate was used as the deposition bath, where the hydroxide film was prepared with only applying direct current of 10 mA/cm2 in a two-electrode system while a uniform electrical field was established through using two counter electrodes parallel to nickel foam cathode. The morphology, crystalline phase and also specific surface area of the deposited nickel hydroxide film onto Ni foam were analyzed using field-emission scanning electron (FE-SEM) and X-ray diffraction (XRD) techniques as well as BET and FT-IR spectroscopy. These analyses proved that a mixed alpha and beta phases of Ni(OH)2 with uniform nanosheets’ morphology are grown onto the nickel foam cathode. The electrochemical investigations using CV, GCD and electrochemical impedance spectroscopy (EIS) manifested the designed electrode provides specific capacitance of 2143 F g−1 at a current density of 0.5 A g−1 with high rate capability of 65% by increasing the current density from 0.5 to 20 A g−1 as well as 90% and 74% cycling stability at the current densities of 5 and 15 A/g, respectively. The excellent electrochemical performance of the as-prepared electrode is ascribed to the simultaneous deposition of both α and β phases through using a facile electrochemical deposition method. The presence of α and β phases guarantees the high specific capacitance and high cycling stability of the prepared electrode, respectively.

Study of the Mn2+ ions influence in the deposition electrolyte on the electrochromic properties of obtained Ni(OH)2 films

An attempt was made to co-deposit nickel and manganese hydroxide films to be used as anodic electrochrome. Cathodic template method with polyvinyl alcohol was used for this. Deposition was conducted in the galvanostatic regime from the solution containing nickel and manganese nitrates in an 8:1 molar ratio.As a result of the work, two films were deposited: one from pure nickel nitrate and one from nickel and manganese nitrate solutions. Analysis of the synthesized films, revealed significant differences in structural, electrochemical and optical properties. The film deposited from the pure nickel nitrate solution was composed of a single α-like form Ni(OH)2. On the other hand, the film deposited from the manganese-containing solution was composed of two phases. Morphology comparison revealed that the surface of the undoped film is rather flat, with small bumps up to 160 nm. The Mn-doped film had many ridges of up to 1200 nm.Electrochemical properties of the film deposited in the presence of Mn were inferior to the film deposited from the pure solution. This is manifested in lower current densities and lower specific capacities of oxidation and reduction processes. Electrochromic properties of the film deposited in the presence of manganese were somewhat worse as well.A mechanism explaining the decrease of specific characteristics of the film in the case of using such deposition method was suggested. The mechanism lies in the formation of the second manganese-containing phase. This phase is rather inert and decreases the content of electrochemically active Ni(OH)2 in the film.The authors also suggested possible uses of the resulting structure

Synthesis of nanostructured Nickel compounds on conductive metallic substrates

Abstract Nickel hydroxide, oxide, and sulfide films were synthesized on conductive Ni metallic substrates by solid-vapor reactions, calcination and hydrothermal methods. The synthesized films were characterized by XRD, XPS, FE-SEM, UV–Vis Spectroscopy and Cyclic Voltammetry (CV). The morphological analyses of Ni(OH)2 and NiO films showed flower-like nanostructures with thicknesses from 20 to 40 nm; meanwhile the NiS films exhibits nano-granular morphology. All films showed high optical reflectance in the visible region and a sharp absorption edge below 400 nm. The specific capacitance of the Nickel compound ranges from 134 to 311 mF cm−2 (at 20 mV s−1) suggesting potential as conductive electrodes for energy storage and electrochemical conversion cells.

Optical properties of NiOOH films in formaldehyde solutions

Films of nickel hydroxide have been obtained by electrodeposition. The analysis of interferograms, optical spectra, XRD analysis and the SEM of the obtained films showed that the deposition of films with ~ 10−5 mol/L PcNi(SO3Na)4 in the Ni(NO3)2 solution helps to control the formation of uniform Ni(OH)2 films with dominance structure of α-Ni(OH)2. The studies of the kinetics of optical changes of NiOOH films in aqueous formaldehyde solutions showed that due to the reaction of NiOOH with formaldehyde, its color changes. It was established that the dependence of the rate of change of light transmittance, ΔT/Δt, on the concentration of formaldehyde is linear in the range of 0.5–20 mmol/L. An analysis of cyclic plots of electrochemical oxidation of Ni(OH)2 to NiOOH and its reduction by the action of formaldehyde showed that the formaldehyde concentration of more than 22 mmol/L can be determined from the absolute value of light transmittance. It was established that an dominance of structure of α-Ni(OH)2 and decrease the thickness of the films to ~ 150 nm contributes by oxidation processes solutions of millimolar concentrations formaldehyde.

