Nickel Hydroxide Thin Films Research Articles

Conducting Nickel Hydroxide Thin Film on Molybdenum Disulfide – Reduced Graphene Oxide Composite Electrode for Simultaneous Detection of Uric Acid, Dopamine and Ascorbic Acid

AbstractHerein we report the fabrication of a simple electrochemical sensor based on an electrode containing reduced graphene oxide and molybdenum disulphide (RGO/MoS2) as a conducting film onto the glassy carbon electrode (GCE) via a drop dry method to form GCE‐RGO/MoS2. The surface (GCE‐RGO/MoS2) was further modified with nickel hydroxide thin film using electrodeposition method to form GCE‐RGO/MoS2/Ni(OH)2. The materials and modification steps were thoroughly characterized using microscopy and spectroscopy methods. The composite electrode, GCE‐RGO/MoS2/Ni(OH)2, showed excellent electrocatalytic potential separation for the detection of dopamine, uric acid, and ascorbic acid. The electrocatalytic oxidation peak potentials were at 3 mV, 157 mV and 303 mV for AA, DA and UA, respectively. The composite electrode was also selective towards the determination of ascorbic acid (AA), dopamine (DA), uric acid (UA), and simultaneously in mixture of analytes. The low detection limits for AA, DA and UA were 1.17 μM, 0.15 μM and 1.15 μM, respectively. The composite electrode was applied for the detection of AA, DA and UA in spiked newborn calf serum samples with high percentage recoveries ranging from 96.6–100.8 % for AA, 92.8–104.2 % for DA and 99.4–102.3 % for UA.

Preparation of electrochromic nickel hydroxide (II) thin film by drying sol obtained by dialysis of solution with precipitate formed from nickel nitrate aqueous solution with ammonia and sorbitol

Preparation of electrochromic nickel hydroxide (II) thin film by drying sol obtained by dialysis of solution with precipitate formed from nickel nitrate aqueous solution with ammonia and sorbitol

Electrochemical deposition of n-type semiconducting nickel hydroxide thin films

Nickel hydroxide (Ni(OH)2) is a wide bandgap semiconductor with a bandgap energy of 3–3.5 eV, but the use of Ni(OH)2 as a semiconductor is still limited. In this study, Ni(OH)2 thin films were synthesized on indium tin oxide (ITO) coated glass substrates by electrochemical deposition and subsequent annealing in water vapor at 180 °C. The as-deposited Ni(OH)2 films were amorphous α-Ni(OH)2 intercalated with water and nitrate molecules. Nanocrystallites of β-Ni(OH)2 were formed in the films during annealing in water vapor at 180 °C. The content of β-Ni(OH)2 nanocrystallites increased with increasing annealing time. The as-deposited and annealed Ni(OH)2 films exhibited an n-type photo response in photoelectrochemical measurements. The resistivity of the annealed films was about 1 × 104 Ωcm. This resistivity value was one order of magnitude lower than that of the as-deposited film. The Ni(OH)2/NiO/ITO heterostructure was fabricated by depositing Ni(OH)2 on nickel oxide. The n-Ni(OH)2/p-NiO/ITO heterostructure diode exhibited clear rectification behavior.

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.

Electrochemical transformations of polymers formed from nickel (II) complexes with salen-type ligands in aqueous alkaline electrolytes

The polymeric nickel complexes with salen-type ligands can serve as useful materials for a range of applications, including catalytic systems and energy storage devices. Despite the fact that electrochemical properties of such complexes were investigated in detail in non-aqueous solutions, there has still remained scarce information about their behavior in aqueous systems. This work is devoted to studying such properties of poly[Ni(salen)] films in aqueous alkaline electrolytes. By combination of electrochemical methods with X-ray photoelectron and Raman spectroscopy it was shown that the redox transformations observed result in ligand exchange and formation of nickel hydroxide thin films deposited on the working electrodes. The obtained material consists of uniformly distributed nanoparticles with the characteristic size of about 10 nm. Catalytic activity of the produced modified electrodes in reactions of ethanol and methanol oxidation, as well as their ability to be charged and discharged reversibly for more than 1000 cycles, makes them promising materials for applications in catalytic and energy storage devices.

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.

