Artículos de revistas: "Mixed nickel-cobalt hydroxide precipitation"

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Harvey, Robin, Robert Hannah y James Vaughan. "Selective precipitation of mixed nickel–cobalt hydroxide". Hydrometallurgy 105, n.º 3-4 (enero de 2011): 222–28. http://dx.doi.org/10.1016/j.hydromet.2010.10.003.

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Ichlas, Z. T., M. Z. Mubarok, A. Magnalita, J. Vaughan y A. T. Sugiarto. "Processing mixed nickel‑cobalt hydroxide precipitate by sulfuric acid leaching followed by selective oxidative precipitation of cobalt and manganese". Hydrometallurgy 191 (enero de 2020): 105185. http://dx.doi.org/10.1016/j.hydromet.2019.105185.

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Wang, Yue Hua, Li Wen Ma, Yun He Zhang, Zhao Jie Huang y Xiao Li Xi. "Preparation of Regenerated Cathode Material Lithium Nickel Cobalt Oxide LiNi_0.7Co_0.3O₂ Form Spent Lithium-Ion Battery". Materials Science Forum 944 (enero de 2019): 1179–86. http://dx.doi.org/10.4028/www.scientific.net/msf.944.1179.

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With the development of new energy vehicles, urgent issues have attracted considerable attention. Some power batteries have entered the scrapping period, with the imperative recycling of used power batteries. Some studies have predicted that by 2020, the amount of power lithium battery scrap will reach 32.2 GWh, corresponding to ~500,000 tons, and by 2023, the scrap will reach 101 GWh, corresponding to ~1.16 million tons. In this study, nickel-cobalt-lithium LiNi0.7Co0.3O2cathode materials are regenerated from spent lithium-ion battery cathode materials as the raw material, which not only aids in the reduction of pressure on the environment but also leads to the recycling of resources. First, extraction is employed using extracting agent p204 to remove aluminum ions from an acid leaching solution. Extraction conditions for aluminum ions are: include a phase ratio of 1:2,a pH of 3, an extractant concentration of 30%, and a saponification rate of 70%.Next, the precursor was prepared by co-precipitation using sodium hydroxide and ammonia water as the precipitant and complexion agents, respectively; hence, the cathode material can be uniformly mixed at the atomic level. The precursor and lithium hydroxide were subjected to calcination at high temperature using a high-temperature solid-phase method. The Calcination conditions include an air atmosphere ; a calcination temperature of 800° °C ; a calcination time of 15 h, an n (precursor): n (lithium hydroxide) ratio of 1:1.1.The Thermogravimetric analysis revealed that the synthesis temperature should not exceed 850°C. X-ray diffraction analysis, scanning electron microscopy, and energy spectrum analysis of the cathode material revealed a composition comprising Li, Ni, and Co oxides. After analysis, the material obtained is lithium nickel-cobalt-oxide, LiNi0.7Co0.3O2, which is a positive electrode material with good crystallinity and a regular layered structure.

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Muzayanha, Soraya Ulfa, Cornelius Satria Yudha, Adrian Nur, Hendri Widiyandari, Hery Haerudin, Hanida Nilasary, Ferry Fathoni y Agus Purwanto. "A Fast Metals Recovery Method for the Synthesis of Lithium Nickel Cobalt Aluminum Oxide Material from Cathode Waste". Metals 9, n.º 5 (27 de mayo de 2019): 615. http://dx.doi.org/10.3390/met9050615.

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An approach for a fast recycling process for Lithium Nickel Cobalt Aluminum Oxide (NCA) cathode scrap material without the presence of a reducing agent was proposed. The combination of metal leaching using strong acids (HCl, H2SO4, HNO3) and mixed metal hydroxide co-precipitation followed by heat treatment was investigated to resynthesize NCA. The most efficient leaching with a high solid loading rate (100 g/L) was obtained using HCl, resulting in Ni, Co, and Al leaching efficiencies of 99.8%, 95.6%, and 99.5%, respectively. The recycled NCA (RNCA) was successfully synthesized and in good agreement with JCPDS Card #87-1562. The highly crystalline RNCA presents the highest specific discharge capacity of a full cell (RNCA vs. Graphite) of 124.2 mAh/g with capacity retention of 96% after 40 cycles. This result is comparable with commercial NCA. Overall, this approach is faster than that in the previous study, resulting in more efficient and facile treatment of the recycling process for NCA waste and providing 35 times faster processing.

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Javidan, Abdollah, Mir Hassan Hosseini y S. L. Shaifi. "Preparation of Co_0.5Zn_0.5Fe₂O₄ and Co_0.5Mn_0.5Fe₂O₄ Nanoferrites by Co-Precipitation Method". Advanced Materials Research 620 (diciembre de 2012): 7–11. http://dx.doi.org/10.4028/www.scientific.net/amr.620.7.

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Nanoparticles of Cobalt-zinc ferrite (Co0.5Zn0.5Fe2O4) and Cobalt-manganese ferrite (Co0.5Mn0.5Fe2O4) have been synthesized at room temperature by co-precipitation method with and without calcination process. Starting materials for preparation of nanooxides were Co (NO3)2.6H2O, ZnCl2, Fe (NO3)3.9H2O and Mn (NO3)2.4H2O. These salats were mixed in stoichiometric amounts and precipitated with sodium hydroxide. Synthesised materials are confirmed by XRD and SEM analysis. The FTIR spectra of nanooxides have been analyzed in the frequency range of 400-4000cm-1.

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Zhang, Pei Xin, Mu Chong Lin, Qiu Hua Yuan, Zhen Zhen Fan, Xiang Zhong Ren y Dong Yun Zhang. "Co-Precipitation Synthesis and Optimization Process for LiCo_1/3Ni_1/3Mn_1/3O₂". Advanced Materials Research 92 (enero de 2010): 55–64. http://dx.doi.org/10.4028/www.scientific.net/amr.92.55.

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With the acetates of nickel, manganese and cobalt as raw materials and lithium hydroxide as precipitation agent, the precursor Ni1 / 3 Co1 / 3 Mn1 / 3 (OH) 2 was first prepared by chemical coprecipitation method, which was then mixed and ballmilled with certain stoichiometric ratios of LiOH∙H2O, and ultimately obtained LiCo1/3Mn1/3Ni1/3O2 after calcination process. Single-factor experiment method, in conjunction with XRD, SEM, and charge-discharge test, was utilized to study the influence of various factors, including the dispersion way of precursor, pH value of reaction solution, and the content of ballmilling lithium on the electrochemical properties of LiCo1/3Mn1/3Ni1/3O2. The results indicated that: (1) the material dispersed by ultrasonic treatment revealed excellent cycling performance, its ratio of capacity fading decreased at least 34.1% compared to those without ultrasonic process; (2) the optimum conditions of fabricating LiCo1/3Mn1/3Ni1/3O2 may be summarized as the treatment of ultrasonic dispersion, suitable pH value (12~13) and stoichiometric ratio (1.0) of ballmilling lithium.

