Journal articles: 'Cobalt oxide'

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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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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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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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Hacınecipoğlu, Ayşe V., Metin Gençten, Melih B. Arvas, and Yucel Sahin. "Preparation of Spinel Form Co₃O₄ and CoO₂ Thin Film at Low Temperature by Electrochemical Method as a Thin Film Oxide Layer." ECS Journal of Solid State Science and Technology 11, no. 8 (August 1, 2022): 081014. http://dx.doi.org/10.1149/2162-8777/ac8a6f.

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In this work, thin films of cobalt oxides (CoO2, Co3O4) were prepared using the electrochemical method on the pencil graphite and indium tin oxide surfaces. The substrate effect in the production of both oxides has been studied in detail. While Co3O4 accumulates on the pencil graphite’s surface, CoO2 formation was observed on the indium tin oxide. The characterization of the cobalt oxides was carried out using the X-ray diffraction, Atomic force microscope, and Scanning electron microscope. In this context, the cobalt oxide crystal structure in the range of (−1.0 V)–(+1.9 V) was synthesized on different substrates and at extremely low temperatures (20 °C to 25 °C), using the cyclic voltammetry method, which is a simple one-stage way. Calculated band gap value for ITO/CoO2 as 2.5 eV shows a potential use of this electrode in solar cell applications.

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Badding, John V. "Cobalt oxide layers." Nature Materials 2, no. 4 (April 2003): 208–10. http://dx.doi.org/10.1038/nmat868.

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6

Young, Jay A. "Cobalt(II) Oxide." Journal of Chemical Education 78, no. 10 (October 2001): 1328. http://dx.doi.org/10.1021/ed078p1328.

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Sakhnenko, Nikolay, Maryna Ved’, and Ann Karakurkchi. "PECULIARITIES OF COBALT CONTAINING OXIDE COATINGS FORMATION ON SILUMIN." Ukrainian Chemistry Journal 86, no. 1 (February 5, 2020): 12–21. http://dx.doi.org/10.33609/0041-6045.86.1.2020.12-21.

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The process of mixed oxide coatings formation on a high-silicon aluminum alloy in a cobalt-containing pyrophosphate electrolyte by the plasma-electrolytic oxidation (PEO) method is studied. It was shown that AL25 chemical composition heterogeneity causes the consumption of a part of the anode current to homogenize the treated surface, which is reflected in minimizing the content of doping components at the initial processing stage. It was established that the growth of mixed oxides Al2O3·CoxOy relative mass is a function of time with a maximum at 55 minutes. The chemical, phase composition and surface morphology of the formed oxide layer depend on the oxidation time. The catalytic component content in the surface oxides varies from 0.2 to 23.3 at.% with an increase in processing time of 10 to 60 minutes. Maximum cobalt incorporation into the oxide layer occurs at PEO of 35–50 minutes, while the silicon content in the surface layers does not exceed 2 at.%, which is favorable for the catalytic properties. The cobalt oxide, preferably Co3O4, incorporation in the alumina α-Al2O3 matrix is visualized by the blue-violet color steroidal surface structures in the sites of micro-arc discharges. The alumina cobalt oxide mixture layers are characterized by a developed micro-globular surface which consists of spheroid conglomerate with an average size of 1–2 microns. There are some amorphous phases in the structure of mixed oxides due to non-equilibrium PEO conditions. The set of detected factors is a prerequisite for the high catalytic properties of oxide coatings. A promising field of Al2O3·CoxOy systems application is intra-cylinder catalysis in internal combustion engines.

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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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Koshtyal, Yury, Ilya Mitrofanov, Denis Nazarov, Oleg Medvedev, Artem Kim, Ilya Ezhov, Aleksander Rumyantsev, Anatoly Popovich, and Maxim Yu Maximov. "Atomic Layer Deposition of Ni-Co-O Thin-Film Electrodes for Solid-State LIBs and the Influence of Chemical Composition on Overcapacity." Nanomaterials 11, no. 4 (April 2, 2021): 907. http://dx.doi.org/10.3390/nano11040907.

