Black Nickel Research Articles

Enhanced electrocatalytic oxidation of glucose at graphene nanosheets – Metal oxides nanoparticles modified GC electrodes

Herein, graphene nanosheets (GNs) modified glassy carbon electrodes (GCE) with sequentially electrodeposited manganese oxides (MnOx) and nickel oxides nanoparticles (NiOx NPs) were suggested as efficient and durable anodes for glucose oxidation reaction (GOR). The electrocatalytic activity of the various prepared electrodes towards GOR was evaluated by cyclic voltammetry (CV) and chronoamperometry. Furthermore, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), mapping EDX and X-Ray diffraction (XRD) techniques were used to characterize the electrocatalysts. The embedding of these nanostructured metal oxides in the GNs significantly enhanced their activity and stability for GOR. Moreover, the amended GNs with a combination of the two metal oxides (i.e., MnOx and NiOx, where NiOx is the top layer) showed the best electrocatalytic activity and stability for GOR compared to the unmodified GCE or those modified with GNs together with a respective single oxide. These outstanding enhancements are attributed to a synergistic effect between the two metal oxides and GNs matrix, where MnOx is believed to enhance the glucose molecules adsorption and improve the NiOx NPs conductivity via increasing of the content of Ni3+ (NiOOH). Besides, GNs are believed to stabilize and increase the nickel oxyhydroxide (NiOOH) surface concentration. The proposed anode showed high selectivity towards GOR in the presence of several electroactive species with prolonged stability.

Why does NiOOH cocatalyst increase the oxygen evolution activity of α-Fe2O3?

Nickel oxyhydroxide (NiOOH) is known to increase the oxygen evolution reaction (OER) performance of hematite (Fe2O3) photoanodes. In recent experimental studies, it has been reported that the increased OER activity is related to the activation of the hematite (α-Fe2O3) surface by NiOOH rather than the activity of NiOOH itself. In this study, we investigate the reason behind the higher activity and the low overpotentials for NiOOH-Fe2O3 photoanodes using first principles calculations. To study the activity of possible catalytic sites, different geometries with NiOOH as a cluster and as a strip geometry on hematite (110) surfaces are studied. Density functional theory + U calculations are carried out to determine the OER activity at different sites of these structures. The geometry with a continuous strip of NiOOH on hematite is stable and is able to explain the activity. We found that the Ni atoms at the edge sites of the NiOOH cocatalyst are catalytically more active than Ni atoms on the basal plane of the cocatalyst; the calculated overpotentials are as low as 0.39 V.

A low-temperature-annealed and UV-ozone-enhanced combustion derived nickel oxide hole injection layer for flexible quantum dot light-emitting diodes.

Sol-gel derived nickel oxide (NiOx) has been extensively investigated as the hole injection layer (HIL) for many optoelectronic devices because of its advantages of high environmental stability and low cost fabrication. Conventional sol-gel synthesis of NiOx requires high annealing temperature to convert precursors into crystal lattices, which limits its application in flexible devices. To address this issue, a low-temperature (150 °C) combustion method is used to synthesize NiOx. Besides, UV-ozone treatment is further performed to improve the electrical properties of low-temperature-grown NiOx, which leads to the formation of nickel oxyhydroxide (NiO(OH)) surface dipoles and Ni vacancies and thus modifies the energy structure and increases the conductivity of NiOx. Moreover, the formation of surface NiO(OH) induces a vacuum level shift and thus reduces the hole injection barrier. Owing to the enhanced hole injection, solution-processed green QLEDs with optimized UV-ozone treated NiOx HILs exhibit maximum current efficiencies of 45.8 cd A-1 and external quantum efficiencies of 10.9%, which outperform those of the devices with poly(3,4-ethylene dioxythiophene) : poly(4-styrenesulfonate) (PEDOT:PSS) HILs. Meanwhile, these devices also show better long-term stability with a 3.2-fold longer half-life time than that of the PEDOT:PSS-based devices. The demonstrated low-temperature-annealed and UV-ozone enhanced NiOx HILs would enable the realization of flexible QLEDs with high brightness, efficiency and stability.

