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.

Electrodeposited Cobalt Hydroxide Thin Films: A Comprehensive Investigation from Synthesis to Advanced Electrochemical Behavior for High-Performance Energy Storage

Electrodeposited Cobalt Hydroxide Thin Films: A Comprehensive Investigation from Synthesis to Advanced Electrochemical Behavior for High-Performance Energy Storage

ZPCC-Zn-Al-LDH surface bilayer; toward designing a durable self-healable nano-structured film with the utmost corrosion resistance

BackgroundDesigning thin films with utmost corrosion resistance stability and long-term metal protection from corrosive species attacks is the main idea of this work. Zinc phosphate conversion films are greatly exploited for improving the anticorrosion properties and surface preparation prior to organic coating application. Layered double hydroxide (LDH) thin films consist of a dense layer and a plate-shaped part, which perform the functions of the barrier and ion exchange, respectively. MethodsA bilayer conversion coating composed of a modified zinc phosphate layer and LDH crystals was fabricated on mild steel and then loaded with a glutamate corrosion inhibitor. These coatings were characterized by FE-SEM, XRD, FT-IR, and XPS methods. Significant findingsEIS results showed that log |Z|0.01 Hz reached its maximum value (6.14 Ω cm2) for the conversion coating sample loaded with inhibitor. Also, the active properties of the polyester organic coating with the introduced primer were ameliorated insofar as the total resistance of the scratched coating was obtained at around 115 KΩ cm2 after 48 h of exposure to the salty solution.

Enhancing supercapacitor performance through electrodeposition of cobalt hydroxide thin film: structural analysis, morphological characterization, and investigation of electrochemical properties

Enhancing supercapacitor performance through electrodeposition of cobalt hydroxide thin film: structural analysis, morphological characterization, and investigation of electrochemical properties

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

Growth of vertically aligned nanosheet-like structured nickel–cobalt hydroxide thin films and their electrochemical properties

Growth of vertically aligned nanosheet-like structured nickel–cobalt hydroxide thin films and their electrochemical properties

Cobalt hydroxide‐based electrodes for supercapacitors: Synthesis, characterization, and electrochemical performance optimization

AbstractDopant‐free cobalt hydroxides were synthesized via electrochemical deposition techniques, employing various precursors. The process involved preparing an aqueous electrolyte with a 0.1 M concentration of the respective precursor at ambient temperature (27°C). The synthesis of cobalt hydroxides was carried out using a two‐electrode system, with a controlled potential of 0.5 V. After the successful synthesis of dopant‐free cobalt hydroxides using the electrochemical deposition techniques with different precursors, the next step involved investigating these cobalt hydroxide electrodes. For this purpose, a three‐electrode system was utilized to analyze their cyclic voltammetry (CV), galvanostatic charge‐discharge (GCD), and electrochemical impedance spectroscopy (EIS) characteristics. Furthermore, to gain deeper insights into the properties of the cobalt hydroxide thin films, thorough examination was conducted using various techniques. X‐ray diffraction (XRD) was employed to study the crystal structure, scanning electron microscopy (SEM) to observe the surface morphology, and UV spectra to analyze the optical properties of the thin films. The investigations unveiled that the films displayed a crystalline nature with an average crystallite size of 40 nm. The morphology of the film appeared leaf‐like, and the particle size was measured to be 180 nm. Notably, the cobalt hydroxide electrodes demonstrated exceptional electrochemical performance. The specific capacitance, energy density, and power density of these electrodes were found to have average values of 1140 F/g, 142.5 Wh/kg, and 4.74 W/kg, respectively. These impressive results underscore the excellent performance and robust cycle stability of the cobalt hydroxide electrodes, making them highly promising for supercapacitor applications.

