Journal articles: 'Oxyde de cobalt'

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Ved, M. V. "Functional mixed cobalt and aluminum oxide coatings for environmental safety." Functional materials 24, no. 2 (June 22, 2017): 005–310. http://dx.doi.org/10.15407/fm24.02.303.

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Mammadyarova, S. J. "SYNTHESIS AND CHARACTERIZATION OF COBALT OXIDE NANOSTRUCTURES. A BRIEF REVIEW." Azerbaijan Chemical Journal, no. 2 (June 29, 2021): 80–93. http://dx.doi.org/10.32737/0005-2531-2021-2-80-93.

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The newest achievement in the synthesis of cobalt oxide nanoparticles are considered. Cobalt oxide nanoparticles have attracted a great attention due to their uncommon properties and application in a supercapacitor, optoelectronic device, Li-ion battery gas sensor and electrochromic devices. Recently, nanostructured transition metal oxides with valuable properties have become a new class of materials for many technological fields. Cobalt oxide nanoparticles obtained from various precursors show different size distribution as well as different optical, electrical, magnetic, and electrochemical properties. A reduction in particle size to nanometer-scale leads to changes in properties compared to bulk ones due to quantum size effects. Depending on the application area, the choice of an appropriate synthesis method for nanoparticles with desirable properties is a crucial factor. This work aims to provide additional information on the synthesis methods and properties of cobalt oxide nanoparticles

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Chansaengsri, Kasidid, Korakot Onlaor, Thutiyaporn Thiwawong, and Benchapol Tunhoo. "Supercapacitive Properties of Cobalt Oxide Thin Films Prepared by Electrostatic Spray Deposition Technique at Different Substrate Temperature." Key Engineering Materials 675-676 (January 2016): 261–64. http://dx.doi.org/10.4028/www.scientific.net/kem.675-676.261.

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In this work, cobalt oxide thin films were prepared by electrostatic spray deposition (ESD) technique. The influence of the substrate temperatures on properties of film was investigated. Phase transformation of cobalt oxide thin films due to the effect of different substrate temperature was also observed. Cyclic voltammetry was used to measure the performance of cobalt oxide supercapacitor. At higher substrate temperature, the cobalt oxide thin films exhibit the high specific capacitance due to the effect of phase transformation in cobalt oxide films.

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Mirzaeian, Mojtaba, Nazym Akhanova, Maratbek Gabdullin, Zhanar Kalkozova, Aida Tulegenova, Shyryn Nurbolat, and Khabibulla Abdullin. "Improvement of the Pseudocapacitive Performance of Cobalt Oxide-Based Electrodes for Electrochemical Capacitors." Energies 13, no. 19 (October 8, 2020): 5228. http://dx.doi.org/10.3390/en13195228.

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Cobalt oxide nanopowders are synthesized by the pyrolysis of aerosol particles of water solution of cobalt acetate. Cobalt nanopowder is obtained by subsequent reduction of obtained cobalt oxide by annealing under a hydrogen atmosphere. The average crystallite size of the synthesized porous particles ranged from 7 to 30 nm, depending on the synthesis temperature. The electrochemical characteristics of electrodes based on synthesized cobalt oxide and reduced cobalt oxide are investigated in an electrochemical cell using a 3.5 M KOH solution as the electrolyte. The results of electrochemical measurements show that the electrode based on reduced cobalt oxide (Re-Co3O4) exhibits significantly higher capacity, and lower Faradaic charge–transfer and ion diffusion resistances when compared to the electrodes based on the initial cobalt oxide Co3O4. This observed effect is mainly due to a wide range of reversible redox transitions such as Co(II) ↔ Co(III) and Co(III) ↔ Co(IV) associated with different cobalt oxide/hydroxide species formed on the surface of metal particles during the cell operation; the small thickness of the oxide/hydroxide layer providing a high reaction rate, and also the presence of a metal skeleton leading to a low series resistance of the electrode.

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Chansaengsri, Kasidid, Korakot Onlaor, Thutiyaporn Thiwawong, and Benchapol Tunhoo. "Effect of Substrate Temperature of on Properties of Cobalt Oxide Thin Films Prepared by Electrostatic Spray Deposition Technique." Applied Mechanics and Materials 848 (July 2016): 103–6. http://dx.doi.org/10.4028/www.scientific.net/amm.848.103.

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In this work, the influence of the substrate temperature on properties of cobalt oxide thin films has been reported. Cobalt oxide thin films were prepared by electrostatic spray deposition technique on glass substrate at different temperature of the substrate. The properties of cobalt oxide films were characterized by X-Ray diffraction (XRD), scanning electron microscope, Raman spectroscopy, UV-visible spectrophotometer, respectively. In additional, the crystalline structural parameters can be performed from XRD data. Phase transformation of cobalt oxide films due to different substrate temperature was observed. Moreover, the optical properties of films were depended on the quantity of phase transition in cobalt oxide film.

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Lin, Chuen-Chang, You-Lun Shen, and An-Na Wu. "The Effects of Power Levels/Time Periods for Sputtering Cobalt onto Carbon Nanotubes/Graphene Composites and Cobalt Annealed on the Characteristics of Anode Materials for Lithium-Ion Batteries." Journal of Nanomaterials 2018 (October 16, 2018): 1–11. http://dx.doi.org/10.1155/2018/9489042.

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Carbon nanotubes/graphene composites are directly grown on nickel foil without additional catalysts by chemical vapor deposition (CVD). Next, the cobalt is deposited on carbon nanotubes/graphene composites by radio frequency (RF) sputtering with different power levels and time periods. Then, the cobalt is transformed into cobalt oxide by annealing. A longer time period of sputtering leads to higher specific capacity. Furthermore, the electrochemical stability of cobalt oxide/carbon nanotubes/graphene composites is higher than that of cobalt oxide.

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Lendzion-Bieluń, Zofia, Roman Jędrzejewski, and Walerian Arabczyk. "The effect of aluminium oxide on the reduction of cobalt oxide and thermostabillity of cobalt and cobalt oxide." Open Chemistry 9, no. 5 (October 1, 2011): 834–39. http://dx.doi.org/10.2478/s11532-011-0059-x.

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AbstractDuring precipitation and calcination at 200°C nanocrystalline Co3O4 was obtained with average size crystallites of 13 nm and a well developed specific surface area of 44 m2 g−1. A small addition of a structural promoter, e.g. Al2O3, increases the specific surface area of the cobalt oxide (54 m2 g−1) and decreases the average size of crystallites (7 nm). Al2O3 inhibits the reduction process of Co3O4 by hydrogen. Reduction of cobalt oxide with aluminium oxide addition runs by equilibrium state at all the respective temperatures. The apparent activation energy of the recrystallization process of the nanocrystalline cobalt promoted by the aluminium oxide is 85 kJ mol−1. Aluminium oxide improves the thermostability of both cobalt oxide and the cobalt obtained as a result of oxide phase reduction.

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Wai, Lee Chia, and Roszilah Ahmad. "Effect of Chromium (II, III) Oxide and Cobalt Oxide on the Colour and Fineness of Cement." Materials Science Forum 857 (May 2016): 373–76. http://dx.doi.org/10.4028/www.scientific.net/msf.857.373.