A study of electrochromiс Ni(OH)2 films obtained in the presence of small amounts of aluminum

The research is related to the synthesis of electrochromic films of nickel hydroxide with aluminum as a dopant. Films were deposited via cathodic template synthesis in the presence of polyvinyl alcohol from solutions containing 0.01 M Ni(NO 3 ) 2 and Al(NO 3 ) 3 . Aluminum nitrate was added in different concentrations: 0.138, 0.257 and 0.550 mM. The necessary aluminum concentration was calculated based on the theoretical grounding with the use of Faraday’s law equation. All of the prepared films demonstrated electrochemical activity, and the film deposited from the solution containing 0.01 M Ni(NO 3 ) 2 and 0.138 mM Al(NO 3 ) 3 has demonstrated the best results. The film cycled reversibly with the coloration degree of – 81 %. At the same time, the film prepared under the same conditions without the dopant demonstrated the coloration degree of 75.8 %. All films deposited in the presence of aluminum had lower switching, especially bleaching, speed in comparison to the undoped reference sample. Morphology study of the prepared films revealed that the latter differs little. The film deposited in the presence of 0.138 mM Al(NO 3 ) 3 had spherical formations on its surface. It was also found that the morphology of the substrate, which was glass coated with SnO 2 :F, differed significantly from the morphology of the films deposited with and without the dopant. The film deposited from the solution of 0.01 M Ni(NO 3 ) 2 and 0.138 мМ Al(NO 3 ) 3 was confirmed to contain aluminum. The mass ratio of aluminum to nickel in the Ni–Al-138 film varied between 1:10.23 and 1:6.44.

Optimization of the deposition conditions for Ni(OH)2 films for electrochromic elements of “smart” windows

Thestudywasconductedinordertodeterminethe influenceoftwofactorsonelectrodepositionofNi(OH)2 films: concentrationofnickelnitratein the electrolyteanddrying stage between deposition and electrochemical and optical tests. For deposition, pure solutions of nickel nitrate without additives were used, so that the presence of the latter did not complicate the analysis of the data obtained.As a result, two series of films were prepared from electrolytes with nickel nitrate concentrations of 0.01, 0.1 and 1 M. The difference between the two series is the presence or absence of drying stage after deposition. Drying was conducted under mild conditions at room temperatures.Electrochemical and optical characteristics were evaluated by means of cyclic voltamperometry with simultaneous recording of changes in film transparency.As a result of analysis of the obtained data, it was found that uniform films with roughly equal thickness are obtained within the nickel nitrate concentration range from 0.01 to 0.1 M. For solutions with the nickel nitrate concentration of 1 М, deposition occurs with significant non-uniformity. A hypothesis was proposed, in which such behavior is explained by redistribution of current density over the electrode surface due to the high conductivity of the concentrated nickel nitrate solution. In turn, the redistribution of current density results in a significantly high current density on the electrode surface near the electrolyte-air boundary. Such an increase could result in shifting of the reaction front away from the electrode or formation of Ni(OH)2 with high thickness. The latter would lose contact with the electrode and fall off.It was also found that drying process has a significant effect on the structure and properties of the films. Drying process was also found to impact the appearance of nickel hydroxide films due to film cracking. It was also assumed that electrochemically deposited nickel hydroxide contains a large amount of crystal water

One-Pot Synthesis of Nanoporous Nickel Hydroxide Film as High-Performance Electrode for Asymmetric Supercapacitor

In this work, nanoporous nickel hydroxide (Ni(OH)2) films were rationally synthesized by a facile and cost-effective one-pot route. Hydrogen (H2) bubbles and hydroxide (OH−) ions simultaneously generated from water electrolysis at the cathode at appropriate potentials play a critical role of producing in-situ porous Ni(OH)2 films in a solution of nickel salt. The induced H2 bubbles served as dynamic templates to create porosity and OH− ions as a precipitant to crystallize Ni(OH)2. At optimal conditions, porous Ni(OH)2 films with pores as small as ∼2 nm were directly formed, as verified by N2 adsorption/desorption measurements. The as-obtained nanoporous Ni(OH)2 films exhibit high specific capacity >739 C/g at the charge/discharge current density of 1 A/g and mass loading of 0.6 mg/cm2 in three-electrode configuration; and energy and power densities as high as 152 Wh/kg and 13.5 kW/kg at current density of 15 A/g in two-electrode asymmetric supercapacitor. This straightforward, low-cost, and highly-efficient synthesis of nanoporous Ni(OH)2 films is potentially useful for capacitor industry as well as other application fields. In addition, the water electrolysis method may be applied to the direct formation of other porous metal hydroxides.

