Nickel Nitrate Solution Research Articles

Preparation of Hydrogen Electrodes of Solid Oxide Cells by Infiltration: Effects of the Preparation Procedure on the Resulting Microstructure.

In this work, the infiltration technique was used to produce hydrogen electrodes for solid oxide cells. Different infiltration methodologies were tested in order to try to shorten the infiltration cycle time. The porous scaffolds used for infiltration were based on highly porous yttria-stabilized zirconia (YSZ) obtained by etching the reduced nickel from the Ni-YSZ cermet in HNO3 acid. The support had a complex structure which included a ~130 µm porous functional layer with small pores and a ~320 µm thick supporting layer with large pores. Infiltrations have been carried out using aqueous nickel nitrate solutions. Various infiltration procedures were used, differing in temperature/time profiles. The results show that slow evaporation is crucial for obtaining a homogeneous material distribution leading to high-quality samples. A longer evaporation time promotes the proper distribution of nickel throughout the porous scaffold. The shortening of the heat treatment procedure leads to blockage of the pores and not-uniform nickel distribution.

Mixed oxides CuO-NiO fabricated for selective detection of 2-Aminophenol by electrochemical approach

New heterometallic complex [NiCu(NO3)2(H2O)2] (1) was prepared via the reaction of aqueous solutions of (oxalic acid, nickel nitrate and copper nitrate). Mixed oxide CuO-NiO was successfully obtained with different morphological structures (2) and (3) through the annealing of 1 at different temperature 300°C and 600°C, respectively. The materials were characterized using FT-IR, TGA, XRD and SEM. As showed from XRD data, with increasing the calcination temperature the crystallinity of CuO-NiO in sample 3 was improved and the diffraction peaks exhibited narrower and stronger than CuO-NiO in sample 2. The average size of CuO-NiO crystals obtained was calculated from Debye-Scherrer equation and found to be 16.65nm. To assemble the working electrode of 2-aminophenol (2-AP) chemical sensor, a thin layer of CuO-NiO NPs was deposited on glassy carbon electrode (GCE) with conducting binder and used to detect 2-AP in aqueous medium successfully. The chemical sensor is exhibited the higher stability, good sensitivity (20.2729μAmM−1cm−2) and enhanced electrochemical activity at room conditions. Therefore, the fabricated chemical sensor with active CuO-NiO NPs may be an effective and sensitive sensor for detection of hazardous materials by reliable I–V method for broad scales environmental safety of and healthcare sectors.

Optimization of low value electrodeposition parameters of nano-structured NiO electrochromic thin films

In this work, the electrochromic and structural properties of NiO thin films prepared using optimized low value electrodeposition parameters were studied. The optimized parameters were deposition current density, molar concentration of nickel nitrate solution, and deposited charge density. The highest electrochromic characteristics corresponded to deposition parameters of −0.05 mA/cm2 deposition current density, 0.02 M of Ni(NO3)2.6H2O solution, and charge density of 80 mC/cm2. For this optimized film, at 630 nm wavelength, the transmittance modulation ΔT was 76%, the efficiency η was 19 cm2/C, the charge reversibility Qc/Qa was 97%, and a remarkable contrast ratio CR of 5.9. In addition, a good cycling stability was confirmed up to 900 cycles. Optimized NiO thin films were poorly crystallized exhibiting a nano-flake structure, high porosity, and homogeneity.

Synthesis and properties of the materials in Ni/SrTi1-xCrxO3 system

Synthesis of materials in Ni/SrTi1-xCrxO3 system was undertaken towards evaluation of the possibility of their application in SOFC technology. Materials with different chromium and nickel content were obtained. Single-phase SrTi1-xCrxO3 (x = 1, 4 and 6 mol. %) samples synthesized by modified citrated method were impregnated with nickel nitrate solution to achieve different Ni concentration (1, 5, 10 or 20 wt %). The proper thermal treatment resulted with formation of composites in NiO/doped-SrTiO3 system. The obtained materials were investigated for their structural, redox and electrical properties. X-ray diffraction analysis showed the presence of strontium titanate and nickel oxide in composite systems but for materials with the highest amount of chromium a small amount of strontium chromate was also detected. The redox abilities of NiO/SrTi1-xCrxO3 systems examined by TPR/TPOx measurements indicate that all materials have catalytic potential in reduction-oxidation reaction. Moreover these tests showed that nickel can be incorporated into the strontium titanate structure during TPOx cycles. The results of electrical properties measurements carried out in synthetic air and H2/Ar atmosphere indicate that nickel introduced into the materials does not affect the conductivity nor conduction mechanism. Thermal expansion coefficients for obtained composites are practically independent of the amount of chromium incorporated into the SrTiO3 structure but slightly change with amount of nickel introduced to the system.