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Nor, S. Hanim Md, M. Nazri Abu Shah, Abdul Hadi y Kamariah Noor Ismail. "Effect of Co Doping on the Properties of Ce0.75Zr0.25O2 Nanocatalyst". Applied Mechanics and Materials 575 (junio de 2014): 93–96. http://dx.doi.org/10.4028/www.scientific.net/amm.575.93.

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5wt% Co deposited on a support catalyst Ce0.75Zr0.25O2 mixed oxide were prepared by combination of microemulsion and deposition-precipitation method followed by calcinations at temperature 500°C. The microemulsion component comprise of cetyl trimetyl ammonium-bromide (CTAB), 1-butanol, n-octane and aqueous solution. Sodium hydroxide (NaOH) was used as precipitation precursor for the preparation of water-in-oil microemulsions method. The particles were characterized by X-ray diffraction (XRD), N2 adsorption-desorption analysis and Field Emission Scanning Electron Microscopy (FESEM). The results showed the preparation method has significant influences on the textural and structure properties of Co/Ce0.75Zr0.25O2. The formation of Co/Ce0.75Zr0.25O2 inhibit the better performance based on the particles size, specific surface area and particle distribution of cobalt into Ce0.75Zr0.25O2.

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Li, Zhi Wei, Xu Xiang y Zong Min Tian. "Low-Temperature Liquid-Phase Synthesis and Electrochemical Activity of α-Nickel Hydroxide with Flower-Like Micro-/Nano-Structure". Advanced Materials Research 347-353 (octubre de 2011): 3379–83. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3379.

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The synthesis of α-nickel hydroxide has been achieved via a facile liquid-phase precipitation approach, using the mixed solvents of ethylene glycol and water as reaction medium at low temperature. The XRD characterization indicates that pure phase α-Ni(OH)2can be obtained under variable temperature and pH value. The products present a flower-like micro-/nano-structure assembled with curved nanosheets. The nanosheets have the width of 100~500 nm and the thickness of 20~70 nm. The cavities are formed in the structure due to the interconnection of curved nanosheets. The solvents play a key role in the formation of Ni(OH)2with different forms. Pure phase α-Ni(OH)2can only be synthesized in the mixed solvents of ethylene glycol and water. Cyclic voltammetry was applied to test the electrochemical activity of the as-synthesized α-Ni(OH)2. The findings suggest that the α-Ni(OH)2with a micro-/nano-structure exhibits excellent electrochemical activity, which may be considered as a promising candidate of electrode material.

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Pohorenko, Yuliia, Anatoliy Omel’chuk, Olexandr Ivanenko y Tamara Pavlenko. "SYNTHESIS OF COMPLEX OXIDE COMPOSITIONS OF COBALT–MANGANESE AND CERIUM–ZIRCONIUM AND THEIR CATALYTIC ACTIVITY IN THE DECOMPOSITION OF HYDROGEN PEROXIDE". Ukrainian Chemistry Journal 85, n.º 11 (16 de diciembre de 2019): 15–27. http://dx.doi.org/10.33609/0041-6045.85.11.2019.15-27.

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Cobalt oxides and/or manganese and their com-position based on cerium and zirconium oxides (CeO2 : ZrO2 = 1:1 mol.%) with a content of up to 20 wt. % are synthesized. Samples of both individual oxides and complex oxide compositions were prepared by precipitation from solutions of am-monia (room temperature) or hexamethylenetet-ramine (80–90 °C) followed by heat treatment. Results of DTA show, that due to the calcination at 400 ° C (2 h), the obtained samples lose 17–22 wt. % corresponding to 2–3.8 molecules of water. According to the X-ray powder analysis, initially are formed hydroxide compounds of cobalt (CoO· xH2O) and manganese (MnO2·yН2О), which, after being heated at 400 °C for 2 hours, are converted into mixed oxides from the composition of Co3O4 and Mn3O4. The average particle size calculated by the Sherer equation is 18–30 nm. In the study of catalytic activity on the example of the reaction of the hydrogen peroxide decomposition, it was found that the obtained samples from the solution of GMTA show a greater ability to catalytically decompose hydrogen peroxide compared to samples obtained from the ammonia solution. In this case, the catalytic activity of dried samples is twice as high as roasted, regardless of the method of obtaining. Samples of oxide compo-sitions with deposited 5–10 wt. % of Ce–Zr oxides (1:1) exhibit the highest ability to decompose H2O2. In this case, samples of compositions obtained from the solution of GMTA, have a prolonged catalytic action, and when precipitation in the solution of ammonia, the reaction takes place quite actively during 4–5 days. Compositions formed from co-deposited or mechanically mixed hydroxocompounds of cobalt and manganese with 5 wt. % of CeO2–ZrO2 (1:1) deposited on them have different catalytic activity. In the case of mechanically mixed, it is 30% lower and with subsequent calcination at 400 °C, it is reduced by almost half, and with co-precipitation, the activity is quite high and does not change with heat treatment. In the case of obtaining samples of Co–Mn with Ce–Zr (1:1) deposited on them in excess of 10 wt. % the catalytic activity of the samples dried at 80 °C is equal to the activity of the co-deposited hydroxocompounds of cobalt and manganese and the calcination at 400 °C it reduces it by 30 %. The best ability for catalysis was found in samples CoO·xH2O + 5 wt. % MnO2·yН2О, СоO×хН2О + 10 wt. % CeO2:ZrO2 and СоO×хН2О–MnO2×yН2О, precipitated with the GMTA solution and dried at 80 °C. The besser catalytic properties revealed a sample of СоО×хН2О + 10 wt. % CeO2:ZrO2, which with-out stirring is capable of decomposing 1.2–1.4 dm3/g of hydrogen peroxide with a rapid reaction and in the experiment the volume of H2O2 reacted was 3.4 dm3/g.

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Modrogan, Cristina, Simona Cǎprǎrescu, Annette Madelene Dǎncilǎ, Oanamari Daniela Orbuleț, Eugeniu Vasile y Violeta Purcar. "Mixed Oxide Layered Double Hydroxide Materials: Synthesis, Characterization and Efficient Application for Mn2+ Removal from Synthetic Wastewater". Materials 13, n.º 18 (15 de septiembre de 2020): 4089. http://dx.doi.org/10.3390/ma13184089.