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Nanostructured metal oxides (MOs) demonstrate good electrochemical properties and are regarded as promising anode materials for high-performance lithium-ion batteries (LIBs). The capacity of nickel-cobalt oxides-based materials is among the highest for binary transition metals oxide (TMOs). In the present paper, we report the investigation of Ni-Co-O (NCO) thin films obtained by atomic layer deposition (ALD) using nickel and cobalt metallocenes in a combination with oxygen plasma. The formation of NCO films with different ratios of Ni and Co was provided by ALD cycles leading to the formation of nickel oxide (a) and cobalt oxide (b) in one supercycle (linear combination of a and b cycles). The film thickness was set by the number of supercycles. The synthesized films had a uniform chemical composition over the depth with an admixture of metallic nickel and carbon up to 4 at.%. All samples were characterized by a single NixCo1-xO phase with a cubic face-centered lattice and a uniform density. The surface of the NCO films was uniform, with rare inclusions of nanoparticles 15–30 nm in diameter. The growth rates of all films on steel were higher than those on silicon substrates, and this difference increased with increasing cobalt concentration in the films. In this paper, we propose a method for processing cyclic voltammetry curves for revealing the influence of individual components (nickel oxide, cobalt oxide and solid electrolyte interface—SEI) on the electrochemical capacity. The initial capacity of NCO films was augmented with an increase of nickel oxide content.

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10

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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11

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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13

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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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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15

Feizi, Hadi, Robabeh Bagheri, Zhenlun Song, Jian-Ren Shen, Suleyman I. Allakhverdiev, and Mohammad Mahdi Najafpour. "Cobalt/Cobalt Oxide Surface for Water Oxidation." ACS Sustainable Chemistry & Engineering 7, no. 6 (February 18, 2019): 6093–105. http://dx.doi.org/10.1021/acssuschemeng.8b06269.

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Sun, Qiang, Zhong Wang, Da Wang, Zhe Hong, Mingdong Zhou, and Xuebing Li. "A review on the catalytic decomposition of NO to N2 and O2: catalysts and processes." Catalysis Science & Technology 8, no. 18 (2018): 4563–75. http://dx.doi.org/10.1039/c8cy01114a.

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Recent advances in the catalytic decomposition of NO have been overviewed and divided into three categories: metal oxide catalysts (including perovskites and rare earth oxides), supported metal oxide catalysts (including alkali metals, cobalt oxide and noble metals) and Cu-ZSM-5.

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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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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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Celen, Burak, Melik Bugra Ozcelik, Furkan Metin Turgut, Cisel Aras, Thyagesh Sivaraman, Yash Kotak, Christian Geisbauer, and Hans-Georg Schweiger. "Calendar ageing modelling using machine learning: an experimental investigation on lithium ion battery chemistries." Open Research Europe 2 (August 12, 2022): 96. http://dx.doi.org/10.12688/openreseurope.14745.1.

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Background: The phenomenon of calendar ageing continues to have an impact on battery systems worldwide by causing them to have undesirable operation life and performance. Predicting the degradation in the capacity can identify whether this phenomenon is occurring for a cell and pave the way for placing mechanisms that can circumvent this behaviour. Methods: In this study, the machine learning algorithms, Extreme Gradient Boosting (XGBoost) and artificial neural network (ANN) have been used to predict the calendar ageing data belonging to six types of cell chemistries namely, Lithium Cobalt Oxide, Lithium Iron Phosphate, Lithium Manganese Oxide, Lithium Titanium Oxide, Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide. Results: Prediction results with overall Mean Absolute Percentage Error of 0.0126 have been obtained for XGBoost algorithm. Among these results, Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide type cell chemistries stand out with their mean absolute percentage errors of 0.0035 and 0.0057 respectively. Also, algorithm fitting performance is relatively better for these chemistries at 100% state of charge and 60°C temperature compared to ANN results. ANN algorithm predicts with mean absolute error of approximately 0.0472 overall and 0.0238 and 0.03825 for Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide. The fitting performance of ANN for Nickle Manganese Cobalt Oxide at 100% state of charge and 60°C temperature is especially poor compared to XGBoost. Conclusions: For an electric vehicle battery calendar ageing prediction application, XGBoost can establish itself as the primary choice more easily compared to ANN. The reason is XGBoost’s error rates and fitting performance are more usable for such application especially for Nickel Cobalt Aluminum Oxide and Nickel Manganese Cobalt Oxide chemistries, which are amongst the most demanded cell chemistries for electric vehicle battery packs.