Synthesis of Ni base nanoparticles by W/O emulsion combustion

To develop a process of fine particle production by spray pyrolysis, spray combustion of W/O (water-in-oil) emulsion, of which water phase was raw material solution and oil phase was fuel for heat source of high-temperature reaction field, was investigated. In this study, nickel oxide particles, which were a preliminary step of the nickel fine particle production, were synthesized and its structural characteristics were evaluated. Mixed solution of nickel nitrate and white kerosene was used as raw material. W/O emulsions were prepared using ultrasonic homogenizer and stirring these raw materials adding a surfactant. These emulsions were burning in a high temperature furnace to produce nickel oxide particles. The mean particle diameter of produced particles was less than 20 nm according to TEM observation. The diameter of the particles was much smaller than the estimated value based on the size distribution of dispersed solution phase in the emulsions and its concentration. Moreover, there is no effect of the concentration of the aqueous solution phase. On the other hand, X-ray diffraction pattern showed that the produced particles were complex of metal nickel with nickel oxide.Graphic abstract

Activated carbon surface modification by catalytic chemical vapor deposition of natural gas for enhancing adsorption of greenhouse gases

Activated Carbon (AC) was modified by Catalytic Chemical Vapor Deposition (CCVD) of Urban Natural Gas (UNG) using microwave irradiation. Pretreatment of the as-prepared activated carbon was performed by washing with nitric acid and Ni impregnation by nickel nitrate solution (with 1.5–3.5 wt.% Ni/AC) followed by N2 thermal treatment at 450 °C. Modification of the AC surface was carried out by carbon source flow through the surface under microwave irradiation. Carbon nanofibers (CNFs) growth was observed on the surface of AC by FESEM analysis. The properties of the surface were characterized by FTIR, FESEM, EDX and BET analysis. The effect of the carbon source and the content of Ni/AC were investigated on the CNF quality. Among three carbon sources (pure methane, methane-ethane mixture, and UNG), the fibers formed under UNG flow possessed the best surface characteristics. Presence of Ni improved the rate of nanofiber formation at lower temperatures and shortened the run time. It was observed that specific surface area and total pore volume of the modified AC increased by 12% and 41% after CNF growth, respectively. Pore volume distribution indicated a slight reduction of the micropores while the number of mesopores increased with fiber formation. Equilibrium adsorption experiments were conducted on the samples for CO2, CH4, CO, and H2. The adsorption capacity and selectivity of the greenhouse gases have been improved up to 15% and 60%, respectively, whereas hydrogen adsorption capacity was negligible and remained unchanged after surface modification.

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

Photocatalytic degradation of alizarin red dye in aqueous solution using titania-nickel and titania-cobalt nanocomposites

Titanium dioxide (TiO 2 ) was prepared by Sol-gel method which involved hydrolysis of Titanium trichloride (TiCl 3 ) with concentrated hydrochloric acid and oxidation by hydrogen peroxide. Doping of the TiO 2 was effected at 10% Ni-TiO 2 and 10% Co-TiO 2 using aqueous solutions of nickel nitrate and cobalt nitrate respectively. Characterization by X-ray Diffraction Crystallography (XRD) and Scanning Electron Microscopy (SEM) showed that the surface area and crystallinity of TiO 2 increased through doping. The XRD and SEM data confirmed the observed increase in the photocatalytic activities of the doped versus the undoped TiO 2 photocatalysts. Photocatalytic activities of both the doped and undoped TiO 2 was investigated on the photodegradation of Alizarin red dye. With a constant dye concentration of 25 ppm and temperature of 40 o C, it was observed that for all varying concentrations except 0.25 g/l of catalyst at 240 mins, the percentage degradation was of the order TiO 2 < Co-TiO 2 < Ni-TiO 2 . At the 0.25 g/l concentration of catalyst at 240 mins, the photocatalytic activities of the Ni-TiO 2 and Co-TiO 2 were observed respectively to be about 9 times and 12 times that of the TiO 2 . Keywords: Titanium dioxide, titania-nickel, titania-cobalt,alizarin red and photocatalysts