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Magnesium–aluminum (Mg-Al) and magnesium–aluminum–nickel (Mg-Al-Ni) layered double hydroxides (LDHs) were synthesized by the co-precipitation method. The adsorption process of Mn2+ from synthetic wastewater was investigated. Formation of the layered double hydroxides and adsorption of Mn2+ on both Mg-Al and Mg-Ni-Al LDHs were observed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry (EDX) analysis. XRD patterns for prepared LDHs presented sharp and symmetrical peaks. SEM studies revealed that Mg-Al LDH and Mg-Al-Ni LDH exhibit a non-porous structure. EDX analysis showed that the prepared LDHs present uniformly spread elements. The adsorption equilibrium on these LDHs was investigated at different experimental conditions such as: Shaking time, initial Mn2+ concentration, and temperatures (10 and 20 °C). The parameters were controlled and optimized to remove the Mn2+ from synthetic wastewater. Adsorption isotherms of Mn2+ were fitted by Langmuir and Freundlich models. The obtained results indicated that the isotherm data fitted better into the Freundlich model than the Langmuir model. Adsorption capacity of Mn2+ gradually increased with temperature. The Langmuir constant (KL) value of Mg-Al LDH (0.9529 ± 0.007 L/mg) was higher than Mg-Al-Ni LDH (0.1819 ± 0.004 L/mg), at 20 °C. The final adsorption capacity was higher for Mg-Al LDH (91.85 ± 0.087%) in comparison with Mg-Al-Ni LDH (35.97 ± 0.093%), at 20 °C. It was found that the adsorption kinetics is best described by the pseudo-second-order model. The results indicated that LDHs can be considered as a potential material for adsorption of other metallic ions from wastewater.

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Ramesh, Thimmasandra Narayan. "Effect of Substituents on the Electrochemical Reversible Discharge Capacity of Cobalt Hydroxide Electrodes". Journal of New Materials for Electrochemical Systems 18, n.º 2 (30 de mayo de 2015): 091–93. http://dx.doi.org/10.14447/jnmes.v18i2.375.

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Cobalt hydroxide, nickel hydroxide-cobalt hydroxide and zinc oxide-cobalt hydroxide biphasic mixtures were prepared by precipitation method. In spite of structural similarities exhibited by nickel hydroxide and cobalt hydroxide samples, former is a good electrode material and exchanges 1e-/Ni while latter does not show any reversibility. Presence of small amount of other metal ions such as nickel or zinc in the lattice of cobalt hydroxide or as a biphasic mixture of cobalt hydroxide-nickel hydroxide/cobalt hydroxide- zinc oxide, exchange up to 0.2 to 0.24e- exchange compared to pure cobalt hydroxide which shows 0.1 e- exchange.

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12

Williams, Chelsea, William Hawker y James William Vaughan. "Selective leaching of nickel from mixed nickel cobalt hydroxide precipitate". Hydrometallurgy 138 (junio de 2013): 84–92. http://dx.doi.org/10.1016/j.hydromet.2013.05.015.

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13

Hou, Xin Gang, Wen Wu Liu, Cai Xia Li y You Fu Wang. "Preparation and Study of Spherical Nickel Hydroxide Coated by Cobalt Oxy-Hydroxide". Advanced Materials Research 668 (marzo de 2013): 383–87. http://dx.doi.org/10.4028/www.scientific.net/amr.668.383.

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Nanometer nickel hydroxide particles coated by cobalt oxy-hydroxide are prepared through chemical precipitation method. The properties of coated Ni(OH)2 particles is characterized by using X-ray diffraction, scanning electron microscopy, constant current charge/discharge test and cyclic voltammetry. Studies are focused on the effects of different amounts of cobalt oxy-hydroxide on structure and electrochemical characteristics of nickel hydroxide. The results show that a structure of β-Ni(OH)2 is preserved and 2.5 wt % CoOOH can form a well distributed conductive network on the surface of nickel hydroxide particles, thereby leading to higher utilization of active material; Compared to other electrodes, the electrodes with 2.5 wt % coated CoOOH show higher specific capacity and better cycling durability, and the electrodes also has better reversibility of the Ni(OH)2/NiOOH redox couple, and higher oxygen evolution potential.

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Gerold, Eva, Stefan Luidold y Helmut Antrekowitsch. "Selective Precipitation of Metal Oxalates from Lithium Ion Battery Leach Solutions". Metals 10, n.º 11 (29 de octubre de 2020): 1435. http://dx.doi.org/10.3390/met10111435.

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The separation of cobalt and nickel from sulfatic leach liquors of spent lithium-ion batteries is described in this paper. In addition to the base metals (e.g., cobalt and nickel), components such as manganese and lithium are also present in such leach liquors. The co-precipitation of these contaminants can be prevented during leach liquor processing by selective precipitation. For the recovery of a cobalt-nickel mixed material, oxalic acid serves as a suitable reagent. For the optimization of the precipitation retention time and yield, the dependence of the oxalic acid addition must be taken into account. In addition to efficiency, attention must also be given to the purity of the product. After this procedure, further processing of the products by calcination into oxides leads to better marketability. A series of experiments confirms the suitability of oxalic acid for precipitation of cobalt and nickel as a mixed oxalate from sulfatic liquors and also suggests a possible route for further processing of the products with increased marketability. The impurities in the resulting oxides are below 3%, whereby a sufficiently high purity of the mixed oxide can be achieved.

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15

Kursunoglu, Sait. "Synergistic effect of organic acid on the dissolution of mixed nickel-cobalt hydroxide precipitate in sulphuric acid solution". Metallurgical Research & Technology 116, n.º 3 (2019): 319. http://dx.doi.org/10.1051/metal/2018107.

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The synergistic effect of an organic acid on the dissolution of nickel and cobalt from a mixed nickel-cobalt hydroxide precipitate (MHP) in sulphuric acid solution was studied. The effects of sulphuric acid concentration, the type of organic acid, leaching time, leaching temperature and stirring speed on the dissolution of the metals were experimentally investigated. It was observed that there is no beneficial effect of leaching temperature and stirring speed on the dissolution of the metals from the used MHP product which contains 37.7% Ni, 2.1% Co and 5.6% Mn. It was found that citric acid was more effective than oxalic acid for the dissolution of nickel and manganese, whereas oxalic acid was more effective than citric acid for the dissolution of cobalt. The addition of oxalic acid into the leaching system, however, affected the dissolution of nickel negatively because nickel precipitate as nickel oxalate. Therefore, the use of citric acid as synergist for sulphuric acid leaching of MHP product is more promising. After 60 min of leaching, 90.9% Ni, 84.2% Co and 98.1% Mn were dissolved under the following conditions: 0.75 M sulphuric acid, 2 g citric acid, 1/10 solid-to-liquid ratio, 400 rpm stirring speed and 30 °C temperature. The experimental results demonstrate that the addition of citric acid as a synergist for sulphuric acid leaching of a MHP product provides beneficial effect for the dissolution of nickel, cobalt and manganese.

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Sivakumar, Periyasamy, Milan Jana, Min Gyu Jung, Aharon Gedanken y Ho Seok Park. "Hexagonal plate-like Ni–Co–Mn hydroxide nanostructures to achieve high energy density of hybrid supercapacitors". Journal of Materials Chemistry A 7, n.º 18 (2019): 11362–69. http://dx.doi.org/10.1039/c9ta02583a.