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Karakurkchi, Ann V., Nykolay D. Sakhnenko, Maryna V. Ved’, Ihor S. Luhovskyi, Hryhoriy A. Drobakha, and Maryna V. Mayba. "Features of Plasma Electrolytic Formation of Manganese- and Cobalt-Containing Composites on Aluminum Alloys." Advances in Materials Science and Engineering 2019 (August 7, 2019): 1–13. http://dx.doi.org/10.1155/2019/6381291.

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This paper presents the results of studies on the electrochemical treatment characteristics of aluminum and alloys in alkaline electrolytes. It is shown that the heterogeneity of the alloys composition complicates the formation of the surface oxide layer. To homogenize the treated surface and obtain oxide coatings doped with manganese and cobalt, electrolytes based on KOH and K4P2O7 with the addition of KMnO4 and CoSO4 were used. Plasma electrolytic oxidizing (PEO) in these electrolytes in the range of current densities 5–20 A/dm2 allows to obtain mixed oxide coatings which contained both aluminum oxide matrix and doping metal oxides Al2O3·MnOx and Al2O3·CoOy. It is shown that an increase in the PEO current density and the concentration of manganate- and cobalt(II) ions in the solution leads to an increase the content of dopant metals in the coatings outer layer. The incorporation of manganese and cobalt oxides in the composition of the surface layers was confirmed by the results of X-ray structural analysis. The rational modes of aluminum alloys PEO treatment were substantiated to obtain coatings with manganese and cobalt contents up to 25–40 аt.%. Formed oxide systems have a developed surface and high adhesion to the base metal and show an increased corrosion resistance and catalytic activity. This allows us to view them as promising materials for air- and water-cleaning technologies and internal combustion engine waste gas purification systems.

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Huang, Huanshao, Jiajun Wang, Junai Zhang, Jiye Cai, Jiang Pi, and Jun-Fa Xu. "Inspirations of Cobalt Oxide Nanoparticle Based Anticancer Therapeutics." Pharmaceutics 13, no. 10 (October 2, 2021): 1599. http://dx.doi.org/10.3390/pharmaceutics13101599.

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Cobalt is essential to the metabolism of all animals due to its key role in cobalamin, also known as vitamin B12, the primary biological reservoir of cobalt as an ultra-trace element. Current cancer treatment strategies, including chemotherapy and radiotherapy, have been seriously restricted by their side effects and low efficiency for a long time, which urges us to develop new technologies for more effective and much safer anticancer therapies. Novel nanotechnologies, based on different kinds of functional nanomaterials, have been proved to act as effective and promising strategies for anticancer treatment. Based on the important biological roles of cobalt, cobalt oxide nanoparticles (NPs) have been widely developed for their attractive biomedical applications, especially their potential for anticancer treatments due to their selective inhibition of cancer cells. Thus, more and more attention has been attracted to the preparation, characterization and anticancer investigation of cobalt oxide nanoparticles in recent years, which is expected to introduce novel anticancer treatment strategies. In this review, we summarize the synthesis methods of cobalt oxide nanoparticles to discuss the advantages and restrictions for their preparation. Moreover, we emphatically discuss the anticancer functions of cobalt oxide nanoparticles as well as their underlying mechanisms to promote the development of cobalt oxide nanoparticles for anticancer treatments, which might finally benefit the current anticancer therapeutics based on functional cobalt oxide nanoparticles.

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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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Andreev, Andrey S., Serguey F. Tikhov, Aleksey N. Salanov, Svetlana V. Cherepanova, Olga B. Lapina, Vasiliy A. Bolotov, Yuriy Yu Tanashev, Jean Baptiste d’Espinose de Lacaillerie, and Vladislav A. Sadykov. "Design of Al₂O₃/CoAlO/CoAl Porous Ceramometal for Multiple Applications as Catalytic Supports." Advanced Materials Research 702 (May 2013): 79–87. http://dx.doi.org/10.4028/www.scientific.net/amr.702.79.

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Porous ceramometal Al2O3/CoAlO/CoAl was studied by set of physicochemical techniques such as XRD, SEM, internal field59Co and27Al MAS NMR, and porosity measurements. They revealed the cermet containing three parts. First, cobalt-free large porous alumina particles which surrounded by the second oxide part representing spinel CoxAl3-xO4(x=1,2,3) oxides. And third, oxygen-free metallic part consists of cobalt metal particles covered by Co-Al oxide protecting the metallic part from oxidation. Porosity measurements ascertained high porosity (60%) and good SSA (122 m2/g). Also the enhanced adsorption of microwaves due to metallic particles randomly distributed in oxides was found.