Experimental Investigation on Properties of Surface Radiation of Solar Collector Receiver Tube Material with Black Nickel Coating

Experimental Investigation on Properties of Surface Radiation of Solar Collector Receiver Tube Material with Black Nickel Coating

Nickel diselenide nanoflakes give superior urea electrocatalytic conversion

Urea electro-oxidation reaction (UOR) is a promising but challenging renewable energy production technology, which generally requires lower electrochemical potential, and shows the capabilities in eliminating a potentially harmful substance from wastewater and/or converting human waste into treasure. However, the state-of-the art UOR suffers from the sluggish kinetics because of the 6 e− transfer process involvement. Herein, as a proof-of-concept study, we synthesized the NiIII -rich nickel diselenide nanoflake through a facile hydrothermal reaction. Compared to the counterpart nickel (oxy) hydroxide, the selenylation processing of nickel successfully produces synergetic effects of more exposed active sites and effective electron transports. Particularly, due to the NiIII –rich nature of the as-synthesized nickel diselenide, the reduction/oxidation reactions between NiII and NiIII is greatly accelerated, which in turn effectively decreases the required overpotentials, prolongate the catalytic lifetime, giving rise to the significantly enhanced UOR performances. In-depth mechanistic analysis evidences that the restructure of nickel diselenide (vs. nickel oxide hydroxide) could be the main reason for affording the decent UOR activity as the oxidation from NiII to NiIII was simultaneous occurred during the selenide species disappear process, a result that may be extended to other selenide -based systems.

A Comparative Study of Nickel, Cobalt, and Iron Oxyhydroxide Anodes for the Electrochemical Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid

2,5-Furandicarboxylic acid (FDCA) has received increasing attention as a near-market platform chemical that can potentially replace terephthalic acid in the production of commercial and high-perfor...

Research of magnetic properties of spolic technosols (alcalic/hyperartefactic) on the landfill of industrial waste from nickel production

Abstract The article presents the results of measurements of magnetic properties of samples spolic technosols (alcalic/hyperartefactic) form the landfill of black nickel mud at Sered’, Slovakia. We measured the dependence of magnetic moment as a function of temperatures (240-340 K) and applied magnetic fields up to 7.2 MA/m (90 kOe). We observed at room temperature the tendency to saturation of magnetic moment. The temperature dependences showed possible ferromagnetic behaviour.

Microstructural analysis and optical properties evaluation of sol-gel heterostructured NiO-TiO2 film used for solar panels

In this study, the production, microstructural characterization and optical properties evaluation of heterostructured NiO-TiO2 films were performed. The film is intended to be used in solar cell applications. Ni-P electroless film was made on an AA7050 aluminum alloy. The film was black nickel electrodeposited by diluted nitric acid and then a thin TiO2 layer coating was deposited by Sol-gel process. The microstructure of the film was analyzed by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS) detector. X-ray diffraction (XRD) technique was used to determine the phases formed in the heterostructured film. Optical properties of the heterostructured film were measured by UV–visible spectroscopy and photoluminescence (PL) Test. Results showed that the heterostructured NiO-TiO2 films had a cauliflower characteristic and was amorphous crystallographically. The heterostructured films also increased the absorption coefficient of the solar absorber plates up to more than 98% in the visible-ultraviolet range. Finally, it was shown that, in the infrared region, the absorption coefficient for dispersion was down to 2%.