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Nanostructured mixed multi-metal compounds (NCM) based on nickel (Ni), cobalt (Co), and manganese (Mn) are considered as promising electrode materials owing to their multiple valence states, facile accessibility to active sites, and low activation energy for electron transfer.

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Feng, Yu Chuan, Shi Xi Zhao, Ce Wen Nan y Yuan Hua Lin. "Synthesis of the Layered-Spinel Intergrowth Structure Cathode Materials by Co-Precipitation Method". Advanced Materials Research 105-106 (abril de 2010): 668–72. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.668.

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Cathode materials Li-[MnxNi1/2-x/2Co1/2-x/2]-O (x=0.333, 0.4, 0.6, 0.8, 0.9) were fabricated by lithium salts (LiNO3) and manganese-nickel-cobalt hydroxide precursors using the required amounts of Mn, Ni, Co for a given value of x. When Mn content is between 0.5 and 0.8, layered and spinel structure co-existed. Meanwhile the rate Li/M is also a key factor for synthesis of layered-spinel intergrowth structure cathode materials without other impurities. Li-[Ni0.2Co0.2Mn0.6]-O and Li-[Ni0.1Co0.1Mn0.8]-O were synthesized by a Two-step Co-precipitation method.

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Jones, Andrew N. y Nicholas J. Welham. "Properties of aged mixed nickel–cobalt hydroxide intermediates produced from acid leach solutions and subsequent metal recovery". Hydrometallurgy 103, n.º 1-4 (junio de 2010): 173–79. http://dx.doi.org/10.1016/j.hydromet.2010.03.017.

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Shamraiz, Umair, Rukhsana Gul, Amin Badshah y Bareera Raza. "Retention of anions in cobalt hydroxide with Ni substitution to emphasize the role of anions and cations for high current density in oxygen evolution reactions". Dalton Transactions 49, n.º 46 (2020): 16962–69. http://dx.doi.org/10.1039/d0dt03200j.

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Soylak, Mustafa, Ayse Aydin y Nebiye Kizil. "Multi-Element Preconcentration/Separation of Some Metal Ions in Environmental Samples by Using Co-precipitation". Journal of AOAC INTERNATIONAL 99, n.º 1 (1 de enero de 2016): 273–78. http://dx.doi.org/10.5740/jaoacint.11-0214.

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Abstract A preconcentration/separation system for cadmium(II), nickel(II), copper(II), lead(II), iron(II), cobalt(II), and manganese(II) ions has been established prior to their atomic absorption spectrometric determinations. The procedure is based on the co-precipitation of these ions by the aid of a praseodymium hydroxide (Pr(OH)3) precipitate. The precipitate was dissolved in 0.5 mL of concentrated HNO3, and made up to 10.0 mL with water. The analytes were determined by a flame atomic absorption spectrometer. The effects of analytical parameters including pH, amounts of praseodymium as carrier element, sample volume, etc. on the recoveries of heavy metals were investigated. The effects of matrix ions were also examined. The limits of detection for analyte ions were found in the range between 0.7–5.2 μg/L. The validation of this present procedure was verified by the analysis of certified reference materials, TMDA-54.4 (fortified water) and NIST 1570a (spinach leaves). The proposed co-precipitation procedure was applied for the determination of cadmium(II), nickel(II), copper(II), lead(II), iron(II), cobalt(II), and manganese(II) ions in various environmental water samples.

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Xu, Hui, Junxia Wu, Jian Liu, Yong Chen y Xin Fan. "Growth of cobalt–nickel layered double hydroxide on nitrogen-doped graphene by simple co-precipitation method for supercapacitor electrodes". Journal of Materials Science: Materials in Electronics 29, n.º 20 (28 de agosto de 2018): 17234–44. http://dx.doi.org/10.1007/s10854-018-9817-2.

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Abbasi, Samaneh, Farzaneh Hekmat y Saeed Shahrokhian. "Beyond hierarchical mixed nickel-cobalt hydroxide and ferric oxide formation onto the green carbons for energy storage applications". Journal of Colloid and Interface Science 593 (julio de 2021): 182–95. http://dx.doi.org/10.1016/j.jcis.2021.02.080.

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Zhang, Dong Yun, Juan Yi, Qun Wei, Kun Liu, Zhen Zhen Fan y Pei Xin Zhang. "Study on the Rate Performance of LiCo_1/3Ni_1/3Mn_1/3O₂". Advanced Materials Research 158 (noviembre de 2010): 256–61. http://dx.doi.org/10.4028/www.scientific.net/amr.158.256.

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Ternary lithium-ion battery is currently one of the hot cathode materials. In this paper, with acetate of nickel, manganese and cobalt as raw materials and lithium hydroxide as precipitation agent, LiCo1/3Mn1/3Ni1/3O2 was prepared by chemical coprecipitation method. LAND charge-discharge testing was used to study the electrochemical performance of materials at different rates (0.5C, 1C, 2C), and AC impedance spectroscopy was employed to study the rate performance and reasons of cyclical stability. The results showed that the stable SEM film formed under high rate was the main reason for the increased rate.

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Maca, T., J. Vondrak, M. Sedlarikova y L. Nezgoda. "Effect of Cobalt Addition on Structure and Electrochemical Behaviour of Nickel Hydroxide Synthesized by Chemical Precipitation Method under Different Conditions". ECS Transactions 48, n.º 1 (21 de enero de 2014): 7–15. http://dx.doi.org/10.1149/04801.0007ecst.

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Naalchian, Mojtaba, Masoud Kasiri-Asgarani, Morteza Shamanian, Reza Bakhtiari, Hamid Reza Bakhsheshi-Rad, Filippo Berto y Oisik Das. "Phase Formation during Heating of Amorphous Nickel-Based BNi-3 for Joining of Dissimilar Cobalt-Based Superalloys". Materials 14, n.º 16 (16 de agosto de 2021): 4600. http://dx.doi.org/10.3390/ma14164600.

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Phase transformations and the melting range of the interlayer BNi-3 were investigated by differential scanning calorimetry, which showed three stages of crystallization during heating. There were three exothermic peaks that indicated crystallization in the solid state. The cobalt-based X-45 and FSX-414 superalloys were bonded with interlayer BNi-3 at a constant holding time of 10 min with bonding temperatures of 1010, 1050, 1100, and 1150 °C using a vacuum diffusion brazing process. Examination of microstructural changes in the base metals with light microscopy and scanning electron microscopy coupled with X-ray spectroscopy based on the energy distribution showed that increasing temperature caused a solidification mode, such that the bonding centerline at 1010 °C/10 min included a γ-solid solution, Ni3B, Ni6Si2B, and Ni3Si. The athermally solidified zone of the transient liquid phase (TLP)-bonded sample at 1050 °C/10 min involved a γ-solid solution, Ni3B, CrB, Ni6Si2B, and Ni3Si. Finally, isothermal solidification was completed within 10 min at 1150 °C. The diffusion-affected zones on both sides had three distinct zones: a coarse block precipitation zone, a fine and needle-like mixed-precipitation zone, and a needle-like precipitation zone. By increasing the bonding temperature, the diffusion-affected zone became wider and led to dissolution.