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Colley, Saul E., Richard G. Copperthwaite, Graham J. Hutchings, Gary A. Foulds, and Neil J. Coville. "Cobalt/manganese oxide catalysts." Applied Catalysis A: General 84, no. 1 (May 1992): 1–15. http://dx.doi.org/10.1016/0926-860x(92)80335-a.

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Grimes, Robin W., and K. Peter D. Lagerlof. "Polymorphs of Cobalt Oxide." Journal of the American Ceramic Society 74, no. 2 (February 1991): 270–73. http://dx.doi.org/10.1111/j.1151-2916.1991.tb06873.x.

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Mugheri, Abdul Qayoom, Aneela Tahira, Umair Aftab, Adeel Liaquat Bhatti, Ramesh Lal, Muhammad Ali Bhatti, Ghulam Zuhra Memon, et al. "Chemically Coupled Cobalt Oxide Nanosheets Decorated onto the Surface of Multiwall Carbon Nanotubes for Favorable Oxygen Evolution Reaction." Journal of Nanoscience and Nanotechnology 21, no. 4 (April 1, 2021): 2660–67. http://dx.doi.org/10.1166/jnn.2021.19108.

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Cobalt oxide has been widely investigated among potential transition metal oxides for the electrochemical energy conversion, storage, and water splitting. However, they have inherently low electronic conductivity and high corrosive nature in alkaline media. Herein, we propose a promising and facile approach to improve the conductivity and charge transport of cobalt oxide Co3O4 through chemical coupling with well-dispersed multiwall carbon nanotubes (MWCNTs) during hydrothermal treatment. The morphology of prepared composite material consisting of nanosheets which are anchored on the MWCNTs as confirmed by scanning electron microscopy (SEM). A cubic crystalline system is exhibited by the cobalt oxide as confirmed by the X-ray diffraction study. The Co, O, and C are the only elements present in the composite material. FTIR study has indicated the successful coupling of cobalt oxide with MWCNTs. The chemically coupled cobalt oxide onto the surface of MWCNTs composite is found highly active towards oxygen evolution reaction (OER) with a low onset potential 1.44 V versus RHE, low overpotential 262 mV at 10 mAcm-2 and small Tafel slope 81 mV dec-1. For continuous operation of 40 hours during durability test, no decay in activity was recorded. Electrochemical impedance study further revealed a low charge transfer resistance of 70.64 Ohms for the composite material during the electrochemical reaction and which strongly favored OER kinetics. This work provides a simple, low cost, and smartly designing electrocatalysts via hydrothermal reaction for the catalysis and energy storage applications.

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Liu, Zhifeng, Chonghao Ma, Qijun Cai, Tiantian Hong, Keying Guo, and Lu Yan. "Promising cobalt oxide and cobalt oxide/silver photocathodes for photoelectrochemical water splitting." Solar Energy Materials and Solar Cells 161 (March 2017): 46–51. http://dx.doi.org/10.1016/j.solmat.2016.11.026.

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Gogoi, M., and B. K. Das. "Synthesis of Nanostructured Cobalt Oxides using Cobalt(II) Fumarate Hydrate as Metal-Organic Precursor." Asian Journal of Chemistry 32, no. 12 (2020): 3144–50. http://dx.doi.org/10.14233/ajchem.2020.22970.

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A series of nanostructured cobalt oxides have been prepared from a metal-organic precursor viz. [Co(fum)(H2O)4]·H2O (fum = fumarate) by using capping agents, ethylene glycol and polyethylene glycol via thermal and solvothermal decomposition in ethanol and also by doping with RuCl3·xH2O via solvothermal route. The nano oxides were characterized by IR, UV-vis spectroscopy, powder XRD, SEM and TEM analysis. The nano oxides exhibit varied morphologies and particle sizes. The TEM images reveal homogeneously distributed particles for all the oxides. The band gap energy values the Ru-doped cobalt oxide was found to be lower than the generally accepted values.