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The objective of this study is to determine the optimum portions of coloured pigments, chromium (I, II) oxide (Cr2O3) and cobalt oxide in producing coloured cement. The fineness (specific surface area - SS) of coloured cement via Blaine permeability test is also determined. The green and grey colours become darker as the percentages of chromium (II, III) oxide and cobalt oxide are increased. The chromium (II, III) oxide coloured cement become coarser as the added portions of chromium (II, III) oxide pigment is increased from 3 to 9 %. For cobalt oxide coloured cement, it becomes finer as the added portions of the cobalt oxide pigment are increased from 3 to 6 %. Results show that the optimum portions of chromium (II, III) oxide and cobalt oxide being added into the white cement in order to produce the colours at the most best is 5%. The Blaine permeability test shows that the values of the specific surface of the coloured cements comply with the Standard Specification.

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S. Amer, Mabrook, Mohamed A. Ghanem, Prabhakarn Arunachalam, Abdullah M. Al-Mayouf, and Talal A. Aljohani. "Modification Of Mesoporous Titanium Dioxide With Cobalt Oxide Electrocatalyst For Enhanced Oxygen Evolution Reaction." Advanced Materials Letters 10, no. 2 (December 19, 2018): 136–44. http://dx.doi.org/10.5185/amlett.2019.2139.

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Waris, Abdul, Misbahud Din, Asmat Ali, Shakeeb Afridi, Abdul Baset, Atta Ullah Khan, and Muhammad Ali. "Green fabrication of Co and Co3O4 nanoparticles and their biomedical applications: A review." Open Life Sciences 16, no. 1 (January 1, 2021): 14–30. http://dx.doi.org/10.1515/biol-2021-0003.

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Abstract Nanotechnology is the fabrication, characterization, and potential application of various materials at the nanoscale. Over the past few decades, nanomaterials have attracted researchers from different fields because of their high surface-to-volume ratio and other unique and remarkable properties. Cobalt and cobalt oxide nanoparticles (NPs) have various biomedical applications because of their distinctive antioxidant, antimicrobial, antifungal, anticancer, larvicidal, antileishmanial, anticholinergic, wound healing, and antidiabetic properties. In addition to biomedical applications, cobalt and cobalt oxide NPs have been widely used in lithium-ion batteries, pigments and dyes, electronic thin film, capacitors, gas sensors, heterogeneous catalysis, and for environmental remediation purposes. Different chemical and physical approaches have been used to synthesize cobalt and cobalt oxide NPs; however, these methods could be associated with eco-toxicity, cost-effectiveness, high energy, and time consumption. Recently, an eco-friendly, safe, easy, and simple method has been developed by researchers, which uses biotic resources such as plant extract, microorganisms, algae, and other biomolecules such as starch and gelatin. Such biogenic cobalt and cobalt oxide NPs offer more advantages over other physicochemically synthesized methods. In this review, we have summarized the recent literature for the understanding of green synthesis of cobalt and cobalt oxide NPs, their characterization, and various biomedical applications.

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Chansaengsri, Kasidid, Korakot Onlaor, Thutiyaporn Thiwawong, and Benchapol Tunhoo. "Effect of Annealing Temperature on Structural and Optical Properties of Cobalt Oxide Thin Films Prepared by Electrostatic Spray Deposition Technique." Key Engineering Materials 675-676 (January 2016): 229–32. http://dx.doi.org/10.4028/www.scientific.net/kem.675-676.229.

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In this work, cobalt oxide thin films were prepared by electrostatic spray deposition (ESD) technique on glass substrate. The influence of the annealing temperature on properties of cobalt oxide film was investigated. The structural, optical and morphology of cobalt oxide thin films were characterized by X-ray diffraction (XRD), Raman spectroscopy, UV-Visible spectrophotometer, scanning electron microscope, respectively. The crystalline parameters such as crystalline size of films can be obtained from XRD spectra. Phase transformation due to the different annealing temperature in cobalt oxide film has been observed. Moreover, at the higher annealing temperature, the optical band gap in cobalt oxide films were shifted to lower value due to the change in crystalline size and the defect sites in films.

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12

Kosiorek, Milena, and Mirosław Wyszkowski. "Remediation of Cobalt-Contaminated Soil Using Manure, Clay, Charcoal, Zeolite, Calcium Oxide, Main Crop (Hordeum vulgare L.), and After-Crop (Synapis alba L.)." Minerals 10, no. 5 (May 11, 2020): 429. http://dx.doi.org/10.3390/min10050429.

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This study was undertaken to determine the effects of various substances on soil contaminated with cobalt (Co) on the mass and content of cobalt in the main crop—spring barley (Hordeum vulgare L.)—and the after-crop—white mustard (Synapis alba L.). Manure, clay, charcoal, zeolite, and calcium oxide were used for phytostabilization. Cobalt was applied in the form of CoCl2 in doses of 0, 20, 40, 80, 160, and 320 mg/kg soil. Amendments in the form of manure, clay, charcoal, and zeolite were applied in an amount of 2% in relation to the weight of the soil in a pot, with calcium oxide at a dose of 1.30 g CaO/kg of soil. The highest cobalt doses resulted in a significant reduction in yield of both plants and in tolerance index for cobalt. Increasing contamination of soil with cobalt resulted in a major and significant increase in its content in plants and a reduction in cobalt translocation factor in both plants. Amendments used in phytostabilization had a significant effect on growth and development of oat and content of cobalt in plants. The strongest effect on the yield of above-ground parts was exerted by manure (both plants) and calcium oxide (white mustard), while the strongest effect on weight of roots was exerted by calcium oxide (both plants) and zeolite (white mustard). The addition of manure, zeolite and calcium oxide to soil caused an increase of the tolerance index for both plants, while the addition of clay only had a positive effect for white mustard. All substances used in phytostabilization (except zeolite) decreased cobalt content of roots, and manure and calcium oxide in above-ground parts of spring barley; manure and zeolite only in above-ground parts, and calcium oxide in both organs of white mustard. Most of them also reduced bioconcentration of cobalt in above-ground parts, calcium oxide decreased cobalt content in roots of both plants, and manure in roots of spring barley. The effect on cobalt translocation was less clear, but most substances used in phytostabilization increased the transfer of cobalt from the soil to plants. White mustard had higher ability to accumulate cobalt than spring barley.

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13

Azzi, Hajer, I. Rekkab-Hammoumraoui, L. Chérif-Aouali, and A. Choukchou-Braham. "Mesoporous Co3O4 as a New Catalyst for Allylic Oxidation of Cyclohexene." Bulletin of Chemical Reaction Engineering & Catalysis 14, no. 1 (April 15, 2019): 112. http://dx.doi.org/10.9767/bcrec.14.1.2467.112-123.