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Adan-Mas, Alberto, Pablo Arévalo-Cid, Teresa Moura e Silva, João Crespo y Maria de Fatima Montemor. "From Bench-Scale to Prototype: Case Study on a Nickel Hydroxide—Activated Carbon Hybrid Energy Storage Device". Batteries 5, n.º 4 (15 de octubre de 2019): 65. http://dx.doi.org/10.3390/batteries5040065.

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Hybrid capacitors have been developed to bridge the gap between batteries and ultracapacitors. These devices combine a capacitive electrode and a battery-like material to achieve high energy-density high power-density devices with good cycling stability. In the quest of improved electrochemical responses, several hybrid devices have been proposed. However, they are usually limited to bench-scale prototypes that would likely face severe challenges during a scaling up process. The present case study reports the production of a hybrid prototype consisting of commercial activated carbon and nickel-cobalt hydroxide, obtained by chemical co-precipitation, separated by means of polyolefin-based paper. Developed to power a 12 W LED light, these materials were assembled and characterized in a coin-cell configuration and stacked to increase device voltage. All the processes have been adapted and constrained to scalable conditions to ensure reliable production of a pre-commercial device. Important challenges and limitations of this process, from geometrical constraints to increased resistance, are reported alongside their impact and optimization on the final performance, stability, and metrics of the assembled prototype.

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Feng, Zhange, Pallab Barai, Jihyeon Gim, Ke Yuan, Yimin A. Wu, Yuanyuan Xie, Yuzi Liu y Venkat Srinivasan. "In Situ Monitoring of the Growth of Nickel, Manganese, and Cobalt Hydroxide Precursors during Co-Precipitation Synthesis of Li-Ion Cathode Materials". Journal of The Electrochemical Society 165, n.º 13 (2018): A3077—A3083. http://dx.doi.org/10.1149/2.0511813jes.

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28

Imran Din, Muhammad, Faria Rafique, Muhammad Sadaf Hussain, Hafiz Arslan Mehmood y Sadia Waseem. "Recent developments in the synthesis and stability of metal ferrite nanoparticles". Science Progress 102, n.º 1 (marzo de 2019): 61–72. http://dx.doi.org/10.1177/0036850419826799.

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This article presents a comprehensive review on the synthesis and stability of ferrite nanoparticles such as nickel ferrite (NiFe2O4), zinc ferrite (ZnFe2O4), manganese ferrite (MnFe2O4), iron ferrite (Fe2O3), cobalt ferrite (CoFe2O4) and also mixed nanoparticles. Different synthetic methods for ferrite nanoparticles have been reviewed such as co-precipitation, thermal decomposition and hydrothermal, microwave-assisted and sonochemical methods. The effect on the stability of different capping agents like canola oil, glycerol, sodium dodecyl, sodium citrate, oleic acid, Triton-100 and sodium dodecyl benzene sulfonates has also been studied.

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29

Sharma, J. K., Pratibha Srivastava, Gurdip Singh y Hardev Singh Virk. "Nanoferrites of Transition Metals and their Catalytic Activity". Solid State Phenomena 241 (octubre de 2015): 126–38. http://dx.doi.org/10.4028/www.scientific.net/ssp.241.126.

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Recent applications of transition metal nanoferrites as catalyst in thermal decomposition of ammonium perchlorate (AP) and combustion of composite solid propellant (CSP), have been reviewed. Catalytic applications include the use of mainly cobalt, nickel, copper, zinc, manganese, cadmium nanoferrites, as well as their mixed-metal combinations. The nanoferrites are obtained mainly by wet-chemical, sol-gel, solvo-thermal, auto-combustion and co-precipitation methods. Addition of nanoferrites to AP led to shifting of the high temperature decomposition peak toward lower temperatures which shows their catalytic activity. The burning rates of CSPs have also been enhanced by these nanoferrites. Contents of Paper

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30

Kaczorowski, M., P. Skoczylas, A. Krzyńska y J. Kaniewski. "The Strengthening of Weight Heavy Alloys During Heat Treatment". Archives of Foundry Engineering 12, n.º 4 (1 de diciembre de 2012): 75–80. http://dx.doi.org/10.2478/v10266-012-0110-1.

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Abstract The results of studies of W-Ni-Co-Fe experimental alloy, with chemical composition assuring a possibility of producing Ni-based supersaturated solid solution are presented. The alloy was prepared from tungsten, nickel, cobalt and iron powders which were first mixed then melted in a ceramic crucible where they slowly solidified in hydrogen atmosphere. Next specimens were cut from the casting and heated at a temperature 950°C. After solution treatment the specimens were water quenched and then aged for 20 h at a temperature 300°C. The specimens were subjected to microhardness measurements and structure investigations. The latter included both conventional metallography and SEM observations. Moreover, for some specimens X-ray diffractometry studies and TEM investigations were conducted. It was concluded that quenching lead to an increase of tungsten concentration in nickel matrix which was confirmed by Ni lattice parameter increase. Aging of supersaturated solid solution caused strengthening of the Ni-based matrix, which was proved by hardness measurements. The TEM observation did not yield explicit proofs that the precipitation process could be responsible for strengthening of the alloy

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31

Deshmane, Vikas V. y Arun V. Patil. "Effects of Additives on Structural and Magnetic Properties of Iron Oxide". International Journal of Nanoscience 19, n.º 04 (24 de marzo de 2020): 1950025. http://dx.doi.org/10.1142/s0219581x1950025x.

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This paper analyzes the effects of additives on the properties of Iron oxide. The Iron oxide was synthesized using the co-precipitation method. The X-ray diffraction (XRD) peaks of resultant Iron oxide perfectly matched with JCPDS #860550 ([Formula: see text] phase of Iron oxide / Hematite). The additives like Cobalt oxide, Nickel metal, Indium oxide and Tin metal with diverse properties procured in readymade forms were mechanically mixed with Iron oxide in 1:99, 3:97, 5:95 and 7:93 weight ratios, respectively. The XRD peaks for additives were prominent for 7:93 (Additive: Base Material) weight % ratio samples. Therefore, for further studies, only these samples were used. In this study, variations in XRD intensity, lattice parameters, unit cell volume, grain size, micro-strains (W-H analysis), dislocation density and stacking fault probability were analyzed. The specific surface area of particles was calculated by scanning electron microscope analysis. The presence of additives was also confirmed by energy dispersive spectra (EDS). The M-H loops (Vibrating Sample Magnetometer analysis) for samples under investigation showed rare vertical shifts. The weak magnetic behavior of bare Hematite (1.0 emu/gm) sample improved to antiferromagnetic behavior due to the addition of Cobalt oxide (7.89 emu/gm) and Nickel metal (2.76 emu/gm). The addition of Indium oxide (0.65 emu/gm) and Tin metal (0.73 emu/gm) samples showed a decreased magnetic saturation.