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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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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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Patel, Charula, Nilesh Bhatt, and Srinivas Palanki. "Assessment of Manganese Oxide and Cobalt Oxide Catalysts for Three Way Catalytic Converter." Kataliz v promyshlennosti 20, no. 4 (July 20, 2020): 286–302. http://dx.doi.org/10.18412/1816-0387-2020-4-286-302.

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Raising number of vehicles emits pollutants responsible for one third of total air pollution. Carbon monoxide (CO), unburned hydrocarbons (HC), and nitrogen oxides (NOx) are the main pollutants from petrol engines. It requires stringent vehicular emission norms to be followed for controlling it. Three Way Catalytic Converter (TWCC) contain Platinum Group Metals (PGMs) as catalyst to reduce exhaust emission and is widely used method that fulfills these standards. Because of high cost of PGMs and considerable advancement in metal oxide preparatory methods, metal oxide catalysts have gained more attraction. Manganese oxide (MnOx) and Cobalt Oxide (CoOx) have displayed impressive redox reactions at lower temperature. MnOx seems to be a suitable contender of Oxygen Storage Capacity (OSC) and Cobalt oxide (CoOx) has displayed an excellent catalytic activity for HC and CO oxidation. Hence, these catalysts attract the attention of researchers. Present paper assesses the prospect of MnOx and CoOx as catalysts for the TWCC for redox reactions of CO, HC and NOx and also in terms of OSC and T50 temperature. It is found that CoOx and MnOx both low cost metal oxide catalysts stand a good chance to replace the noble metals for TWCC.

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Conrath, Elodie, and Patrice Berthod. "Oxide Spallation During Post-isothermal High Temperature Oxidation Cooling of Cr-rich Cast Alloys Highly Alloyed with Hf." Open Materials Science Journal 10, no. 1 (September 30, 2016): 89–100. http://dx.doi.org/10.2174/1874088x01610010089.

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Cobalt, nickel and iron-based alloys containing 25wt.%Cr and strengthened either by chromium carbides or by HfC were oxidized at 1000, 1100 and 1200°C to obtain external oxide scales. The spallation of these oxides during the post-oxidation cooling was studied by exploiting the cooling part of the thermogravimetry curves. The best resistant alloys against scale spallation were the iron-based alloys which did not lose oxide. The nickel-based alloys well behaved too. The worst alloys were the cobalt alloys, principally due to the complex composition of the oxide scales. Beside the base element, the thickness of the oxide was also identified as a major parameter. The presence of Hf with contents much higher than usual was also beneficial for the resistance against spallation.

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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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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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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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37

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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38

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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39

Govindasamy, Rajakumar, Vaishnavi Raja, Sonalika Singh, Mydhili Govindarasu, Sulthana Sabura, Kaliaperumal Rekha, V. Devi Rajeswari, et al. "Green Synthesis and Characterization of Cobalt Oxide Nanoparticles Using Psidium guajava Leaves Extracts and Their Photocatalytic and Biological Activities." Molecules 27, no. 17 (September 1, 2022): 5646. http://dx.doi.org/10.3390/molecules27175646.

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The advanced technology for synthesizing nanoparticles utilizes natural resources in an environmentally friendly manner. Additionally, green synthesis is preferred to chemical and physical synthesis because it takes less time and effort. The green synthesis of cobalt oxide nanoparticles has recently risen due to its physico-chemical properties. In this study, many functional groups present in Psidium guajava leaf extracts are used to stabilize the synthesis of cobalt oxide nanoparticles. The biosynthesized cobalt oxide nanoparticles were investigated using UV-visible spectroscopic analysis. Additionally, Fourier-transform infrared spectroscopy revealed the presence of carboxylic acids, hydroxyl groups, aromatic amines, alcohols and phenolic groups. The X-ray diffraction analysis showed various peaks ranging from 32.35 to 67.35°, and the highest intensity showed at 36.69°. The particle size ranged from 26 to 40 nm and confirmed the average particle size is 30.9 nm. The green synthesized P. guajava cobalt oxide nanoparticles contain cobalt as the major abundant element, with 42.26 wt% and 18.75 at% confirmed by the EDAX techniques. SEM images of green synthesized P. guajava cobalt oxide nanoparticles showed agglomerated and non-uniform spherical particles. The anti-bacterial activity of green synthesized P. guajava cobalt oxide nanoparticles was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli with a 7 to 18 mm inhibitory zone. The photocatalytic activity was evaluated using green synthesized P. guajava cobalt oxide nanoparticles and observed 79% of dye degradation. The MTT assay of P. guajava cobalt oxide nanoparticles showed an excellent cytotoxic effect against MCF 7 and HCT 116 cells compared to normal cells. The percentage of cell viability of P. guajava cobalt oxide nanoparticles was observed as 90, 83, 77, 68, 61, 58 and 52% for MCF-7 cells and 82, 70, 63, 51, 43, 40, and 37% for HCT 116 cells at the concentration of 1.53, 3.06, 6.12, 12.24, 24.48, 50, and 100 μg/mL compared to control cells. These results confirmed that green synthesized P. guajava cobalt oxide nanoparticles have a potential photocatalytic and anti-bacterial activity and also reduced cell viability against MCF-7 breast cancer and HCT 116 colorectal cancer cells.