Electron‐Beam Induced Water Removal, Phase Change, and Crystallization of Anodic‐Electrodeposited Turbostratic Nickel Hydroxide‐Oxyhydroxide

Water removal, phase transformation, and crystallization of turbostratic nickel hydroxide and oxyhydroxide (Ni(OH)2‐NiOOH) are found to be inducible by the electron beam of a transmission electron microscope (TEM). Under 30 s of beam exposure at an accelerating voltage of 200 keV and a beam current density of 500 mA m−2, the original, characteristic turbostratic structure of Ni(OH)2‐NiOOH is observed to disappear, caused by the quick removal of intercalated water molecules by the electron beam. Increasing the current density from a low value of 1.5 mA m−2 to a high value of 500 mA m−2 can transform the Ni(OH)2‐NiOOH into nickel oxide (NiO) in 1 min. In situ heating and preheating experiments suggest that the transformation is caused by a heating effect induced by the electron beam. The results confirm that the mechanism previously discovered light‐induced actuation of Ni(OH)2‐NiOOH is caused by desorption of water molecules.

Study on emissivity and absorptivity effect of black nickel coated copper used in solar receiver tube material

ABSTRACT Experimental investigation about emissivity (ε) and absorptivity (α) effect of black nickel coated copper used in selective surface of solar receiver tube material with the temperature difference such as 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C and 500°C. The duration of exposure also considered for this study with 10 days gap (10 days, 20 days, 30 days, 40 days and 50 days). These conditions were followed to surface without coating and with coating. The corresponding properties were measured and mentioned experimentally as well theoretically. Transmissibility also considered in the time of study for identify the radiation characteristics.

Research of bi-nickel coatings obtaining process

Modern machine building industry can’t be without the use of special coatings, which allow increasing the physical and mechanical properties of the product. Nickel coatings are widely used, due to wear resistance and corrosion resistance. Black nickel coatings began to be used in solar power engineering, for efficient conversion of solar energy into thermal energy. Also nickel coatings are used in the manufacture of medical instruments. To improve the physical and mechanical properties of nickel coatings, the task was to study the possibility of creating a bi-nickel coating.

Electrochemically Deposited Nickel Oxide from Molecular Complexes for Efficient Water Oxidation Catalysis.

A facile method for the electrodeposition of amorphous nickel oxyhydroxide is described and discussed in which well-defined nickel complexes with pyridinedimethanol ligands are employed as single-source molecular precursors. No buffering agent is required to assist the anodic deposition process. The deposited nickel oxyhydroxide shows high robustness and efficiency for electrocatalytic water oxidation.

Effects of the Aqueous Environment on the Stability and Chemistry of β-NiOOH Surfaces

Nickel oxyhydroxide (NiOOH)-based anodes are among the most promising materials for the electrocatalytic production of oxygen from water under alkaline conditions. We explore the stability of the low-index facets of the catalytically active β-NiOOH phase, namely the (0001), {101N} surfaces, and the as yet unexplored {112N} surfaces, via density functional theory with a Hubbard-U like correction on Ni. We find that their relative stabilities depend strongly on the coordination number of the exposed Ni (cnNi) and O (cnNi). In the vacuum, where passivation of the surface dangling bonds is limited, the stability order is as follows: (0001) > {101N} ≫ {112N}, noting that the coordination numbers for each phase are, respectively, cnNi = 6, 5, and 4, and cnO = 3–4, 2–3, and 2–3. In aqueous media, the order of stability is (0001) > {101N} ≈ {112N}, as the cnNi and cnO of the latter two surface types increase due to water coordination and dissociation. Water adsorption is found to be most favorable on the {1...

Anion insertion enhanced electrodeposition of robust metal hydroxide/oxide electrodes for oxygen evolution

Electrochemical deposition is a facile strategy to prepare functional materials but suffers from limitation in thin films and uncontrollable interface engineering. Here we report a universal electrosynthesis of metal hydroxides/oxides on varied substrates via reduction of oxyacid anions. On graphitic substrates, we find that the insertion of nitrate ion in graphene layers significantly enhances the electrodeposit–support interface, resulting in high mass loading and super hydrophilic/aerophobic properties. For the electrocatalytic oxygen evolution reaction, the nanocrystalline cerium dioxide and amorphous nickel hydroxide co-electrodeposited on graphite exhibits low overpotential (177 mV@10 mA cm−2) and sustains long-term durability (over 300 h) at a large current density of 1000 mA cm−2. In situ Raman and operando X-ray diffraction unravel that the integration of cerium promotes the formation of electrocatalytically active gamma-phase nickel oxyhydroxide with exposed (003) facets. Therefore, combining anion intercalation with cathodic electrodeposition allows building robust electrodes with high electrochemical performance.