Effect of the SiO2 support morphology on the hydrodesulfurization performance of NiMo catalysts

Abstract

Investigation of Preparation, Solubility and Stability Properties of Nickel Hydrazine Nitrate (NiHN)

AbstractFollowing an initial, brief, review of the environmental problems associated with the use of lead based primers, and also some of their potential replacements, this study investigated the preparation of the promising, lead free, energetic material nickel hydrazine nitrate by different methods. All three methods trialed produced the same, analytically indistinguishable, compound but with minor changes in visual appearance. The solution properties governing the precipitation process were investigated in a controlled pH titration experiment. Product solubility in a number of common solvents was investigated. Aqueous ammonia and hydrazine hydrate proved the best “non‐destructive solvents” for the solid. UV spectroscopy and conductivity of the solutions obtained was used as an indicator of the processes involved in the solubility. Using the critical pH conditions for precipitation from aqueous solutions of hydrazine and nickel nitrate the formation constant for the tris hydrazine complex was determined. Also using the solubility of the tris‐hydrazine complex in concentrated hydrazine hydrate an equilibrium constant for the formation of the soluble hexa‐hydrazine complex from insoluble tris hydrazine complex was determined. These values were compared with similar values for nickel hydrazine complexes with other anions. The origins of these differences were discussed. Further work on controlling and measuring the particle size of the NiHN produced should be considered.

Hydrogenation of nitrobenzene over a composite catalyst based on zeolite supported N-doped carbon nanotubes decorated with palladium

A catalyst nanocomposite was synthesized based on zeolite supported nitrogen-doped carbon nanotubes (N-CNT) decorated with palladium nanoparticles. Zeolite beads impregnated with nickel nitrate solution were used as CCVD catalyst support during the synthesis of N-CNT. Then the zeolite supported N-CNT was decorated with palladium nanoparticles and the final nanocomposite was tested in nitrobenzene hydrogenation. The structure of the nanocomposite was characterized by SEM. The surface of the zeolite beads is extensively covered by N-CNT. The particle size distribution of the palladium nanoparticles on the surface of N-CNT is relatively homogenous (< 7 nm). The catalytic activity of the nanocomposite was the highest at 10 bar and 323 K while the achieved nitrobenzene/aniline conversion was 99.9% after 4 h of hydrogenation.

Preparation of Ni-based egg-shell-type catalyst on cylinder-shaped alumina pellets and its application for hydrogen production via steam methane reforming

Nickel-based ‘egg-shell-type’ catalysts were prepared using cylinder-shaped alumina pellets as supports. In the egg-shell-type catalysts, nickel was selectively located in the outer region of the alumina pellets. Ethylene glycol or 1-octanol were used as hydrophobic solvents to retard internal penetration of the alumina pellets by the nickel nitrate solution. Without hydrophobic solvent, a ‘homo-type’ catalyst with even nickel distribution inside the alumina pellets was achieved. Cross-sectional images and SEM-EDS analysis of the cylinder-shaped alumina pellets showed that nickel concentration in the egg-shell-type catalyst was higher in the outer region and decreased towards the inner region of the alumina pellets. The egg-shell-type nickel distribution was maintained after subsequent magnesium impregnation and calcination processes. X-ray diffraction patterns and temperature programmed reduction profiles showed that the only difference between homo-type and egg-shell type catalysts, when their nickel loading was the same, was the nickel distribution inside pellets; and this was shown to cause significant difference in their catalytic activity in the steam methane reforming (SMR) reaction. For the homo-type catalyst, nickel loading of 3.5 wt% was insufficient for the SMR reaction, as metallic nickel particles were evenly distributed through the entire alumina pellet. However, nickel loading of 3.5 wt% was sufficient for the egg-shell-type catalyst, because active sites with metallic nickel particles were concentrated in the outer region of the pellets. These experimental results confirmed that the egg-shell-type nickel distribution is a favorable design for an SMR reaction catalyst.