Synthesis and characterization of chitosan/polyvinyl alcohol immersed in sodium hydroxide thin film as a heterogeneous catalyst in biodiesel production

Biodiesel is a potential renewable energy source that can be used to replace fossil fuels because of its low toxicity, biodegradability, and renewability. However, biodiesel production requires long reaction times. Hence, a catalyst is needed to speed up the reaction and optimize production conditions. CS/PVA thin film catalyst immersed in NaOH has intriguing catalytic properties that can improve biodiesel conversion efficiency. In this paper, a series of chitosan/polyvinyl alcohol‑sodium hydroxide (CS/PVA-NaOH) thin films have been prepared as heterogeneous catalysts in biodiesel production. According to the FTIR spectra data, It shows that the vibrational frequency of the hydroxyl group (-OH) shifted from 3271 cm−1 to 3290 cm−1, indicating the hydrogen bond interaction between chitosan and PVA. Water uptake (45.42–218.64 %), swelling (120.63–142.99 %), porosity (62.67–243.43 %), and the durability of the thin film at pH conditions of 5–11 have been found to be the physicochemical characteristics of blended Chitosan/PVA (4/1; 3/2; 2.5/2.5; 2/3; 1/4 (v/v)). The optimal conditions for producing biodiesel were found to be around 65 °C for 90 min with an oil: methanol molar ratio of 1:7. By using a heterogeneous catalyst of CS/PVA-NaOH, the conversion efficiency from oil to biodiesel was achieved at around 95.39–99.52 %.

The spatial structures of iron oxide formed on an ordered Pt(111) electrode in pH 3 sulfate and chloride media

Platinum (Pt) electrodes modified with iron (Fe) have been used as electrocatalysts to split water, to reduce oxygen, and to oxidize methanol. The current study employed cyclic voltammetry and in situ scanning tunneling microscopy (STM) to probe the redox chemistry and spatial structure of an iron hydroxide thin film adsorbed on an ordered Pt(111) electrode in pH 3 sulfate solution (1 mM H2SO4 + 0.1 M K2SO4) containing 10 mM FeSO4. The Pt(111) electrode was pretreated with the conventional annealing-and-quenching method, which resulted in a sub-monolayer native oxide. After this native oxide was stripped off, the adsorption of Fe2+ ions and the reduction of oxygen concurred to yield an ordered FeOH film on the Pt(111) electrode. In situ STM imaging revealed a unique spoke – wheel (SW) structure between 0.1 and -0.1 V (vs. Ag/AgCl). As opposed to the hexagonal FeO(111) bilayer structure observed on Pt(111) in the vacuum, a distorted hexagonal adlattice was seen with this SW pattern. Shifting the potential positively and negatively resulted in transformations of the SW structure into distorted moiré patterns. The same STM experiment performed with Fe2(SO4)3 led to a disordered film, indicating that ferrous, not ferric, ions were orderly adsorbed on the Pt(111) electrode. The role of anion in the formation of the FeOH film on the Pt(111) electrode was also conducted in pH 3 chloride solution (1 mM HCl + 0.1 M KCl + FeCl2).

A Review of Cobalt-Based Metal Hydroxide Electrode for Applications in Supercapacitors

Supercapacitors are the cutting-edge, high performing, and emerging energy storage devices in the future of energy storage technology. It delivers high energy and produces higher specific capacitances. This research study provides insights into supercapacitor materials and their potential applications by examining different battery technologies compared with supercapacitors’ advantages and disadvantages. Transition metal hydroxides (cobalt hydroxides) have been studied to develop electrodes for supercapacitors and their use in various fields of energy and conversion devices. Cobalt-based metal oxides and hydroxides provide high-capacitance electrodes for supercapacitors. Metal hydroxides combine high electrical conductivity and excellent stability over time. The metal oxides used to prepare the electrodes for supercapacitors are cobalt-based metal oxides and hydroxides. It is stronger than most of the other oxides and has tremendous electrical conductivity. Cobalt hydroxides are also used in supercapacitors instead of other metal hydroxides, such as aluminum hydroxide, copper hydroxide, and nickel hydroxide. This study gives a complete overview of the preparation, synthesis, analysis, and characterization of cobalt hydroxide thin film electrodes by using the electrochemical deposition technique, parameters measurements, important characteristics, material properties, various applications, and future enhancement in supercapacitors.

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.