Influence of electrodeposition temperature in the electrochemical properties of Ni(OH)2: An experimental and theoretical study

In the present work, electrodeposition different temperatures are employed to obtain nickel hydroxide films on titanium substrate. The influence of this parameter on the electrochemical properties of the material is studied. The films are morphologically and structurally characterized using techniques of X-Ray Diffraction and Scanning Electronic Microscopy. The density functional theory (DFT) calculations are performed to study the effect of strain applied along the Ni(OH)2 unit cell and electron density maps are performed to relate with electrochemical properties. For the electrochemical characterization are used cyclic voltammetry, galvanostatic charge- discharge and electrochemical impedance spectroscopy techniques. The films deposited at 10 °C, development a structure which favors the charge storage, both in those more accessible surfaces, and in those of more difficult access, by electrolyte ions. This fact is in correspondence with the DFT results for this temperature that suggests an improvement in the material electrochemical properties, showing a high capacitance value (2549 F g1).

Influence of the deposition temperature on the properties of electrodeposited nickel hydroxide films: A study performed by EIS

In the present work, electrodeposition at different temperatures was employed to obtain nickel hydroxide films onto titanium substrates. The influence of the temperature on the electrochemical properties of the as-prepared films was studied. The results were discussed in capacitance and power complex terms by using the electrochemical impedance spectroscopy technique. It was obtained that the relaxation time constant changed from 6.94 s and 1.49 s, as the electrodeposition temperature increases from 5 to 25 °C, while the capacitance decreased from 866 to 214 mF cm−2. The results obtained suggest that, through the control of the deposition temperature, films of nickel hydroxides, with potential applications as material for electrodes, in different energy and power requirements can be synthesized.

A study of the effect of tungstate ions on the electrochromic properties of Ni(OH)2 films

Thin films of nickel hydroxide were prepared using the cathodic template method and were tested in different electrolytes. The electrolytes were 0.1 M KOH and 0.1 M KOH with the addition of 0.1, 0.3 and 1 mM K2WO4. The test revealed, that the presence of tungstate can have a significant effect on electrochemical and electrochromic characteristics of Ni(OH)2 films. The initial sample, cycled in 0.1 M KOH showed different characteristics from those cycled in tungstate-containing electrolytes: significant difference between current densities of cathodic and anodic peaks and presence of the current plateau on the cyclic voltamperometry curve. However, the initial sample demonstrated the highest coloration degree of 74 %. On the other hand, the sample showed degradation of the coloration degree past initial growth.The samples cycled in the tungstate-containing electrolyte showed better electrochemical characteristics – sharper cathodic and anodic peaks, with the lesser difference between peak values. The dynamics of the absolute coloration degree of the samples cycled in tungstate-containing electrolyte showed a constant increase. The sample tested in a solution with 1 mM tungstate had the lowest value of the absolute coloration degree – 60 %. For tungstate concentrations of 0.1 and 0.3 mM, the absolution coloration degree at the last cycle was 72 and 71 % respectively.The samples tested in a solution with tungstate additive had a significantly lower bleaching time – 40–50 s in comparison to 360 s of the sample cycled in 0.1 М KOH.A possible mechanism that explains such differences in behavior was proposed

New Interpretation of the Performance of Nickel-Based Air Electrodes for Rechargeable Zinc–Air Batteries

Rechargeable zinc–air batteries with high energy density, cycle life, and calendar life require corrosion-resistant support materials in the air electrode. Nickel-based air electrodes have shown promise in this regard as a substitute for conventional carbon-based air electrodes, but their performance in zinc–air batteries has not been studied in-depth. Specifically, the effect of the nickel (oxy)hydroxide passivating film on the electrode’s catalytic performance and durability requires investigation. To fill this research gap, a method involving electrochemical estimation of the nickel (oxy)hydroxide film capacity was used to link the growth of the film to performance losses experienced on the air electrode after battery cycling. The main cause of voltage loss was the nickel (oxy)hydroxide film growing overtop of and inside the catalyst-coated nickel aggregates. This resulted in significant activation and mass transfer losses, where the latter losses were caused by the film growing overtop of the catalyst...