Synthesis, Characterization and Using of Nano - Nickel Metal Loaded on Egyption Kaolin for Reduction of p-Nitrophenol to p-Aminophenol

The p-aminophenol was prepared by reduction of p-nitrophenol over nano-sized nickel catalysts without support and with Egyptian kaolin as support. Hydrazine hydrate was used as hydrogen source in this reaction. Using solutions of nickel nitrate of appropriate concentrations to obtain catalysts with concentrations 2.5, 5 and 10% nickel loaded on Egyptian kaolin. The prepared Ni catalysts were characterised using X-ray and SEM before and after reduction of p-nitrophenol. The results showed that the degree of crystallinity of nano nickel particles was decreased after the reduction with agglomeration of nano nickel particles. The reduction of p-nitrophenol was performed with different Ni-concentrations from 2.5-10%. The results showed that the increase of Ni-content led to a decrease of the time taken for complete reduction of p-nitrophenol and showed that Ni supported on kaolin was more active than the unsupported Ni catalyst for reduction of p-nitrophenol to p- aminophenol.

Synthesis of nano - nickel metal loaded on Faujasite-Zeolite for reduction of p-nitro phenol to p-amino phenol

Abstract Nickel nanoparticles and Ni supported on faujasite- zeolite were prepared by using a solution of nickel nitrate of appropriate concentrations. The catalysts with 2.5, 5 and 10% nickel were reduced with hydrazine hydrate in the presence of alkali and used in reduction of p-nitrophenol to p- aminophenol. The prepared Ni catalysts were characterised by X-ray and SEM before and after conducting the reduction of p-nitrophenol.The results showed that catalysts contains nano nickel were durable in reduction of p-nitro phenol to p- amino phenol. The Ni supported on faujasite-zeolite was more active than the unsupported Ni catalyst.

Hydrogenation Reprocessing of Tire Rubber in a Mixture with Petroleum Tar in the Presence of Ultradispersed Catalysts

Hydroconversion of tire rubber in a mixture with petroleum tar in the presence of ultradispersed catalysts formed in situ in a hydrocarbon medium from the catalyst precursor was studied. Aqueous solutions of ammonium paramolybdate, nickel nitrate, and cobalt nitrate and mixtures of these solutions were used as catalyst precursors. In hydroconversion of a mixture of rubber and tar, the ultradispersed catalysts used increase the yield of distillate products and reduce the yield of the gas and condensation products. The yield of the liquid products is maximal (64.0%) with the Mo catalyst and decreases in the order Mo, Ni, Co. Binary ultradispersed catalysts based on molybdenum and nickel compounds show high performance.

Surface Composition and Structure of Highly Porous Materials Based Zirconia Stabilized with Yttria

Highly porous permeable materials have been fabricated from zirconia nanopowders stabilized with 2, 3, and 7 mol % yttria by duplicating the polymer matrix. It is shown that the samples are characterized by a complex surface relief formed by sintered powder agglomerates resulted from the agglomeration treatment. It is established by Raman spectroscopy that the phase composition of the material surface is identical to the composition of initial nanopowders and is presented only by the tetragonal modification in all studied cases. It is shown that the deposition of nickel (an active catalytic component) from nickel nitrate solutions or the deposition of metallic nickel on surfaces of ZrO2 stabilized with 3 mol % Y2O3 causes the formation of a monoclinic modification. Only a tetragonal modification is identified on the surface of highly porous ZrO2 samples stabilized with 2 and 7 mol % Y2O3. When using the peak splitting procedure, the shift of the integral peak intensity toward lines characteristic of the monoclinic modification is fixed.