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32

Ali Saleh, Rezan, Hikmat Ali Mohammad y Salim Najm Aldin Saber. "New Mixed Ligand Cobalt(II), Nickel(II) and Copper(II) Complexes of 2,2'-Bipyridine-3,3'-Dicarboxylic acid (bpdc) with 2-Mercapto-5-Phenyl-1,3,4-Oxadiazole (phozSH) and Their Antioxidant activity". Oriental Journal Of Chemistry 36, n.º 05 (25 de octubre de 2020): 834–42. http://dx.doi.org/10.13005/ojc/360506.

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The mixing of one mole of 2,2'-bipyridine-3,3'-dicarboxylic acid (bpdc) with two mole of potassium hydroxide (KOH) in methanol were refluxed for (half hour), followed by addition of one mole methanol solution of MCl2.nH2O (where M=Co, Ni or Cu). The mixture was refluxed for (2 hours) to give colored complexes of the metal ions of [M(bpdc)(H2O)4]. The [M(bpdc)(H2O)4] were reacted with one mole of 2-Mercapto-5-phenyl-1,3,4-oxadiazole (phozSH) producing the colored mixed ligand complexes with general formula [M(bpdc)(phozSH)(H2O)3] in which the metal ions coordinated to the ligand through O-atoms of carboxyl group in (bpdc) and N-atom of (phozSH) ligand. The ligands and complexes are well identified by using Furrier transform infrared spectroscopy, 1H-NMR, 13C-NMR, Electronic spectroscopy, CHNS analysis, Melting point, conductivity measurement. The Antioxidant activity were screened for all the complexes by the use of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method.

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33

Klimko, Jakub, Dušan Oráč, Andrea Miškufová, Claudia Vonderstein, Christian Dertmann, Marcus Sommerfeld, Bernd Friedrich y Tomáš Havlík. "A Combined Pyro- and Hydrometallurgical Approach to Recycle Pyrolyzed Lithium-Ion Battery Black Mass Part 2: Lithium Recovery from Li Enriched Slag—Thermodynamic Study, Kinetic Study, and Dry Digestion". Metals 10, n.º 11 (23 de noviembre de 2020): 1558. http://dx.doi.org/10.3390/met10111558.

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Due to the increasing demand for battery raw materials, such as cobalt, nickel, manganese, and lithium, the extraction of these metals, not only from primary, but also from secondary sources, is becoming increasingly important. Spent lithium-ion batteries (LIBs) represent a potential source of raw materials. One possible approach for an optimized recovery of valuable metals from spent LIBs is a combined pyro- and hydrometallurgical process. The generation of mixed cobalt, nickel, and copper alloy and lithium slag as intermediate products in an electric arc furnace is investigated in part 1. Hydrometallurgical recovery of lithium from the Li slag is investigated in part 2 of this article. Kinetic study has shown that the leaching of slag in H2SO4 takes place according to the 3-dimensional diffusion model and the activation energy is 22–24 kJ/mol. Leaching of the silicon from slag is causing formation of gels, which complicates filtration and further recovery of lithium from solutions. The thermodynamic study presented in the work describes the reasons for the formation of gels and the possibilities of their prevention by SiO2 precipitation. Based on these findings, the Li slag was treated by the dry digestion (DD) method followed by dissolution in water. The silicon leaching efficiency was significantly reduced from 50% in the direct leaching experiment to 5% in the DD experiment followed by dissolution, while the high leaching efficiency of lithium was maintained. The study takes into account the preparation of solutions for the future trouble-free acquisition of marketable products from solutions.

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34

Miao, Chao Lin, Lu Shi, Gai Rong Chen y Dong Mei Dai. "Preparation of Precursor of Lini0.5mn1.5o4 with High Density". Advanced Materials Research 463-464 (febrero de 2012): 881–84. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.881.

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The precursor of LiNi0.5MnSubscript text1.5O4cathode material with high density was synthesized by two-dryness co-precipitation method. The optimized parameters were found out by studying the relationship between the density of precursor and the concentration of reactants, the manner of adding agglomerating agent, the remaining water in filter cake and the manner of dryness. The highest density (1.74 g/cm3) of precursor can be achieved under optimized condition: NiSO40.375 mol/L, coagulation agent added with little amount but many times, 28% of water in filter cake and two-step dryness, which is much better than that made by other methods. Our experiment provides a significant reference for the synthesis of excellent-performance cathode materials of lithium-ion battery. LiNi0.5MnSubscript text1.5O4has a good cycle performance, a higher discharge capacity and a discharge platform of 4.7v, so it has become a research focus of 5-voltage cathode materials in the field of lithium ion battery recently.[1-4] However, LiNi0.5Mn1.5O4 prepared by common methods usually has a lower tap volume capacity.[5-9] HiroyuKi Ito[6] reported a continuous fabricated high-density cobalt-manganese-doped nickel hydroxide method with which the density of product was between 1.5-1.91g/cm3, however the used ammonia as a complexation agent in the preparation process not only increased the cost of the preparation, but also led to environmental pollution. Research results show that the cathode material synthesized using high-density precursor has a higher tap density, a larger volume capacity and a good electrochemical performance.[10] In this paper, we find out the optimized parameters of preparation of precursor of LiNi0.5MnSubscript text1.5O4by studying the relationship between the density of precursor and concentration of reactants, the manner of adding agglomerating agent, the remaining water in filter cake and the manner of dryness.

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35

Kurşunoglu, Sait. "EXTRACTION OF NICKEL FROM A MIXED NICKEL-COBALT HYDROXIDE PRECIPITATE". Bilimsel Madencilik Dergisi, 1 de marzo de 2019, 45–52. http://dx.doi.org/10.30797/madencilik.537644.

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36

Ma, Miaomiao, Natasha A. Chernova, Peter Y. Zavalij y M. Stanley Whittingham. "Structural and Electrochemical Properties of LiMn0.4Ni0.4Co0.2O2". MRS Proceedings 835 (2004). http://dx.doi.org/10.1557/proc-835-k11.3.

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ABSTRACTThe layered oxide LiMn0.4Ni0.4Co0.2O2 was synthesized by heating the mixed hydroxide precursor. This 442 composition was found to show high capacity. It has the optimum cobalt concentration to both substantially order the lattice, yet leave enough nickel on the lithium sites to minimize conversion to the 1T structure of CoO2 on deep charging. A combined x-ray and neutron diffraction study showed conclusively that only nickel, not manganese or cobalt is found on the lithium sites at room temperature. Magnetic measurements also confirmed the presence of nickel on the lithium sites, and showed the effectiveness of cobalt at minimizing nickel disorder. Heating above 800°C always leads to nickel disorder. The structural and thermal stability of reduced lithium content materials was studied; the structure remains rhombohedral except for x≤0.05, and cobalt substitution improves the thermal stability of the layered compound, but not the chemical stability.