Electrochemical Analysis of Optical Switchable Filter with a NiO Thin Film for High-Performance Incubators

We report an optical switchable light filter fabricated from all solid-state materials for use in preterm infant incubators. The nickel oxide (NiO) thin film in the filter was fabricated by magnetron sputtering. Conventional NiO thin films are often dipped in a solution to produce a nickel hydroxide thin film; however, our as-prepared film was stored in a thermostat/humidistat bath at 50 °C and 80% relative humidity to create the nickel hydroxide thin film instead, according to the electrochromic (EC) principle. The properties of the NiO thin film were also investigated. The optical switchable light filter also contained a W-Ir-O thin film, because the widely used WO3 thin film shows an unsuitable EC color change to dark blue. The W-Ir-O thin film did not absorb the longer wavelengths in the visible range, which is required for incubators. The optical switchable light filter containing the NiO thin film changed between pale yellow and dark yellow when a voltage was applied. The optical switching speed from the pale yellow to dark yellow state was around 60 s, and the reverse process was around 60 s. The fabrication of filters with a suitable color change for incubators requires further investigation.

Impedimetric non-enzymatic glucose sensor based on nickel hydroxide thin film onto gold electrode

A non-enzymatic glucose sensor based on a thin layer of nickel immobilized on a gold electrode (EAuNi(OH)2) was used to perform impedimetric determination of glucose. The electrodeposition solution, composed of 0.010M Ni(NO3)2·6H2O and 1M of chloride, allows only one active catalyst (NiOOH) to be present on the gold electrode surface after activation with 0.1M KOH.Electrochemical oxidation of glucose on EAuNi(OH)2 electrode was evaluated by Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) in the concentration range of 0–14.8mM of analyte. Ip/v1/2 vs scan rate graph shows a typical catalytic behavior by EAuNi(OH)2 toward glucose oxidation. Measurements in the presence of possible interfering species (ascorbic acid, uric acid, dopamine) did not affect the response of the analyte of interest.EIS offers good sensibility and selectivity for the glucose detection by non-enzymatic glucose sensor as an alternative to conventional methods. A single-frequency impedance method is proposed as transduction principle. For that, the parameters of complex impedance (module, phase, real and imaginary impedance) at each frequency were evaluated in function of glucose concentration and in terms of correlation coefficient. These analyses show a better linear response for the module of impedance (|Z|) in the range of 0–2mM of glucose at 0.1Hz (R2=0.984) with a slope of 484.7ΩmM−1 of glucose. Finally, EAuNi(OH)2 was successfully applied to the assay of glucose in blood samples.

Electrochromic Properties of Nanoporous α and β Nickel Hydroxide Thin Films Obtained by Chemical Bath Deposition

Nickel hydroxide nanoporous electrochromic thin films were obtained by chemical bath deposition method using nickel nitrate in two different formulations. In one case, ammonium hydroxide controlled the precipitation of the β-Ni (OH)2 phase through the formation of coordination compounds. In the second case, the decomposition of urea yielded the α-Ni (OH)2 phase. After thermal annealing in air in between 250 and 300 °C, the electrochromic behavior of the films was examined by cyclic voltammetry and single wavelength transmittance. The optical contrast and structural transformations between colored and bleached states of the samples were studied by ex-situ optical transmittance, X-ray diffraction, as well as Raman and infrared reflectance spectroscopies. The α-Ni (OH)2 films showed higher optical contrast and reversibility, properties associated with their porous morphology which is revealed by scanning electron microscopy studies.

Influence of substrate carboxylation on morphology of Ni(OH)2 thin film

Cellular structure nickel hydroxide thin film was obtained by hydrothermal method. The influence of substrate pretreatment and hydrothermal temperature on the morphology and microstructure of Ni(OH)2 thin film was investigated by means of X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The results indicated that the Ni(OH)2 thin film was of multilayer cellular structure, in which plate-like β-Ni(OH)2 crystals stood on the carboxylated substrate vertically and connected with each other. The carboxylation pretreatment of glass substrate could enable carbochains to play an important template role in the Ni(OH)2 thin film growth process, which was the key to the cellular structure of Ni(OH)2 thin film. Higher hydrothermal temperature could improve the degree of crystallinity of Ni(OH)2 crystal, but the temperature exceeding 200°C would damage the cellular structure.