Self-assembled cobalt hydroxide micro flowers from nanopetals: Structural, fractal analysis and molecular docking study

A 2D structure of cobalt hydroxide was synthesized by the chemical bath deposition method on the glass substrate. The structure of thin-film was studied using X-ray diffraction (XRD) study. UV–vis. spectroscopy, Fourier transforms infrared spectroscopy (FTIR) and Raman spectroscopies were used for structural conformation. The morphological study of thin film has been characterized by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). Cobalt hydroxide thin film is deposited observed in the form of micro-flowers which are self-created by nanosheets like petals structure. The surface growth of thin film was studied with the help of AFM. Fractal analysis was carried based on AFM data. Fractal dimension and surface topographical properties have been calculated from statistical metric. Theoretically and experimentally observed bandgap is well agreed with each other. The possible formation mechanism of flower‐like cobalt hydroxide is discussed based on experimental results. Further molecular docking analysis of cobalt hydroxide with deoxyribonucleic acid (DNA) was predicated. The study shows that interaction between cobalt hydroxide-DNA is observed via the hydroxyl group.

Aqueous solution deposition of indium hydroxide and indium oxide columnar type thin films

Abstract Crystalline In(OH)3 and UV-emitting In2O3 thin films with a unique columnar morphology have been successfully prepared for the first time via a simple aqueous solution deposition method. In the present study, sulfonate-terminated self-assembled monolayers on single-crystal Si wafers were used as substrates for the film deposition. Uniform In(OH)3 thin films formed on self-assembled monolayers in aqueous solutions of InCl3 · 4H2O at 60°C. These films, containing columnar In(OH)3 crystals, showed preferential growth orientation along the [100] direction. The current understanding of the film formation mechanism was discussed. After annealing in air at 400 °C, these films were converted to nanocrystalline In2O3 films without modification of the morphology. Photoluminescence emission from In2O3 films was reported at approximately 3.4 eV, which was ascribed to the near-band-edge emission.

Fabrication of zinc-aluminum layer double hydroxide thin films and their anionic adsorption performance

Layered double hydroxides (LDHs) are also known as hydrotalcite-like compounds or anionic clays. In this work, ZnAl-LDH films were prepared on aluminium (Al) plates by a hydrothermal technique using zinc nitrate solution as the precursors. ZnAl-LDHs films were characterized by SEM, EDX, XRD and FT-IR. The SEM analysis revealed that the ZnAl-LDH films with hierarchical nanoarchitectures on the surface of Al plates. EDX mapping and elemental analysis also showed that Zn, Al, and O dispersed uniformly on the aluminium substrates. XRD results were used to confirm the presence of ZnAl-LDH films as they appeared purely with the typical (003) and (006) peaks of LDH diffraction. The characteristic bands of bending vibrations due to the intercalating water, stretching vibration due to the overlapping signal of carbonate anion and nitrate anion were measured by FT-IR spectroscopy. The brucite structure also exhibited the OH-stretching vibration as well as the ZnO lattice vibration in the spectra. These ZnAl-LDH forms were evaluated for their removal performance against orange II dye solutions.

Development of Multifunctional CoAl Based Layered Double Hydroxide Protective Film on Aluminum Alloy

A protective CoAl-layered double hydroxide (LDH) thin film was developed directly on the aluminum substrate. Further, the low-surface-energy molecules (1H, 1H, 2H, 2H perfluorododecyl trichlorosilane) were incorporated inside the LDH network through an anion exchange mechanism to obtain a superhydrophobic CoAl-LDH surface. The developed films were characterized by scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR), and additional contact angle measurements were made to evaluate the superhydrophobicity of modified CoAl-LDHs against different solutions. The water contact angle (WCA) of the modified CoAl-LDH surface was observed to be about 153° and remained sufficiently stable after long-term immersion in NaCl solution. The effect of excessive ultrasonication on film structural variations and superhydrophobicity was also analyzed for outdoor applications. The high charge transfer resistance observed from the analysis of long-term electrochemical impedance spectroscopy (EIS) indicates the significant corrosion-resistance properties of the developed CoAl-LDHs. This research on protective CoAl-LDHs will bring insights into the understanding of new aspects of surface protection and implementation in many engineering applications.