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37

"Novel Method for Synthesis of High Nickel Cobalt Aluminum Hydroxide By Engineered Two Step Co-Precipitation Method". ECS Meeting Abstracts, 2015. http://dx.doi.org/10.1149/ma2015-01/2/488.

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38

"Evolution of Nickel, Manganese, and Cobalt Hydroxide Precursor for Li-Ion Battery Cathode Materials in Co-Precipitation Reactions". ECS Meeting Abstracts, 2018. http://dx.doi.org/10.1149/ma2018-01/1/59.

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39

Hussaini, Shokrullah, Zela Tanlega Ichlas, Soner Top, Sait Kursunoglu y Muammer Kaya. "Selective leaching of a mixed nickel-cobalt hydroxide precipitate in sulphuric acid solution with potassium permanganate as oxidant". Separation Science and Technology, 12 de octubre de 2020, 1–10. http://dx.doi.org/10.1080/01496395.2020.1832523.

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40

Akhtar, Khalida, Hina Khalid, Ikram Ul Haq, Naila Zubair, Zia Ullah Khan y Abid Hussain. "Tribological Properties of Electrodeposited Ni–Co3O4 Nanocomposite Coating on Steel Substrate". Journal of Tribology 139, n.º 6 (30 de junio de 2017). http://dx.doi.org/10.1115/1.4036450.

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Uniform nanoparticles of cobalt oxide precursors were prepared by the chemical precipitation in which the headspace vapors of ammonium hydroxide solution of known concentration were allowed to bubble through the aqueous solutions of cobalt sulfate, containing appropriate amount of the nonionic surfactant, octylphenoxy poly ethoxy ethanol. Scanning electron microscope (SEM) images showed that uniformity in particle size was dependent upon the applied precipitation conditions. Extensive optimization was therefore performed for the attainment of uniformity in particle size and shape. The amorphous precursor was transformed into crystalline Co3O4 as confirmed by X-ray diffractometry. These particles, with isoelectric point (IEP) at pH ∼ 8.4, were then employed as reinforcement additive for strengthening the electrodeposited nickel matrix. Effect of various parameters, i.e., stirring rate, applied current density, and temperature, was studied on the amount of the codeposited Co3O4 particles in the nanocomposite coatings (Ni–Co3O4) during the electrodeposition process. pH of the coating mixtures was kept below IEP value of Co3O4 so that the latter particles carried net positive surface charge. The coated surfaces were subjected to various tests, i.e., microhardness, wear/friction, and corrosion. Results revealed that irrespective of the amount of the embedded Co3O4 particles, nanocomposite coatings demonstrated superior performance as compared to pure nickel coatings.

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41

Kitenge, V. N., K. O. Oyedotun, O. Fasakin, D. J. Tarimo, N. F. Sylla, X. Van Heerden y N. Manyala. "Enhancing the electrochemical properties of a nickel–cobalt-manganese ternary hydroxide electrode using graphene foam for supercapacitors applications". Materials for Renewable and Sustainable Energy 10, n.º 1 (marzo de 2021). http://dx.doi.org/10.1007/s40243-021-00192-y.

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AbstractThis study has investigated the effect of the incorporation of graphene foam (GF) into the matrix of a ternary transition-metals hydroxide containing nickel, cobalt, and manganese for optimal electrochemical performances as electrodes for supercapacitors applications. An adopted simple, low-cost co-precipitation synthesis method involved the loading a mass of the ternary metal hydroxides (NiCoMn-TH) onto various GF mass loading so as to find ints effect on the electrochemical properties of the hydroxides. Microstructural and chemical composition of the various composite materials were investigated by employing scanning/transmission electron microscopy (SEM/TEM), x-ray diffraction (XRD), Raman spectroscopy, and N2 physisorption analysis among others. Electrochemical performances of the NiCoMn-TH/200 mg GF composite material evaluated in a three-electrode system using 1 M KOH solution revealed a maximum specific capacity around 178.6 mAh g−1 compared to 76.2 mAh g−1 recorded for the NiCoMn-TH pristine material at a specific current of 1 A g−1. The best mass loading of GF nanomaterial (200 mg GF), was then utilised as a positive electrode material for the design of a novel hybrid device. An assembled hybrid NiCoMn-TH/200 mg GF//CSDAC device utilizing the NiCoMn-TH/200 mg GF and activated carbon derived from the cocoa shell (CSDAC) as a positive and negative electrode, respectively, demonstrated a sustaining specific capacity of 23.4 mAh g−1 at a specific current of 0.5 A g−1. The device also yielded sustaining a specific energy and power of about 22.32 Wh kg−1 and 439.7 W kg−1, respectively. After a cycling test of over 15,000 cycles, the device could prove a coulombic efficiency of ~ 99.9% and a capacity retention of around 80% within a potential range of 0.0–1.6 V at a specific current of 3 A g−1. These results have demonstrated the prodigious electrochemical potentials of the as-synthesized material and its capability to be utilized as an electrode for supercapacitor applications.

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42

"Sulfuration treatment of electroplating wastewater for selective recovery of copper, zinc and nickel resource". Issue 2 8, n.º 2 (29 de abril de 2013): 131–36. http://dx.doi.org/10.30955/gnj.000349.

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In the electroplating process, various metal salts are used and the residues on the surface of electroplated materials are rinsed out as wastewater, followed by hydration in a wastewater disposal step. Although a variety of metals are concentrated in the sludge, the mixed heterogeneous state of these metals in sludge makes it difficult to recycle and reuse them. From the viewpoint of environmental protection as well as resource saving, effective methods for recycling and reuse of these mixed metal sludge are required to be developed urgently. In the present work, selective recovery of the metals from mixed-metal wastewater by sulfuration treatment is proposed. Sulfuration treatment is characterized by low solubility of metal sulfides; metal sulfides are, in general, lower in solubility than that of metal hydroxides. For the experiments, three metals of copper, zinc and nickel which are commonly used in the electroplating process were chosen. Separation of these metals from the mixed solution in various pH ranges was conducted by employing three sulfurating agents: sodium sulfide (Na2S), sodium disulfide (Na2S2) and sodium tetrasulfide (Na2S4). Aqueous solutions of CuSO4, ZnSO4 and NiSO4 and those of real plating wastewater, of which the initial concentrations were adjusted to 100-300 mg dm-3 were employed. By sulfuration treatment of the simulated solution using each sulfurating agent without adjusting pH, CuS was first precipitated, but ZnS and NiS were also precipitated at the same time. In addition, pH value increased with the amount of sulfurating agents in the solution. The results demonstrated that the formation behavior of metal precipitates depended on pH value of the solution. For the sulfuration with three kinds of sulfurating agents, copper was first separated from the solution as CuS in pH=1.4-1.5, then ZnS was precipitated in pH=2.4-2.5, followed by the precipitation of nickel sulfide, NiS in the residual solution at pH=5.5-6.0. It was also found that Na2S is most effective for selective precipitation of metal sulfides, among the three sulfurating agents of Na2S, Na2S2 and Na2S4. The selectivity of CuS in the filtrated cake obtained by the sulfuration treatment in pH=1.4-1.5 was about 94 % and was sufficiently high, in terms of allowable metal content level for recycling. The sequent selectivity of ZnS and NiS in the cake after the sulfuration treatment in pH=2.4-2.5 were 75-77 % and about 20 %, respectively. The selectivity of NiS and ZnS in the cake after the sulfuration treatment in pH=5.5-6.0 was 64-66 % and 33-35 %, respectively.