Freestanding two-dimensional Ni(OH)2 thin sheets assembled by 3D nanoflake array as basic building units for supercapacitor electrode materials

Freestanding two dimensional (2D) porous nanostructures have great potential in electrical energy storage. In the present work, we reported the first synthesis of two-dimensional (2D) β-Ni(OH)2 thin sheets (CQU-Chen-Ni-O-H-1) assembled by 3D nanoflake array as basic building units under acid condition by direct hydrothermal decomposition of the mixed solution of nickel nitrate (Ni(NO3)2) and acetic acid (CH3COOH, AA). The unique 3D nanoflake array assembled mesoporous 2D structures endow the thin sheets with a high specific capacitance of 1.78Fcm−2 (1747.5Fg−1) at the current density of 1.02mAcm−2 and good rate capability of 67.4% retain from 1.02 to 10.2mAcm−2. The corresponding assembled asymmetric supercapacitor (ASC) achieves (CQU-Chen-Ni-O-H-1//active carbon (AC)) a high voltage of 1.8V and an energy density of 23.45Whkg−1 with a maximum power density of 9kWkg−1, as well as cycability with 93.6% capacitance retention after 10,000 cycles. These results show the mesoporous thin sheets have great potential for SCs and other energy storage devices.

Effect of the preparation method on the hydrogenation activity of Ni/SBA-15 catalysts: Comparison of EDTA complexation and DPU

The SBA-15 material was synthesized and used as a support for nickel catalysts with 4 and 10wt.% metal loadings. Three preparation methods were used: a conventional incipient wetness impregnation with a nickel(II) nitrate solution (IM method), impregnation with a [Ni(EDTA)]2− complex solution (ED method) and deposition-precipitation with urea (DP method). The support and catalysts were characterized by N2 physisorption, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy and temperature-programmed reduction. The reduced nickel catalysts were also characterized by high resolution transmission electron microscopy and powder XRD. Catalysts were evaluated in the hydrogenation of naphthalene in order to compare their catalytic performance (activity and selectivity). The obtained results show that the preparation method affected the dispersion and size distribution of nickel nanoparticles deposited on the SBA-15 surface as well as the degree of their reduction. ED and DP methods led to a better dispersion of Ni and higher hydrogenation activity in comparison with the conventional IM procedure. In addition, the catalysts’ selectivity to decalins and their ability to isomerize cis-decalin to trans-decalin were also affected by the preparation method used, increasing in the following order: XNS-IM < XNS-DP < XNS-ED for both Ni loadings (4 and 10wt.%). Therefore, the importance of the method used for the preparation of the Ni/SBA-15 catalysts was demonstrated.

Electrochromism of Ni(OH)2 films obtained by cathode template method with addition of Al, Zn, Co ions

The films from mixed solutions of nickel-aluminum, nickel-zinc and nickel-cobalt have been prepared using the cathodic template synthesis with polyvinyl alcohol as a template. The prepared films have been studied by means of X-ray diffraction analysis, cyclic voltamperometry with simultaneous recording of the transparency change. The results have shown that the addition of aluminum and cobalt allows obtaining layered double hydroxides. However, the addition of aluminum leads not only to the formation of layered double hydroxide but also to poisoning of the active material. In case of deposition from solutions containing cobalt, the obtained films have good electrochemical and electrochromic properties, and also two-stage color transition. The film obtained at a molar ratio of nickel to cobalt of 8:1 possesses the best electrochromic characteristics and coloration degree of 0.8, which is more than for the film obtained from nickel nitrate solution without additives of other metals by 0.2.

Production of High-Purity Anhydrous Nickel(II) Perrhenate for Tungsten-Based Sintered Heavy Alloys.

This paper presents a method for the production of high-purity anhydrous nickel(II) perrhenate. The method comprises sorption of nickel(II) ions from aqueous nickel(II) nitrate solutions, using strongly acidic C160 cation exchange resin, and subsequent elution of sorbed nickel(II) ions using concentrated perrhenic acid solutions. After the neutralization of the resulting rhenium-nickel solutions, hydrated nickel(II) perrhenate is then separated and then dried at 160 °C to obtain the anhydrous form. The resulting compound is reduced in an atmosphere of dissociated ammonia in order to produce a Re-Ni alloy powder. This study provides information on the selected properties of the resulting Re-Ni powder. This powder was used as a starting material for the production of 77W-20Re-3Ni heavy alloys. Microstructure examination results and selected properties of the produced sintered heavy alloys were compared to sintered alloys produced using elemental W, Re, and Ni powders. This study showed that the application of anhydrous nickel(II) perrhenate in the production of 77W-20Re-3Ni results in better properties of the sintered alloys compared to those made from elemental powders.