Colloid self-assembly of c-axis oriented hydroxide thin films to boost the electrocatalytic oxidation reaction

Uniform close-packed superlattice self-assembled from colloidal nanocrystals usually exhibit different chemical and physical properties compared with the homologous bulk materials. Herein, c-oriented NiFe-LDH films (NiFe-LDH-F) and Ni(OH)2 films (Ni(OH)2-F) were successfully fabricated by a colloid self-assembly method. The electrocatalytic oxidation properties of the resulting c-oriented NiFe-LDH-F and Ni(OH)2-F were studied towards the oxygen evolution reaction (OER) and the ethanol electrooxidation reaction (EOR), respectively. Due to orderly stacking c-oriented superlattices, the NiFe-LDH-F and Ni(OH)2-F both showed high proton diffusion coefficients, which significantly improved the electrocatalytic activities. The NiFe-LDH-F on the glassy carbon electrode showed an excellent OER electrocatalytic activity with a small overpotential of 220 mV at 10 mA cm−2 and a low Tafel slope of 53.3 mV dec−1. The Ni(OH)2-F showed a superior EOR performance without obvious passivation. This study may open up a new insight into designing efficient and robust materials for superior electrocatalysis..

Passivating the Surface of Li-Excess Layered Oxide Cathode Materials through Guided Self-Assembly of Metal Hydroxide Thin Films

Passivating the Surface of Li-Excess Layered Oxide Cathode Materials through Guided Self-Assembly of Metal Hydroxide Thin Films

Influence of adsorption small molecules atrazine on nonvolatile resistive switching behavior in Co–Al layered double hydroxide films

Co–Al-layered double hydroxides (LDHs) thin films were prepared by drop-casting process on ITO-coated glass substrates. And then the small molecule atrazine was adsorbed on the Co–Al LDHs film by impregnation method. Current–voltage characteristics revealed nonvolatile resistive switching in Co–Al LDHs adsorbed atrazine films. The Influence of adsorption small molecules atrazine on nonvolatile resistive switching behavior in Co–Al LDHs film has been investigated. By varying the atrazine adsorbed content in Co–Al LDHs thin films, the nonvolatile resistive switching behavior of device could be adjusted in a controlled way. Entirely different nonvolatile resistive switching characteristic, such as write-once read-many-times memory effect and rewritable memory effect are discriminable by the current–voltage curves.

Ce-Doped-MgAl Superhydrophobic Layered Double Hydroxide for Enhanced Corrosion Resistance Properties

Double doped layered double hydroxide thin films were developed directly on the aluminum substrate in two steps: Initially cerium-based MgAl-layered double hydroxide (LDH) were synthesized directly on the anodic aluminum surface via the in situ growth method, and were then modified with the stearate anions through an ion-exchange mechanism to achieve compact multifunctional protective thin films. The structural and morphological characteristics of the developed LDH films were investigated, and the surface contact angle measurements (CA) and self-cleaning properties were analyzed. The obtained double doped LDH film displayed the superhydrophobic characteristic with a water contact angle of ~155°. Furthermore, the superhydrophobic behavior of LDH on exposure to UV radiation (λ = 310 nm) was examined to evaluate outdoor applications. Long-term Electrochemical Impedance Spectroscopy (EIS) analysis was performed to understand the corrosion resistance properties. The introduction of double doped LDHs demonstrates significantly higher corrosion resistance properties than only cerium-modified LDHs and has shown superior stability against 0.1 M NaCl solution.

Efficient Water Splitting Actualized through an Electrochemistry-Induced Hetero-Structured Antiperovskite/(Oxy)Hydroxide Hybrid.

Exploring active, stable, and low-cost bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is crucial for water splitting technology associated with renewable energy storage in the form of hydrogen fuel. Here, a newly designed antiperovskite-based hybrid composed of a conductive InNNi3 core and amorphous InNi(oxy)hydroxide shell is first reported as promising OER/HER bifunctional electrocatalyst. Prepared by a facile electrochemical oxidation strategy, such unique hybrid (denoted as EO-InNNi3 ) exhibits excellent OER and HER activities in alkaline media, benefiting from the inherent high-efficiency HER catalytic nature of InNNi3 antiperovskite and the promoting role of OER-active InNi(oxy)hydroxide thin film, which is confirmed by theoretical simulations and in situ Raman studies. Moreover, an alkaline electrolyzer integrated EO-InNNi3 as both anode and cathode delivers a low voltage of 1.64V at 10mA cm-2 , while maintaining excellent durability. This work demonstrates the application of antiperovskite-based materials in the field of overall water splitting and inspires insights into the development of advanced catalysts for various energy applications.