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43

Gordon, Roy G., Feng Chen, Nicholas J. Diceglie, Amos Kenigsberg, Xinye Liu, Daniel J. Teff y John Thornton. "New Liquid Precursors for Chemical Vapor Deposition". MRS Proceedings 495 (1997). http://dx.doi.org/10.1557/proc-495-63.

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ABSTRACTNew precursors have been found for chemical vapor deposition (CVD) of many metal oxides. Each precursor is a mixture formed by randomly attaching a selected set of organic groups, such as the isomers of the butyl group, to a metal 2,4-pentanedionate (also known as acetylacetonate) in place of the methyl groups of the 2,4-pentanedionate ligand. Most of these new mixed metal beta-diketonates are liquids at room temperature, whereas the corresponding metal 2,4-pentanedionates are solids. In the cases where they were solids or viscous liquids, small amounts of organic solvents were added to reduce the viscosity. We have so far prepared mixed beta-diketonate precursors for barium, strontium, calcium, magnesium, aluminum, indium, tin, lead, bismuth, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, manganese, iron, ruthenium, cobalt, nickel, copper, zinc, yttrium, lanthanum and cerium.Liquid sources are much more convenient for CVD than solid sources. These liquid mixtures or solutions were vaporized by ultrasonically nebulizing the liquid into a flow of hot nitrogen carrier gas preheated to 150–250 °C. These vapor mixtures were mixed with air or oxygen and flowed over substrates heated typically to 350–450 °C. Films of the corresponding metal oxide (or carbonate, in the case of barium, strontium and calcium) were deposited on substrates of silicon or glass. Gas pressures from 20–760 Torr were used.Because a common set of ligands is used for each of these metal precursors, they can be mixed as liquids or vapors without any precipitation due to ligand exchange reactions. To demonstrate their use in forming mixed metal oxides, we have prepared films of ferroelectric barium titanate. This method should be applicable to other mixed metal oxides of current interest, such as high dielectric constant strontium titanate, ferroelectric bismuth strontium tantalate, superconducting yttrium barium copper oxide, refractory yttrium zirconium oxide, second-harmonic generating barium borate, metallic lanthanum strontium cobalt oxide and magnetoresistive lanthanum strontium manganate.

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González, Cesar M. Oliva, Ana de Monserrat Navarro Tellez, Boris I. Kharisov, Juan Marcos Guillén Hernández, Thelma E. Serrano Quezada, Lucy T. González y Idalia Gómez de la Fuente. "Mixed-metal MOF-derived carbon sponges for oil absorption." Recent Patents on Nanotechnology 15 (20 de enero de 2021). http://dx.doi.org/10.2174/1872210515666210120120331.

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Aims: In this work, we propose the implementation of three carbon sponges, generated from the carbonization of melamine-formaldehyde sponges coated with different HKUST-type metal-organic frameworks (MOFs) in different thermal conditions. Background: Nowadays, numerous investigations are focused on the development of new technologies for the rapid separation of water/oil mixtures. Several these processes use hydrophobic materials of different nature for efficient oil capture. Despite these efforts, the water/oil separation still remains a great challenge. The main oil absorbers that are commercially available tend to be expensive and have complex synthesis; however, they usually have an acceptable cost/benefit ratio. Despite this, the passage of time has brought us new generations of materials, which seek to solve the problems in a more efficient way, as in the case of metal-organic frameworks (MOFs), which stand out for the great ease with which their morphological and surface aspects can be controlled. MOFs are extensively investigated in the fields of adsorption and catalysis; the MOF coated sponges do not meet the selectivity and stability standards to be applied in oil spills in water. However, this completely changes when subjected to the pyrolysis process, giving the material an increase in its surface area, hydrophobic and magnetic properties in addition to making the material suitable for this application. Objective: Creation of a low-cost 3D template and the study of morphological properties of MOFs, for the formation of carbon-based materials by a fast, simple and low-cost method, promoting the use of new generations of materials to more effectively solve persistent environments. Methods: The employed MOF precursors are trimesic acid (BTC), nickel and cobalt salts. The monometallic HKUST type MOFs were synthesized using a simple method of controlled precipitation, which starts from two precursor solutions. The first one consisted of a ligand solution, dissolving the BTC in deionized water. In the case of mixed-metal MOFs, they were synthesized using the same procedure described for monometallic MOFs, but in this case a mixture of metal salts with a 1:1 molar ratio was performed. The methodology for the production of the sponges decorated with MOF was carried out in two steps. In the first stage, the sponges were subjected to a wash to remove dust and impurities, being rinsed with acetone in an ultrasonic bath for 30 min. The sponges were subsequently immersed in deionized water and subjected to an ultrasonic bath for 10 min. Finally, the sponges were dried at 60°C for 3 h. The second step is the addition of the HKUST-type MOFs to the sponges was carried out by means of the immersion method, preparing a dispersion of the corresponding MOFs in ethanol. Results: It was revealed that the carbon sponges can selectively absorb the oil in the water/oil mixture, possessing magnetic and enhanced hydrophobic and super hydrophobic properties. All the pyrolyzed carbon sponges, obtained at 500 and 700°C, were not the most optimal since they had absorption capacities of around 25 g/g and only supported up to 4 absorption cycles. On the other hand, the carbon sponges, obtained at 300°C, had absorption capacities greater than 40 g/g, in addition to being able to be reused up to 12 times without showing significant changes in their absorption capacity and having acceptable hydrophobic characteristics for the removal of oil dispersed in water. Among the three sponges obtained at 300°C, we highlight the sponges coated with BTC-Co which have the highest absorption capacity (54 g/g) among all fabricated sponges. Conclusions: The sponges obtained in the present work are a promising alternative to the materials that are traditionally used, since they have great advantages such as their simple production method, low-cost starting materials and good absorption capacities. This work sheds light on the production of carbon materials from 3D templates decorated with MOFs, through a one-step carbonization process and we demonstrate that these materials have characteristics that make them applicable in the removal of oil dispersed in water, giving us a practical, economic and friendly alternative to the environment.

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