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Mesoporous cobalt oxide was investigated for the liquid phase oxidation of cyclohexene using tertiobutylhydroperoxide (TBHP) as an oxidant. The results were compared with several series of supported cobalt catalysts to study the influence of the cobalt loading and solvents on the overall conversion and selectivity. Mesoporous cobalt was synthesized through the nanocasting route using siliceous SBA-15 mesoporous material as a hard template and cobalt nitrate as the cobalt oxide precursor. Supported cobalt oxide catalysts (Co/MxOy) were synthesized by the impregnation method using two loadings (1 and 5 wt.%) and Al2O3, TiO2, and ZrO2 as supports. Samples were characterised by means: elemental analysis, X-ray powder Diffraction (XRD), BET (surface area), UV-Vis DR Spectroscopy, and MET. The results obtained showed that the cobalt oxide retains the mesoporous structure of SBA-15, and in all Co/MxOy, crystalline Co3O4 and CoO phases are observed. The mesoporous cobalt oxide is more active than the supported cobalt catalysts in the allylic oxidation of cyclohexene, with a conversion of 78 % of cyclohexene and 43.3 % selectivity toward 2-cyclohexene-1-ol. The highest activity of mesoporous cobalt oxide could be ascribed to its largest surface area. Furthermore, Co3O4 has both Lewis and Brönsted acidic sites whereas Co/MxOy has only Lewis acidic sites, which could also explain its superior catalytic activity. Moreover, mesoporous cobalt oxide was more stable than supported cobalt catalysts. Therefore, this catalyst is promising for allylic oxidation of alkenes. Copyright © 2018 BCREC Group. All rights reservedReceived: 30th March 2018; Revised: 24th September 2018; Accepted: 8th Oktober 2018; Available online: 25th January 2019; Published regularly: April 2019How to Cite: Azzi, H., Rekkab-Hammoumraoui, I., Chérif-Aouali1, L., Choukchou-Braham, A. (2019). Mesoporous Co3O4 as a New Catalyst for Allylic Oxidation of Cyclohexene. Bulletin of Chemical Reaction Engineering & Catalysis, 14 (1): 112-123 (doi:10.9767/bcrec.14.1.2467.112-123)Permalink/DOI: https://doi.org/10.9767/bcrec.14.1.2467.112-123

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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, no. 2 (May 30, 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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Qin, Bangchang, Yang Tian, Pengxiang Zhang, Zuoyin Yang, Guoxin Zhang, Zhao Cai, and Yaping Li. "A density functional theory study of the oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide." Progress in Reaction Kinetics and Mechanism 44, no. 2 (April 24, 2019): 122–31. http://dx.doi.org/10.1177/1468678319825727.

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Density functional theory calculations were employed to investigate the electrochemical oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide. Different mechanisms were applied to evaluate the oxygen reduction reaction performance of cobalt(II) oxide structures in terms of the Gibbs free energy and density of states. A variety of intermediate structures based on associative and dissociative mechanisms were constructed and optimized. As a result, we estimated the catalytic activity by calculating the free energy of the intermediates and constructing free energy diagrams, which suggested that the oxygen reduction reaction Gibbs free energy on cobalt(II) oxide (111) and (100) surfaces based on the associative mechanism is smaller than that based on the dissociative mechanism, demonstrating that the associative mechanism should be more likely to be the oxygen reduction reaction pathway. Moreover, the theoretical oxygen reduction reaction activity on the cobalt(II) oxide (111) surface was found to be higher than that on the cobalt(II) oxide (100) surface. These results shed light on the rational design of high-performance cobalt(II) oxide oxygen reduction reaction catalysts.

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Li, Cai Xia, Hai Fang Xu, Tao Feng, Na Zhang, and Qiang Li. "Synthesis and Characterization of CoO₂ Nanosheets." Advanced Materials Research 177 (December 2010): 5–8. http://dx.doi.org/10.4028/www.scientific.net/amr.177.5.

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The layered sodium cobalt oxide Na0.6CoO2 phase has been synthesized from Na2O2 and Co3O4 by solid-state reaction at 550°C for 12h with the heating rate about 2°C /min. The colloidal suspension of exfoliated, layered cobalt oxide nanosheets was prepared through the intercalation of tetrabutyl ammonium hydroxide ions (TBA) into protonated sodium cobalt oxide. The as-obtained composites were analyzed by powder X-ray diffraction (XRD). They were also cross-confirmed by a range of methods including UV/Vis spectroscopy, and Transmission Electron Microscopy (TEM). The Zeta-potential measurements clearly demonstrated the negative surface charge of cobalt oxide nanosheets.

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Hassanzadeh-Tabrizi, S. A., and E. Taheri-Nassaj. "Effect of cobalt oxide on the sintering and grain growth of Al2O3-YAG composite nanopowder." Science of Sintering 42, no. 3 (2010): 321–28. http://dx.doi.org/10.2298/sos1003321h.

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In the present study, the effect of cobalt oxide on the densification of Al2O3-YAG composite nanopowder was investigated. An amorphous nanopowder was synthesized and crystallized to Al2O3-YAG after heat-treatment via a solid-state reaction. The average particle size of heat-treated powder at 800?C was about 80 nm. Cobalt oxide improved the sintering rate of Al2O3-YAG composite nanopowders and promoted grain boundary mobility. Cobalt oxide doping increased the ratio of densification/grain growth rate. The activation energy for grain growth decreased from 590 to 485 kJ/mol by adding cobalt oxide to the composite nanopowder.

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Li, Lin Bo, Juan Qin Xue, Tao Hong, Jun Yang, and Xing Wang. "Separation of Cobalt from Zinc Sulfate Solution by Novel Oxidant." Materials Science Forum 695 (July 2011): 145–48. http://dx.doi.org/10.4028/www.scientific.net/msf.695.145.

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The separation of cobalt from zinc sulfate solutions by oxidation-precipitation process using peroxy-monosulfuric acid as oxidant has been presented according to the technological conditions of removal of cobalt from zinc electrolyte. After investigating the important parameters governing the separation of cobalt and their effect on the separation process, the optimal parameters of oxidation precipitation of cobalt were determined, the oxidation precipitation percent of cobalt was up to 90% under the conditions. The XRD analysis results of precipitates demonstrated that the precipitate was cobalt hydroxide oxide (CoOOH) in pure cobalt system while the precipitates were cobaltosic oxide (Co3O4) and basic zinc sulfate (ZnSO4(OH)6.H2O) in zinc-cobalt system.

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Prasetyo, Imam, Nur Indah Fajar Mukti, and Teguh Ariyanto. "Ethylene Adsorption Using Cobalt Oxide-Loaded Polymer-Derived Nanoporous Carbon and Its Application to Extend Shelf Life of Fruit." Molecules 24, no. 8 (April 17, 2019): 1507. http://dx.doi.org/10.3390/molecules24081507.

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Suppressing the amount of ethylene during storage has been of interest as a method to enhance shelf life of fruit. In this work, ethylene removal by adsorption using cobalt oxide-impregnated nanoporous carbon has been studied. Nanoporous carbon with a high surface area up to 2400 m2 g−1 was prepared by carbonization process biomass and synthetic polymer at 850 °C. Dispersion of cobalt oxide on porous carbon surface was carried out by an incipient wetness procedure followed by calcination process at 200 °C. Ethylene adsorption test was performed using a volumetric method in an ultrahigh vacuum rig constructed by Swagelok VCR® fittings. The results showed that the cobalt oxide/carbon system had significant ethylene adsorption capacity. Ethylene uptake increases with the increasing cobalt oxide loading on the carbon. The highest ethylene capacity of 16 mol kg−1 adsorbent was obtained by using 30 wt.% (weight percentage) of cobalt oxide dispersed in polymer-derived carbon. In closed storage, the ratio of 15 g adsorbent/kg fruit may extend the storage life up to 12 d, higher than that without adsorbent (3 d). Therefore, the results demonstrate the great potential use of cobalt oxide-impregnated nanoporous carbon as an adsorbent for ethylene removal during storage of fruit.