The role of ions and reaction sites for electrochemical reversible charge cycling in mesoporous nickel hydroxides

Layered nickel hydroxide thin films with mesoporous structure were prepared on ITO substrates by a facile chemical bath deposition method. The electrochemical properties of the nickel hydroxide/oxyhydroxide films were investigated in both potassium hydroxide and lithium perchlorate in propylene carbonate electrolytes. We show that the high reversible charge cycling capability of the material is enabled by the redox reaction involving hydroxyl ions, especially in the oxidative cycle. Li ion reversible charge cycling requires available reaction or adsorption sites that can be provided by sub-stoichiometry or defective films. Raising the defect concentration, the cyclic reversibility is shown to increase by ∼5 times. The effects of intercalated water in the interlayers are also discussed. We show that the presence of water in the interlayers can lead to a passivating reaction during the charge cycling and also cause optical efficiency losses through unwanted charge trapping.

Redox, pH sensing and Electrolytic Water Splitting Properties of Electrochemically Generated Nickel Hydroxide Thin Films in Aqueous Alkaline Solution

Redox, pH sensing and Electrolytic Water Splitting Properties of Electrochemically Generated Nickel Hydroxide Thin Films in Aqueous Alkaline Solution

Effects of deposition temperature and annealing temperature on the morphology and electrochemical capacitance of Ni(OH)2 thin films

In this paper, we report 3D nickel (II) hydroxide thin films with porous nanostructures prepared on Ni foam by direct current electrodeposition from aqueous solution of Ni(NO3)2 through basic chemicals. The effect of deposition temperature on Ni(OH)2 thin film morphology is examined by field emission scanning electron microscopy, which is found to have significant influence on capacitance performance of Ni(OH)2 thin films. Moreover, the effect of annealing temperature on electrochemical capacitance and long-time stability of Ni(OH)2 thin films is investigated. An optimum-specific capacitance value of 2,447 farads g−1 is obtained for Ni(OH)2 thin film deposited at 20 °C and annealed at 100 °C.

Lithium-driven electrochromic properties of electrodeposited nickel hydroxide electrodes

Nanostructured nickel hydroxide thin film was prepared by cathodic electrodeposition in room temperature followed by annealing process at 250°C. The annealed nickel hydroxide thin film exhibited good lithium-driven electrochromic properties without any activation process. The as-deposited nickel hydroxide thin film was transparent while the annealed one showed brownish color. The annealed thin film could be used as counter electrode coupled with tungsten oxide thin film electrode. A complementary electrochromic device in the form of glass/FTO/WO3/Li+–PVB/NiO/FTO/glass was also demonstrated in the present study.

Electrochromic and electrochemical properties of amorphous porous nickel hydroxide thin films

Nickel hydroxide films were prepared using the chemical bath deposition (CBD) technique. The amorphous nature of the films was confirmed by X-ray diffraction measurements. X-ray photoelectron spectroscopy (XPS) measurements showed that the films exhibited nickel hydroxide nature. The porosity of the films was studied using optical measurements. The electrochromic properties of the porous nickel hydroxide layers were investigated, using cyclic voltammetry, chronoamperometry, in situ transmittance, UV–vis spectroscopy, and impedance spectroscopy. The change in the optical density (ΔOD) was found to be 0.79 for the as-deposited nickel hydroxide films, whereas it is 0.53 and 0.50 for the films annealed at 150 °C and 200 °C, respectively. The in situ transmittance and chronoamperometry curves revealed that the annealed films had a very fast colouration ( t c < 290 ms) and decolouration ( t b < 130 ms). The measured colouration efficiencies range between 30 and 40 cm 2/C. The impedance measurements revealed the faster colouration and good electrochromic properties for the annealed nickel hydroxide films.

ChemInform Abstract: Improvement in Electrochromic Stability of Electrodeposited Nickel Hydroxide Thin Film.