Solution layer-by-layer uniform thin film dip coating of nickel hydroxide and metal incorporated nickel hydroxide and its improved electrochromic performance

In this work, we identified the problem faced by conventional successive ionic layer adsorption and reaction (SILAR) process in producing uniform nickel hydroxide films as the homogeneous precipitation reaction in water. Subsequently we proposed a novel SILAR recipe with a modified rinsing step and successfully demonstrated, for the first time, a layer-by-layer coating of uniform nickel hydroxide thin film without surface structures or agglomerated precipitates. In addition, we explored and demonstrated the capability of the proposed SILAR process in incorporating additional element such as aluminum into the nickel hydroxide film. The aluminum incorporated nickel hydroxide film shows improved electrochromic stability evidenced by reducing the degradation in coloration efficiency from 46% to 6%. The average coloration efficient is reported as 22 cm2/C and the response time is 4.5 s for bleaching and 4 s for coloration.

The electrochemical cathodic template synthesis of nickel hydroxide thin films for electrochromic devices: role of temperature

The influence of temperature on the synthesis of Ni(OH) 2 electrochromic films prepared using the cathodic template method has been investigated. The influence of deposition temperature on the morphology of nickel hydroxide films has been determined. By means of scanning electron and atomic-force microscopy, it has been established that surface morphology depends on deposition temperature. The flattest film surface corresponded to a deposition temperature of 30 °С, which indicated high optical properties. The maximum profile shift of films deposited at different temperatures was 400nM, while for the film deposited at 30 °С – 212 nM. By means of X-ray diffraction, it has been established that all films have crystal lattice similar to α-Ni(OH) 2 , with a high number of defects в . It also has been discovered that at a deposition temperature of 20–60 °С, a peak at 2q=16° appears on the diffraction pattern, the highest intensity of which corresponds to the process temperature of 30–40 °С. By means of cyclic voltamperometry and recording of transmittance changes, it has been demonstrated that nickel hydroxide film deposited at 30 °С has the best electrochemical and optical properties. A partial correlation between optical and electrochemical properties of films deposited at different temperatures has been noted.

Compositional Optimization of Alloy FexNiy(OH)2 Nanoparticles for Alkaline Electrochemical Oxygen Evolution

It has recently been demonstrated by Bell and co-authors [1] that intentional iron doping into a nickel hydroxide film causes significant enhancement in electrochemical performance for the oxygen evolution half reaction (OER) of alkaline electrolysis. A subsequent study by Boettcher and co-authors [2] demonstrated that unintentional iron doping of a nickel hydroxide catalyst occurs from ppm- to ppb-level iron contaminants in alkaline electrolytes; the iron incorporates into the nickel hydroxide structure, and causes at least an order of magnitude increase in current density. Freibel et al. subsequently demonstrated that iron may in fact be the active site of OER, with nickel hydroxide acting as a host [3]. The majority of the work thus far investigating how iron content in an FexNiy(OH)2 catalyst affects OER has been performed on thin film catalysts; Burke et al. specifically describe the need for catalyst architectures that reduce mass transport limitations and allow improved access to more active sites per unit mass of catalyst [4]. As a result, there is an interest in developing nanoscale catalysts that are composed of iron and nickel and result in greatly improved performance metrics for OER over their thin film counterparts. Here, we will present results for the optimization of a FexNiy(OH)2 nanoparticle catalyst. In this work, the nanoparticles are synthesized with an alloy morphology and the atomic ratio of iron to nickel is varied from 1:5 to 5:1. Once synthesized, the nanoparticles are evaluated in 1 M KOH that has been purified to remove any iron impurities. Electrochemical performance of this series of nanoparticle catalysts will be discussed as well as our efforts to characterize the nanoparticles with electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction. [1] M.W. Louie, A.T. Bell, An investigation of thin-film Ni-Fe oxide catalysts for the electrochemical evolution of oxygen, J. Am. Chem. Soc., 135 (2013) 12329-12337. [2] L. Trotochaud, S.L. Young, J.K. Ranney, S.W. Boettcher, Nickel-iron oxyhydroxide oxygen-evolution electrocatalysts: The role of intentional and incidental iron incorporation, J. Am. Chem. Soc., 136 (2014) 6744-6753. [3] D. Friebel, M.W. Louie, M. Bajdich, K.E. Sanwald, Y. Cai, A.M. Wise, M.-J. Cheng, D. Sokaras, T.-C. Weng, R. Alonso, R.C. Davis, J.R. Bargar, J.K. Norskov, A. Nilsson, A.T. Bell, Identification of highly active Fe sites in (Ni,Fe)OOH for electrocatalytic water splitting, J. Am. Chem. Soc., 137 (2015) 1305–1313. [4] M.S. Burke, L.J. Enman, A.S. Batchellor, S.H. Zou, S.W. Boettcher, Oxygen evolution reaction electrocatalysis on transition metal oxides and (oxy)hydroxides: Activity trends and design principles, Chemistry of Materials, 27 (2015) 7549-7558.