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Blin, Jean-Luc, Laure Michelin, Bénédicte Lebeau, Anton Naydenov, Ralitsa Velinova, Hristo Kolev, Pierrick Gaudin, et al. "Co–Ce Oxides Supported on SBA-15 for VOCs Oxidation." Catalysts 11, no. 3 (March 11, 2021): 366. http://dx.doi.org/10.3390/catal11030366.

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Reported here are new data on the structural and catalytic properties of a series of mono-component cobalt and bi-component Co–Ce catalysts supported on SBA-15 (Santa Barbara Amorphous-15)). The catalysts performance has been evaluated by tests on combustion of methane, propane, and n-hexane. It was established that the preparation of the Co–Ce catalysts by the ‘two-solvent’ technique does not significantly change the mesoporous structure, however, its pores are clogging with the Co and Ce guest species. Cobalt and cerium are uniformly distributed and preferentially fill up the channels of SBA-15, but oxide agglomerates located on the surface are observed as well. The highest activity of the mono-component cobalt sample is explained by its higher reducibility as a result of lower interaction of the cobalt oxide with the SBA-15. The fine dispersion of cobalt and cerium oxide and their strong interaction in the channels of the SBA-15 molecular sieve, leads to the formation of difficult-to-reduce oxide phases and, consequently, to lower catalytic activity compared to monocomponent cobalt oxide catalyst. The synthesised mesoporous structure can prevent the agglomeration of the oxide particles, thus leading to the successful development of a new and stable catalyst for decreasing greenhouse gas emissions.

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Tu, Nguyen Van. "SYNTHESIS AND ELECTROCHEMICAL PROPERTIES OF MESOPOROUS CARBON SUPPORTED WELL–DISPERSED COBALT OXIDES NANOPARTICLES." Vietnam Journal of Science and Technology 55, no. 1B (March 23, 2018): 230. http://dx.doi.org/10.15625/2525-2518/55/1b/12114.

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In this article, well–dispersed cobalt oxide nanoparticles supported on mesoporous carbon (CMK–3) have been successfully synthesized. The composites were characterized by field emission scanning electron microscopy, transmission electron microscopy, X–ray diffraction and nitrogen adsorption–desorption analysis. The results have confirmed that, at a cobalt loading of 15 wt%, the composites have not only retained mesoporous structure of the support but also shown a good control of dispersed cobalt oxide nanoparticles with size of ~4 nm. The electrochemical property tests for the synthesized samples have shown significant improvement compared to the blank carbon (CMK–3) without cobalt oxide incorporation.

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Wu, Yingsi, Qianqian Shi, Yuhang Li, Zhuangchai Lai, Hao Yu, Hongjuan Wang, and Feng Peng. "Nitrogen-doped graphene-supported cobalt carbonitride@oxide core–shell nanoparticles as a non-noble metal electrocatalyst for an oxygen reduction reaction." Journal of Materials Chemistry A 3, no. 3 (2015): 1142–51. http://dx.doi.org/10.1039/c4ta03850a.

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Cobalt carbonitride@oxide core–shell nanoparticles supported on nitrogen-doped graphene present excellent activity in ORR, benefiting from the electronic modification of cobalt oxide by carbonitride from within.

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Chopra, Nitin, Yuan Li, and Kuldeep Kumar. "Cobalt oxide-tungsten oxide nanowire heterostructures: Fabrication and characterization." MRS Proceedings 1675 (2014): 191–96. http://dx.doi.org/10.1557/opl.2014.863.

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ABSTRACTNanowire heterostructures comprised of cobalt oxide and tungsten oxide were fabricated in a core/shell configuration. This was achieved by sputter coating tungsten oxide shells on standing cobalt oxide nanowires on a substrate. To ensure the polycrystallinity of tungsten oxide shell, the nanowire heterostructures were subjected to post-sputtering annealing process. The cobalt oxide nanowires for this study were grown employing a thermal method via vapor-solid growth mechanism. The crystal structures, morphologies, dimensions, and phases at various growth stages of nanowire heterostructures were studied using high resolution electron microscopy, energy dispersive spectroscopy, and X-ray diffraction methods. The interfaces of these nanowire heterostructures were also studied and showed variation in the lattice spacing across the heterostructure diameter. Results indicated that the cobalt oxide nanowires survived multiple processing steps and resulted in stable heterostructure configurations. The investigation shows, for the first time, a dry processing route for the formation of such novel nanowire heterostructures.

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Wang, Long Fan, Zhi Jian Peng, Ming Lei, and Xiu Li Fu. "Solvothermal Growth of Cobalt Oxide Hexagon Nanodiscs." Key Engineering Materials 512-515 (June 2012): 166–69. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.166.

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In this work, cobalt oxide nanodiscs were successfully fabricated through a simple solvothermal synthesis method. The obtained cobalt hydroxide nanodiscs are of single-crystalline hexagonal structure with well-defed nanodiscs were found to have very weak magnetic properties, much weaker than its bulk cobalt oxide counterparts, which might find interesting application in special electromagnetism devices.

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Moradpoor, Hedaiat, Mohsen Safaei, Farzad Rezaei, Amin Golshah, Ladan Jamshidy, Reza Hatam, and Rawand S. Abdullah. "Optimisation of Cobalt Oxide Nanoparticles Synthesis as Bactericidal Agents." Open Access Macedonian Journal of Medical Sciences 7, no. 17 (August 30, 2019): 2757–62. http://dx.doi.org/10.3889/oamjms.2019.747.

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AIM: With the increased bacterial resistance and the resulting problems in recent years, it seems necessary to find new biocompatible compounds to confront this problem. This research was conducted to optimise the synthesis of cobalt oxide nanoparticles with the highest antibacterial activity. METHODS: In the present study, 9 experiments were designed using the Taguchi method. The effect of three factors of cobalt nitrate, KOH and the stirring time in the synthesis of cobalt oxide nanoparticles with the highest antibacterial activity was investigated. The bactericidal effect of synthesised nanoparticles was evaluated using the colony-forming unit (CFU) and disk diffusion methods. The characteristics of nanoparticles were studied using the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and the scanning electron microscopy (SEM). RESULTS: The results indicated that all three evaluated factors were effective on the antibacterial properties of the synthesised nanoparticles. The best antibacterial activity of cobalt oxide nanoparticles was observed in experiment 9 (cobalt nitrate 0.6 M, KOH 2M and stirring time 60 min). The study of nanoparticles synthesised by FTIR, XRD, and SEM confirmed the formation of cobalt oxide nanoparticles with size (24 nm) and a proper structure (spinel structure). CONCLUSION: Due to the optimal antibacterial properties of the synthesised cobalt oxide nanoparticles, they can be used in the fabrication of dental and medical equipment with antibacterial properties.