The electrochromic nickel hydroxide thin film was anodically deposited from an aqueous solution. The effect of solution temperature, postheat-treatment temperature, and addition of cadmium on the electrochromic behavior (color/bleach durability cycle, response time, and coloration efficiency of the nickel hydroxide films in NaOH) were investigated. A significant increase in the color/bleach durability cycle from 500 (for the as-deposited film) to more than 5000 cycles (for the heat-treated film) was observed. The addition of cadmium increased the utilization of the active materials. It was found that the coloration efficiency was 40 cm{sup 2}/C and coloration and bleaching response time were 20 to 30 s and 8 to 10 s, respectively. The change in the electrochromic properties with heat-treatment temperature is discussed based on the physical and electrochemical analysis.

Platinum nanoparticle-modified electrodes, morphologic, and electrochemical studies concerning electroactive materials deposition

The present work describes the synthesis of platinum nanoparticles followed by their electrophoretic deposition onto transparent fluorine-doped tin oxide electrodes. The nano-Pt-modified electrodes were characterized by voltammetric studies in acidic solutions showing a great electrocatalytic behavior towards H+ reduction being very interesting for fuel cell applications. Morphological characterization was performed by atomic force microscopy on different modified electrodes showing a very rough surface which can be tuned by means of time of deposition. Also, nickel hydroxide thin films were galvanostatically grown onto these electrodes showing an interesting electrochemical behavior as sharper peaks, indicating a faster ionic exchange from the electrolyte to the film.

Structural, electrochemical and optical properties of NiO xH y thin films prepared by electrochemical deposition

Nickel hydroxide thin films were deposited on SnO 2/glass substrates by electrochemical deposition. The structural, electrochemical and optical properties of nickel hydroxide films were investigated using XRD, STM, cyclic voltammetry and spectrometer, respectively. The mechanism of the chemical deposition process was discussed. The deposition rate of the films as a function of molar concentration of NH 4OH was also obtained in this study. γ-NiOOH was synthesized in the colored films. The maximum value of optical density change was found at 460 nm in visible spectrum.

Characterization of honeycomb-like “β-Ni(OH) 2” thin films synthesized by chemical bath deposition method and their supercapacitor application

Nanostructured nickel hydroxide thin films are synthesized via a simple chemical bath deposition (CBD) method using nickel nitrate Ni(NO 3) 2 as the starting material. The deposition process is based on the thermal decomposition of ammonia-complexed nickel ions at 333 K. The structural, surface morphological, optical, electrical and electrochemical properties of the films are examined. The nanocrystalline “β” phase of Ni(OH) 2 is confirmed by the X-ray diffraction analysis. Scanning electron microscopy reveals a macroporous and interconnected honeycomb-like morphology. Optical absorption studies show that “β-Ni(OH) 2” has a wide optical band-gap of 3.95 eV. The negative temperature coefficient of the electrical resistance of “β-Ni(OH) 2”, is attributed to the semiconducting nature of the material. The electrochemical properties of “β-Ni(OH) 2” in KOH electrolyte are examined by cyclic voltammetric (CV) measurements. The scan-rate dependent voltammograms demonstrate pseudocapacitive behaviour when “β-Ni(OH) 2” is employed as a working electrode in a three-electrode electrochemical cell containing 2 M KOH electrolyte with a platinum counter electrode and a saturated calomel reference electrodes. A specific capacitance of ∼398 × 10 3 F kg −1 is obtained.

Chemically deposited nanocrystalline NiO thin films for supercapacitor application

A chemical synthesis process for the fabrication of NiO is described. In the present work, we report a chemical route for preparation of nickel hydroxide thin films on the glass substrate from solution containing Ni (2+) ions and ammonia. The deposition process based on the thermal decomposition of ammonia complex with nickel ions at temperature 333 K. As-prepared films were annealed at 623 K in air for 2 h to remove hydroxide phase and used for structural, surface morphological and optical characterizations. It was found that after annealing β-phase of Ni(OH) 2 was transformed to a cubic phase structured NiO. Honeycomb like surface morphology of “β-Ni(OH) 2” films was merged and resulted in decrease in porosity after annealing. A red shift in band gap energy was observed after annealing. The capacitive characteristics of the films deposited on steel substrate were investigated in KOH electrolyte using cyclic voltammetry. The supercapacitive properties of NiO were strongly affected by scan rate, concentration of electrolyte and deposited mass of the material. The maximum specific capacitance of 167 F g −1 was obtained in 2 M KOH electrolyte.