Electrosynthesis of azopyrazoles via the oxidation of N-alkylaminopyrazoles on a NiO(OH) anode in aqueous alkali – A green method for N-N homocoupling

A nickel oxyhydroxide [NiO(OH)] anode was exploited to develop a new synthetic route for the electrocatalytic N-N homocoupling of N-alkylaminopyrazoles in an alkaline aqueous medium. The advantages of this green electrochemical methodology include low cost, atom economy and high yields.

In-situ electrochemical formation of nickel oxyhydroxide (NiOOH) on metallic nickel foam electrode for the direct oxidation of ammonia in aqueous solution

A nickel foam-supported Ni(OH)2/NiOOH electrode, synthesized in-situ at a specific electrode overpotential, was used to study the oxidation of ammonia in aqueous solution. Results of voltammetric analysis showed the formal potential of Ni(OH)2/NiOOH transition at +0.6 V (vs. Hg/HgO, pH 11) at which the current profile was improved by electron transfers of NH3 in the electrolyte. Selectivity of NH3 conversion to NO3− and N2 was evaluated by batch constant current experiments. Electrochemical parameters, including solution pH (6–12), temperature (20–40 °C), current density (0.2–3 mA cm−2), and initial NH3-N concentration (20–450 mg-L−1), that may affect ammonia oxidation toward nitrogen selectivity were studied. At constant current density of 1.5 mA cm−2A, ammonia removal reached 98.5% and NO3− was the major product at initial NH3-N concentration of 50 mg-L−1 in 7 h. By contrast, N2 evolution dominated at low current density (<1 mA cm−2) and high initial NH3-N concentration (i.e., >100 mg-L−1). A surface steady-state approach, with NH3 deprotonation as the rate-limiting step, provided the reaction pathways of NH3 conversion to molecular nitrogen byproduct.

Electrochemically Produced Zinc Oxide Electrode in Rechargeable Alkaline Batteries

The zinc electrode is a commonly used negative electrode in a host of commercially important battery systems such as Zinc-Manganese dioxide (Zn-MnO2) and Silver-Zinc (Ag2O-Zn) batteries. Out of these the Zn-MnO2 battery is a commercially successful non-rechargeable battery because of its inherent safety, low cost and relatively high energy density. Recent experimental work has shown that a rechargeable Zn-MnO2 battery is capable of giving 3000 cycles when cycled at 10% of the MnO2 theoretical 1 e- capacity and 1.5% of the Zn 2 e- capacity. However, at higher zinc utilization the battery is short-lived. Dendrite shorting, shape change and MnO2 poisoning are some of the main mechanisms of zinc electrode failure. These failure mechanisms are closely related to the high electrochemical solubility and the unrestrained movement of zincate ions, formed at the anode on discharge. Therefore, it is imperative to immobilize zincate ion either via complexation or intercalation. Hydrotalcite-like layered materials are recently reported as anode active materials for Nickel -Zinc batteries and have been suggested to capture zinc ions into their structure. We report the cycling performance of Zinc Aluminum Bismuth hydrotalcite for 900 cycles at 10% zinc utilization in 6 M potassium hydroxide solution saturated with zinc oxide against Nickel oxyhydroxide cathode. X-ray diffraction results show the presence of zinc oxide on discharge and do not support the presence of a layered hydrotalcite after cycling, as has been reported in literature. This is attributed to the instability of the hydrotalcite crystal structure in concentrated alkaline electrolytes. The results of this study show improved performance because of zinc oxide saturated electrolyte. To inherently reduce the tendency of the zinc electrode for dendrite shorting and shape change we investigate a fundamental question of the difference between the cycling of a zinc electrode versus the cycling of an electrochemically formed zinc oxide electrode. A novel, first of its kind, battery cycling protocol is reported where manganese dioxide cathode is cycled against a zinc oxide anode formed in-situ. This is made possible by first deeply discharging the manganese dioxide against a metallic zinc electrode resulting in complete conversion of metallic zinc to zinc oxide. Subsequent cycling of the electrochemically formed zinc oxide anode and cathode is carried out at a shallow depth of discharge. Adopting this strategy has resulted in improved cycle life at 12% utilization of the zinc electrode. We dissect the cells at different cycles to see an evolution of the active material in the cell with metallic zinc and the cell with electrochemically formed zinc oxide. Bulk electrolyte analysis for zincate ion shows that the zinc oxide cell is under-saturated while the control cell is saturated with zincate ions. Preliminary analysis results show that cycling of electrochemically produced zinc oxide rather than metallic zinc anode reduces shape change and dendrites because of reduction of zincate ions in the bulk electrolyte.