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Arzumanova, A. V., and A. V. Starunov. "Effect of Electrolysis Modes on Physico-Mechanical Properties of Composite Coatings Based on Nickel." Materials Science Forum 945 (February 2019): 647–52. http://dx.doi.org/10.4028/www.scientific.net/msf.945.647.

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The receiving method and some properties of the composite nickel containing galvanic coating on base nickel-cobalt-oxide silicon-carbide silicon system were discussed. Chloride electrolyte for the application of the composite electroplating coating with firmness to wear and corrosion properties of nickel-cobalt-oxide silicon-carbide silicon system was elaborated. Influence of electrolysis and electrolyte composition on physico-mechanical properties (firmness to wear, corrosion resistance, hardness, internal tensions, porosity, adhesion) of the composite electrolytic coating of nickel-cobalt-silicon oxide system, electroplated from chloride electrolyte, and on the properties of electrolyte (diffusing ability, output current draught) were investigated. The possibility of using for composite electroplating of nickel-cobalt-silicon oxide-carbide silicon system as a firmness to wear coating in instead of chrome was showed.

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Alex John Thangapaul, A., V. Sherly Arpuda Kiruba, R. Nivea, T. Viji, K. Thiyagarajan, Alphonse Dhayal Raj, and S. Vasanth Kumar. "Nanorods of Cobalt Oxide: Study on its Morphology with Varied Sonication Time." Advanced Materials Research 678 (March 2013): 203–6. http://dx.doi.org/10.4028/www.scientific.net/amr.678.203.

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Nanomaterials research has become a major attraction in the field of advanced materials research in the area of Physics, Chemistry, and Materials Science. Biocompatible and chemically stable magnetic metal oxide nanoparticles have biomedical applications that includes drug delivery, cell and DNA separation, gene cloning, magnetic resonance imaging (MRI). This research is aimed at the fabrication of magnetic cobalt oxide nanoparticles using a safe, cost effective, and easy to handle technique that is capable of producing nanoparticles free of any contamination. Nanostructured Cobalt oxide powder was prepared by sonication method using ultrasonicator. Effect of sonication for different time intervals, on the morphology of cobalt oxide nanostructures was extensively studied. The morphology of the nanorods were very much affected by the sonication time, it was found that with an increase in sonication time, the length of the nanorods seem to considerably increase at the same time an agglomeration effect comes in to action and the rods form bundle like structures. These cobalt oxide nanorods were characterized using X-ray Diffraction characterization (XRD) and it revealed a cubic structure. Weight percentage of cobalt oxide was confirmed by thermo gravimetric analysis (TGA).

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Diao, Yong Fa, Jian Dong Ding, Wan Xuan Yu, Yue Zou, and Wei Hui Hao. "Application of Activated Carbon Fiber Coated with Cobalt Oxide in Mercury Removal from Simulated Flue Gas." Advanced Materials Research 356-360 (October 2011): 547–53. http://dx.doi.org/10.4028/www.scientific.net/amr.356-360.547.

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In this paper, cobalt oxide was deposited on the surface of Activated Carbon Fiber (ACF) by adsorption and was then sintered. The effects of cobalt oxide on the properties of ACF were studied by XPS, FTIR, and XRD methods. Mercury removal performance was also investigated. 5% cobalt was well dispersed on the surface of ACF, and a variety of oxygen-containing groups had been enhanced. The chemical functional groups on the surface of ACF were changed to strengthen the adsorption and catalytic oxidation of ACF to the element mercury (Hg0). The measurement results showed that ACF coated with cobalt oxide had higher adsorption properties.

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Girardi, Leonardo, Luca Bardini, Niccolò Michieli, Boris Kalinic, Chiara Maurizio, Gian Rizzi, and Giovanni Mattei. "Co3O4 Nanopetals on Si as Photoanodes for the Oxidation of Organics." Surfaces 2, no. 1 (January 11, 2019): 41–53. http://dx.doi.org/10.3390/surfaces2010004.

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Cobalt oxide nanopetals were grown on silicon electrodes by heat-treating metallic cobalt films deposited by DC magnetron sputtering. We show that cobalt oxide, with this peculiar nanostructure, is active towards the photo-electrochemical oxidation of water as well as of organic molecules, and that its electrochemical properties are directly linked to the structure of its surface. The formation of Co3O4 nanopetals, induced by oxidizing annealing at 300 °C, considerably improves the performance of the material with respect to simple cobalt oxide films. Photocurrent measurements and electrochemical impedance are used to explain the behavior of the different structures and to highlight their potential application in water remediation technologies.

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LIU, LIHONG. "SINGLE-STEP SYNTHESIS OF COBALT-OXIDE SHELLED NANOCARBONS." International Journal of Nanoscience 04, no. 04 (August 2005): 591–98. http://dx.doi.org/10.1142/s0219581x05003255.

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In this paper, we report a simple solid-state method for fabricating cobalt-oxide–carbon core-shell nanostructures. With this technique, various forms of nanocarbons such as nanotubes, polyhedrons and onions can be generated via pyrolyzing cobalt–complex xerogels at 150 ~ 340°C. The thus-formed nanocarbons can be protected by cobalt-oxide matrix up to 1000°C in air atmosphere. Cobalt-oxide shelled or unshelled nanocarbons can be controlled by choosing a suitable complexing agent for the xerogel precursors. In particular, glycine has been proven to be a good complexing agent for low-temperature formation of unshelled nanocarbons and high-temperature generation of shelled nanocarbons.

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Yang, Fan, Xinghao Zhou, Noah T. Plymale, Ke Sun, and Nathan S. Lewis. "Evaluation of sputtered nickel oxide, cobalt oxide and nickel–cobalt oxide on n-type silicon photoanodes for solar-driven O2(g) evolution from water." Journal of Materials Chemistry A 8, no. 28 (2020): 13955–63. http://dx.doi.org/10.1039/d0ta03725g.

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Thin films of nickel oxide (NiO_x), cobalt oxide (CoO_x) and nickel–cobalt oxide (NiCoO_x) produced integrated, protected Si (111) photoanodes integrated, protected Si photoanodes that did not require deposition of a separate heterogeneous electrocatalyst for water oxidation.

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Prasetyo, Imam, Nur Indah Fajar Mukti, Moh Fahrurrozi, and Teguh Ariyanto. "Removing Ethylene by Adsorption using Cobalt Oxide-Loaded Nanoporous Carbon." ASEAN Journal of Chemical Engineering 18, no. 1 (October 29, 2018): 9. http://dx.doi.org/10.22146/ajche.49542.

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Ethylene is naturally generated by climacteric fruits and can promote the ripening process faster. For effective long-distance transport and subsequent storage, removing ethylene from the storage environment has been of interest to suppress its undesirable effect. In this study, ethylene removal by an adsorptive method using cobalt-loaded nanoporous carbon is studied. Cobalt oxide-loaded carbon was prepared by incipient wetness method followed by calcination process at 200 °C under inert flow. Ethylene adsorption test was performed at 20, 30, and 40 °C using a static volumetric test. The results showed that cobalt oxide/carbon system has significant ethylene adsorption capacity up to 3.5 times higher compared to blank carbon. A higher temperature adsorption is more favorable for this chemisorption process. Ethylene uptake increases from 100 to 150 mL g-1adsorbent STP by increasing cobalt oxide loading on carbon from 10 to 30 wt.% Co. The highest uptake capacity of 6 mmol ethylene per gram adsorbent was obtained using 30 wt.% cobalt oxide. Therefore, ethylene adsorption by cobalt-loaded nanoporous carbon may represent a potential method in ethylene removal and it could serve as a basis for development of ethylene scavenging material.

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Akbari Moayyer, Hamid, and Abolghasem Ataie. "Investigation on Phase Evolution in the Processing of Nano-Crystalline Cobalt Ferrite by Solid-State Reaction Route." Advanced Materials Research 829 (November 2013): 767–71. http://dx.doi.org/10.4028/www.scientific.net/amr.829.767.

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Cobalt ferrite nanocrystalline powder was synthesized from the powder mixture of cobalt carbonate and iron oxide by mixed oxide ceramic method. The effects of temperature of calcination as well as molar ratio of CoCO3/Fe2O3on the phase structure, morphology and magnetic properties of the products were studied using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and vibrating sample magnetometer (VSM) techniques, respectively. The samples calcined at 800 and 900 C consisted of cobalt ferrite, iron oxide and cobalt oxide. In the sample calcined at 1000 C, the reaction was completed and single phase CoFe2O4with a mean crystallite and particle sizes of 49 and 300 nm, respectively was obtained. The above sample showed hard magnetic behavior with a coercivity of 337 Oe, saturation magnetization of 76 emu/g and remanence of 19 emu/g.

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Ambika, S., S. Gopinath, K. Sivakumar, and K. Saravanan. "Spinel-Type Cobalt Oxide Nanoparticles: Synthesis, Characterization and Antibacterial Properties." Advanced Science, Engineering and Medicine 12, no. 7 (July 1, 2020): 859–63. http://dx.doi.org/10.1166/asem.2020.2623.

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A series of cobalt oxide nanoparticles (sample A (300 °C), sample B (400 °C) and sample C (500 °C)) are synthesized in a starch medium by the hydrothermal method followed by annealing. The structural, morphological, and magnetic, of these cobalt oxide nanoparticles, become characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) correspondingly. Furthermore, it can be seen that the increase in the synthesis temperature results in a substantial increase in the average particle size. The impact of synthesis temperature in relation to morphology (size and shape) and magnetic properties of cobalt oxide nanoparticles has been investigated. Besides, the antibacterial and catalytic activity of these nanoparticles are examined. A systematic analysis is presented on the influence of parameters of synthesis on the formation and structural properties of cobalt oxide nanoparticles. We expect in which this topic will give many valuable ideas for the metal oxide nanomaterials development, synthesis, as well as applications.

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Kumar, Rahul, Ankur Soam, and Veena Sahajwalla. "Carbon coated cobalt oxide (CC-CO3O4) as electrode material for supercapacitor applications." Materials Advances 2, no. 9 (2021): 2918–23. http://dx.doi.org/10.1039/d1ma00120e.

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Carbon coated cobalt oxide (CC-Co₃O₄) was synthesized using sucrose and cobalt oxide. CC-Co₃O₄ can be used as electrode material for supercapacitor applications

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36

Eliseeva, E. A., S. L. Berezina, I. G. Gorichev, L. E. Slynko, and V. N. Goryacheva. "The Initial Surface Structure of Co3O4 as a Factor of Influence on Kinetic Features of the Dissolution of the Solid Phase." Herald of the Bauman Moscow State Technical University. Series Natural Sciences, no. 4 (91) (August 2020): 138–44. http://dx.doi.org/10.18698/1812-3368-2020-4-138-144.

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Due to the depletion of natural reserves of cobalt-containing ores, it is urgent to optimize the processes of cobalt replenishment, based on the leaching of its compounds, processing of industrial waste, regeneration of cobalt compounds from catalysts. The kinetic characteristics of the dissolution of metal oxides are influenced by the initial state of their surface structure, which requires the accumulation of experimental material and individual targeted studies. The paper presents the results of an experimental study of the surface structure of industrial Co3O4 cobalt oxide samples. The studies were carried out by electron microscopy and X-ray phase analysis and revealed the size and shape of the Co3O4 particles and the nature of their surface distribution. The correspondence of experimental and theoretical data has been established, Co3O4 cobalt oxide has been identified as an α-form of the cubic crystal system. The data obtained are of interest in the study of the effect of the surface characteristics of the solid phase of Co3O4 cobalt oxide on the dissolution kinetics under the chemical and electrochemical influence

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Jin, Chunming, Sudhakar Nori, Wei Wei, Ravi Aggarwal, Dhananjay Kumar, and Roger J. Narayan. "Pulsed Laser Deposition of Nanoporous Cobalt Thin Films." Journal of Nanoscience and Nanotechnology 8, no. 11 (November 1, 2008): 6043–47. http://dx.doi.org/10.1166/jnn.2008.483.

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Nanoporous cobalt thin films were deposited on anodized aluminum oxide (AAO) membranes at room temperature using pulsed laser deposition. Scanning electron microscopy demonstrated that the nanoporous cobalt thin films retained the monodisperse pore size and high porosity of the anodized aluminum oxide substrates. Temperature- and field-dependent magnetic data obtained between 10 K and 350 K showed large hysteresis behavior in these materials. The increase of coercivity values was larger for nanoporous cobalt thin films than for multilayered cobalt/alumina thin films. The average diameter of the cobalt nanograins in the nanoporous cobalt thin films was estimated to be ∼5 nm for blocking temperatures near room temperature. These results suggest that pulsed laser deposition may be used to fabricate nanoporous magnetic materials with unusual properties for biosensing, drug delivery, data storage, and other technological applications.

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Sharma, Aditya, D. K. Sharma, Kapil Sharma, and Vipin Kumar. "Structural and Infrared Spectroscopy Study of Chemically Synthesized Sn_1-xCo_xO₂(0.00 ≤ x ≤ 0.05) Nanoparticles." Advanced Materials Research 585 (November 2012): 179–82. http://dx.doi.org/10.4028/www.scientific.net/amr.585.179.

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In this work, an effective and economic way of transition metal doping in tin oxide nanoparticles is presented. The x-ray diffraction (XRD) measurements confirmed that the SnO2 nanoparticles are of single phase with rutile structure. Transmission electron microscopy (TEM) micrographs show that nanoparticles exhibit spherical shape with size of ~4 nm. To check the incorporation of cobalt and its chemical bonding with oxygen, systematic FTIR measurements were performed. The stretching-vibration mode (A2u) of Sn-O and deformation-vibration mode (Eu) of O-Sn-O were found to be broadened and shifted towards the higher wave numbers in case of cobalt doped samples. The Co-O/O-Co-O modes of the stable phase of cobalt oxide (Co2O3) were not detected in any doped samples. The results indicate that cobalt is present in the tin oxide lattice and do not form any metallic clusters or its oxide phases.

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39

Sokolov, Ilya E., Valery V. Fomichev, Ruslan M. Zakalyukin, Elena V. Kopylova, Andrey S. Kumskov, Rais N. Mozhchil, and Andrey M. Ionov. "SYNTHESIS OF NANOSIZED ZIRCONIUM DIOXIDE, COBALT OXIDE AND RELATED PHASES IN SUPERCRITICAL CO2 FLUID." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 64, no. 5 (May 13, 2021): 35–43. http://dx.doi.org/10.6060/ivkkt.20216405.6060.