Water Oxidation Catalysis for NiOOH by a Metropolis Monte Carlo Algorithm.

Understanding catalytic mechanisms is important for discovering better catalysts, particularly for water splitting reactions that are of great interest to the renewable energy field. One of the best performing catalysts for water oxidation is nickel oxyhydroxide (NiOOH). However, only one mechanism has been adopted so far for modeling catalysis of the active plane: β-NiOOH(01̅5). In order to understand how a second reaction mechanism affects catalysis, we perform Density Functional Theory + U (DFT+U) calculations of a second mechanism for water oxidation reaction of NiOOH. Then, we use a Metropolis Monte Carlo algorithm to calculate how many catalytic cycles are completed when two reaction mechanisms are competing. We find that within the Metropolis algorithm, the second mechanism has a higher overpotential and is therefore not active even for large applied biases.

Flexible metasurface black nickel with stepped nanopillars.

We report on a monolithic, all-metallic, and flexible metasurface perfect absorber [black nickel (Ni)] based on coupled Mie resonances originated from vertically stepped Ni nanopillars homoepitaxially grown on an Ni substrate. Coupled Mie resonances are generated from Ni nanopillars with different sizes such that Mie resonances of the stepped two sets of Ni nanopillars occur complementarily at different wavelengths to realize polarization-independent broadband absorption over the entire visible wavelength band (400-760nm) within an ultra-thin surface layer of only 162nm thick in total. Two-step double-beam interference lithography and electroplating are utilized to fabricate the proposed monolithic metasurface that can be arbitrarily bent and pressed. A black nickel metasurface is experimentally demonstrated in which an average polarization-independent absorption of 0.972 (0.961, experiment) in the entire visible band is achieved and remains 0.838 (0.815, experiment) when the incident angle increases to 70°.

On the use of photothermal techniques for the characterization of solar-selective coatings

The efficiency of the conversion of solar energy into thermal energy is determined by the optical and thermal properties of the selective coating, in particular, the solar absorptance and thermal emittance at the desired temperature of the specific application. Photothermal techniques are the most appropriate methods to explore these properties, however, a quantitative determination using photothermal radiometry, which is based on the measurement of emitted radiation caused by the heating generated by a modulated light source, has proven to be elusive. In this work, we present experimental results for selective coatings based on electrodeposited black nickel–nickel on both stainless steel and copper substrates, as well as for commercial TiNOX coatings on aluminum, illustrating that the radiation emitted by the surface depends on the optical absorption, thermal emissivity and on the light-into-heat energy conversion efficiency (quantum efficiency). We show that a combination of photothermal radiometry and photoacoustic spectroscopy can successfully account for these parameters, and provide values for the emissivity in agreement with values obtained by Fourier-transform infrared spectroscopy.