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This study is devoted to obtaining nanoscale zirconium dioxide, cobalt oxide and related phases by SAS method in supercritical carbon dioxide. The synthesized compounds were characterized by a complex of physico-chemical analytical methods: infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy. The experimental parameters for obtaining the nanoparticles were: pressure 10 MPa, temperature 40 °C, carbon dioxide supply rate 35 g/min, the initial solution supply rate 0.5 ml/min. Individual phases containing zirconium and cobalt, and also samples with zirconium to cobalt molar ratios 3:1, 2:1, 1:1, 2:1 and 1:3 were obtained. The use of zirconium and cobalt acetylacetonates as initial components leads to formation of stable products – nanoparticles of acetates of the corresponding metals in the X-ray amorphous state. When heated to 340-350 °C, the destruction of organometallic complexes to oxides occurs with formation of a continuous series of X-ray amorphous solid solutions in the ZrO2-CoO system. At temperatures above 600 °C, the phases crystallize with the decomposition of solid solutions into ZrO2 and Co3O4. When temperature is above 900 °C, further oxidation of cobalt occurs. Thus, cobalt oxide oxidation into Co3O4 proceeds in two steps, at 600 and 900 °C. For samples of zirconium dioxide with cobalt oxide admixture at a temperature of 700 °C stabilization of the cubic modification is observed which is probably due to the entry of cobalt into the cubic structure of zirconium oxide, which prevents transition to tetragonal and monoclinic modifications.

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Aguilera-del-Toro, R. H., F. Aguilera-Granja, A. Vega, and L. C. Balbás. "Structure, fragmentation patterns, and magnetic properties of small cobalt oxide clusters." Phys. Chem. Chem. Phys. 16, no. 39 (2014): 21732–41. http://dx.doi.org/10.1039/c4cp03370a.

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Wolf, Moritz, Stephen J. Roberts, Wijnand Marquart, Ezra J. Olivier, Niels T. J. Luchters, Emma K. Gibson, C. Richard A. Catlow, Jan H. Neethling, Nico Fischer, and Michael Claeys. "Synthesis, characterisation and water–gas shift activity of nano-particulate mixed-metal (Al, Ti) cobalt oxides." Dalton Transactions 48, no. 36 (2019): 13858–68. http://dx.doi.org/10.1039/c9dt01634a.

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42

Al-Fakeh, Maged S., and Roaa O. Alsaedi. "Synthesis, Characterization, and Antimicrobial Activity of CoO Nanoparticles from a Co (II) Complex Derived from Polyvinyl Alcohol and Aminobenzoic Acid Derivative." Scientific World Journal 2021 (April 27, 2021): 1–11. http://dx.doi.org/10.1155/2021/6625216.

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Cobalt oxide nanoparticles (CoO NPs) were synthesized by the calcination method from the Co (II) complex which has the formula [Co(PVA)(P-ABA)(H2O)3], PVA = polyvinyl alcohol, and P-ABA = para-aminobenzoic acid. The calcination temperature was 550°C, and the products were characterized by element analysis, thermal analyses (TGA and DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-Vis spectra, and scanning electron microscopy (SEM) techniques. The kinetic and thermodynamic parameters (∆H ∗ , ∆G ∗ , and ∆S ∗ ) for the cobalt (II) complex are calculated. The charges been carried by the atoms cause dipole moment 10.53 and 3.84 debye and total energy 11.04 × 102 and 24.80 × 102k Cal mol−1 for the Co (II) complex and cobalt oxide, respectively. X-ray diffraction confirmed that the resulting oxide was pure single-crystalline CoO nanoparticles. Scanning electron microscopy indicating that the crystallite size of cobalt oxide nanocrystals was in the range of 36–54 nm. Finally, the antimicrobial activity of cobalt oxide nanoparticles was evaluated using four bacterial strains and one fungal strain. Two strains of Gram-positive cocci (Staphylococcus aureus and Enterococcus faecalis), two strains of Gram-negative bacilli (Escherichia coli and Pseudomonas aeruginosa), and one strain of yeast such as fungi (Candida albicans) were used in this study.

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Xu, Jing Li, Ping Liu, Yang Lu, Jia Chang Zhao, Ji Cheng Feng, Yi Wen Song, and Bo He Jin Tang. "Ordered Mesoporous Carbon/Cobalt Oxide Composites as the Electrode Materials for Supercapacitor." Advanced Materials Research 239-242 (May 2011): 1026–29. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.1026.

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A series of ordered mesoporous carbon/cobalt oxide composites as electrode materials for supercapacitor were prepared via incipient wetness impregnation method. The results show that the structure and electrochemical properties of the composites depend mainly on the cobalt oxide loading amount in the ordered mesoporous carbon. The optimum loading amount of cobalt oxide is found to be 30 wt.%, and the composite derived from which exhibits 283.52 F/g of specific capacitance at the scan rate of 5 mV/s. The specific capacitances of which are higher than that of OMC and pure Co3O4 at every given scan rate, showing good synergetic effect.

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Tran, Tri Truong Trong, My Thi Mai Nguyen, Hanh Ngoc Nguyen, and Thao Huu Vo. "Removal of nonyl phenol ethoxylates in water by catalytic ozonation in presence of silica supported - cobalt nanoparticles." Science and Technology Development Journal 19, no. 3 (September 30, 2016): 50–59. http://dx.doi.org/10.32508/stdj.v19i3.583.

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The catalytic ozonation of nonionic surfactant nonylphenolethoxylate (NPE) as pollutant in wastewater and its degradation in the presence of silica-supported Cobalt oxide nanoparticles was studied. Characterization of silica supported- cobalt oxide was made using XRD patterns and SEM profiles. The influence of pH, initial NPE concentration, ozonation time and catalyst contents in ozonation process was also investigated. Results show that NPE removals by using silica supported-cobalt oxide catalytic systems are higher than that of using single ozonation. About 99% NPE were removed within 10 min at 30oC. Furthermore, in this condition more than 50% of total carbon of NPE was mineralized.

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Mukti, Nur Indah Fajar, Imam Prasetyo, and Aswati Mindaryani. "PREPARASI KARBON TEREMBAN OKSIDA COBALT DARI LIMBAH KULIT MANGGIS SEBAGAI ADSORBEN PENJERAP ETILEN UNTUK PENGAWETAN BUAH." Reaktor 15, no. 3 (September 24, 2015): 165. http://dx.doi.org/10.14710/reaktor.15.3.165-174.

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Ethylene is a compound produced naturally by fruit that can accelerate the maturity of the fruit. Controlling ethylene gas as a product of metabolism of fruit during storage will prolong the shelf life of the fruit. Controlling ethylene gas is carried out by adsorption process using carbon-impregnated cobalt oxide. In this study, carbon as a support made by pyrolysis of extraction waste of mangosteen peel at a temperature of 850°C for 15 minutes. Furthermore, the process of impregnating of cobalt oxide into the carbon pore network was carried out by using the incipient wetness impregnation method by adding a cobalt salt solution into the carbon pore network, followed by heating at a temperature of 110oC for 8 hours and calcination at a temperature of 200oC for 6 hours. Ethylene adsorption test performed at 30°C using a static volumetric test. While Cavendish banana fruit preservation process was carried out at ambient temperature (20-32oC) by observing the changing of skin color from day to day. Adsorption test results showed that the ethylene uptake increased with the increasing of the composition of cobalt oxide on the carbon surface. The highest ethylene uptake of 6.094 mmol/(gram of adsorbent) was obtained from adsorption of ethylene using carbon-impregnated 30% cobalt oxide. Fruit preservation process indicated that the increasing of amount of adsorbent can improve the shelf life of bananas Cavendish. The highest result was obtained from the addition of 15 grams of carbon-impregnated cobalt oxide and silica gel that can extend the shelf life of bananas Cavendish for 15 days. Keywords: adsorption; carbon; cobalt oxide; ethylene; impregnation Abstrak Etilen merupakan senyawa yang dihasilkan secara alami oleh buah yang dapat mempercepat kematangan pada buah. Pengontrolan gas etilen sebagai produk metabolisme buah selama penyimpanan akan memperpanjang masa simpan buah tersebut. Pengontrolan gas etilen dilakukan dengan proses adsorpsi menggunakan karbon teremban oksida cobalt. Pada penelitian ini, karbon sebagai pengemban dibuat dari pirolisis limbah kulit manggis sisa ekstraksi pada suhu 850oC selama 15 menit. Selanjutnya, proses pengembanan oksida cobalt pada permukaan karbon dibuat melalui proses impregnasi dengan incipient wetness method yang dilakukan dengan menambahkan larutan garam cobalt ke dalam jaringan pori karbon yang dilanjutkan dengan pemanasan pada suhu 110oC selama 8 jam dan kalsinasi pada suhu 200oC selama 6 jam. Uji adsorpsi etilen dilakukan pada suhu 30oC menggunakan alat uji static volumetric. Sedangkan proses pengawetan buah pisang Cavendish dilakukan pada suhu lingkungan (20 – 32oC) dengan mengamati perubahan warna kulitnya dari hari ke hari. Hasil uji adsorpsi menunjukkan bahwa semakin banyak komposisi oksida cobalt pada permukaan karbon akan meningkatkan kapasitas penjerapan terhadap etilen. Hasil tertinggi sebesar 6,094 mmol/(gram adsorben) diperoleh dari adsorpsi etilen menggunakan karbon teremban 30% oksida cobalt. Dari proses pengawetan buah menunjukkan bahwa jumlah karbon teremban oksida cobalt yang semakin meningkat dapat meningkatkan umur simpan dari buah pisang Cavendish. Hasil tertinggi diperoleh dari penambahan 15 gram karbon teremban cobalt dan silica gel dapat memperpanjang umur simpan buah pisang Cavendish selama 15 hari. Kata kunci: adsorpsi; karbon; oksida cobalt; etilen; impregnasi

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46

Kesavan, V., D. Dhar, Y. Koltypin, N. Perkas, O. Palchik, A. Gedanken, and S. Chandrasekaran. "Nanostructured amorphous metals, alloys, and metal oxides as new catalysts for oxidation." Pure and Applied Chemistry 73, no. 1 (January 1, 2001): 85–91. http://dx.doi.org/10.1351/pac200173010085.

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The oxidation of cyclohexane with molecular oxygen in the presence of isobutyraldehyde catalyzed by nanostructured iron and cobalt oxides and iron oxide supported on titania has been studied. Nanostructured cobalt oxide on MCM-41 is found to be efficient for catalytic aerobic epoxidation of olefins.

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Aitugan, A. N., S. K. Tanirbergenova, Ye Tileuberdi, and D. Tugelbayeva. "MODIFIED COBALT CATALYSTS FOR HYDROGENATION OF HYDROCARBONS." Горение и Плазмохимия 18, no. 3 (September 29, 2020): 156–61. http://dx.doi.org/10.18321/cpc364.

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This work is devoted to the study of the influence of aluminum oxide content on the activity of cobalt catalysts in the reaction of selective hydrogenation of acetylene to ethylene. Cobalt catalysts modified with aluminum oxide having size between 50 to 500 nm were synthesized. Chemical contents and structure of carrier were investigated. The catalytic activity of 5 % Со /clay and 5% Co/SiAl catalysts at acetylene hydrogenation was studied in the temperature range 100-180 , with a ratio of 1:2 of acetylene and hydrogen. The ethylene yield is 87.8 % in modifying the cobalt catalyst with aluminum oxide, whereas with the same process parameters, the ethylene yield is 72 %. 5 % Cobalt catalysts modified with 1.5 % aluminum oxides are more active in hydrogenation acetylene process than 5 % Со /clay 450 ℃ catalyst.

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Wang, Zhongzhu, Hong Bi, Peihong Wang, Min Wang, Zhiwei Liu, Lei shen, and Xiansong Liu. "Magnetic and microwave absorption properties of self-assemblies composed of core–shell cobalt–cobalt oxide nanocrystals." Physical Chemistry Chemical Physics 17, no. 5 (2015): 3796–801. http://dx.doi.org/10.1039/c4cp04985c.

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Villalobos, Javier, Diego González-Flores, Katharina Klingan, Petko Chernev, Paul Kubella, Roberto Urcuyo, Chiara Pasquini, et al. "Structural and functional role of anions in electrochemical water oxidation probed by arsenate incorporation into cobalt-oxide materials." Physical Chemistry Chemical Physics 21, no. 23 (2019): 12485–93. http://dx.doi.org/10.1039/c9cp01754b.

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Chee, Kai Ling, Noor Asmawati Mohd Zabidi, and Mohan Sinnathambi Chandra. "Synthesis of Cobalt Nano Particles on Silica Support Using the Strong Electrostatic Adsorption (SEA) Method." Defect and Diffusion Forum 312-315 (April 2011): 370–75. http://dx.doi.org/10.4028/www.scientific.net/ddf.312-315.370.

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Supported cobalt is one of the common catalysts used in Fischer-Tropsch synthesis (FTS). Strong electrostatic adsorption (SEA) was employed to synthesize cobalt nano particles supported on silica. Cobalt nitrate was used as the catalyst precursor and non-porous silica spheres, which were synthesized using the modified Stöber method, were used as a catalyst support. Point of zero charge (PZC) for silica was determined using equilibrium pH at high oxide loading (EpHL) method. The optimum pH was determined by measuring cobalt uptake versus pH. High cobalt uptake at basic pH and low cobalt uptake at acidic pH indicates electrostatic interaction between the cobalt complexes in the precursor solution and the hydroxyl group on the support’s surface. Catalysts prepared at optimum pH were characterized using TPR, XPS and TEM. TPR shows reduction peak at high temperature (587°C) indicating strong interaction between cobalt and silica support. XPS shows presence of Co2+ species on the surface. TEM images of the Co/SiO2 at 5 wt% and 10 wt% cobalt loadings show fairly well-dispersed cobalt oxide nano particles on the spherical silica support with narrow particle size distribution. The findings suggest that SEA was deemed a suitable method to prepare supported cobalt catalysts.

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Journal articles on the topic 'Oxyde de cobalt'

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