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Sun, Junyong, Tian Gan, Cui Yang, Zhaoxia Shi, Kejing Huang, and Yanming Liu. "Novel electroanalytical platform based on bimetallic oxide nanospheres for the sensitive determination of Rhodamine B." Canadian Journal of Chemistry 92, no. 7 (July 2014): 640–46. http://dx.doi.org/10.1139/cjc-2014-0118.

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In this work, uniform cobalt and nickel bimetallic oxides were formed by calcining the carbon templates, which were then modified on a glassy carbon electrode (cobalt–nickel oxide/GCE) as a novel system for the preparation of an electrochemical sensing platform. The electrochemical oxidation behavior of Rhodamine B (RB) at the cobalt–nickel oxide/GCE was investigated using differential pulse voltammetry under optimal conditions; the high electrocatalytic activity of the modified electrode toward analysis of RB was indicated. In addition, a linear range of 0.03−1.0 μmol L–1 and a low detection limit of 5.3 nmol L–1 (S/N = 3) for RB detection were obtained. Finally, the developed method with good stability and sensitivity was successfully applied for RB determination in food samples extract.

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41

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, 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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Song, Yu, Mingyue Zhang, Tianyu Liu, Tianjiao Li, Di Guo, and Xiao-Xia Liu. "Cobalt-Containing Nanoporous Nitrogen-Doped Carbon Nanocuboids from Zeolite Imidazole Frameworks for Supercapacitors." Nanomaterials 9, no. 8 (August 2, 2019): 1110. http://dx.doi.org/10.3390/nano9081110.

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Pyrolyzing metal–organic frameworks (MOFs) typically yield composites consisting of metal/metal oxide nanoparticles finely dispersed on carbon matrices. The blend of pseudocapacitive metal oxides and conductive metals, as well as highly porous carbon networks, offer unique opportunities to obtain supercapacitor electrodes with mutually high capacitances and excellent rate capabilities. Herein, we demonstrate nitrogen-doped carbon nanocuboid arrays grown on carbon fibers and incorporating cobalt metal and cobalt metal oxides. This composite was synthesized via pyrolysis of a chemical bath deposited MOF, cobalt-containing zeolite imidazole framework (Co–ZIF). The active materials for charge storage are the cobalt oxide and nitrogen-doped carbon. Additionally, the Co metal and the nanoporous carbon network facilitated electron transport and the rich nanopores in each nanocuboid shortened ion diffusion distance. Benefited from these merits, our Co–ZIF-derived electrode delivered an areal capacitance of 1177 mF cm−2 and excellent cycling stability of ~94% capacitance retained after 20,000 continuous charge–discharge cycles. An asymmetric supercapacitor prototype having the Co–ZIF-derived hybrid material (positive electrode) and activated carbon (negative electrode) achieved a maximal volumetric energy density of 1.32 mWh cm−3 and the highest volumetric power density of 376 mW cm−3. This work highlights the promise of metal–metal oxide–carbon nanostructured composites as electrodes in electrochemical energy storage devices.

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Olivo, Alberto, Berceste Beyribey, Hwan Kim, and Joshua Persky. "Cobalt oxide enhanced lanthanum strontium cobalt ferrite electrode for solid oxide fuel cells." Main Group Chemistry 21, no. 1 (April 8, 2022): 195–207. http://dx.doi.org/10.3233/mgc-210114.

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A Co3O4 enhanced La0.8Sr0.2Co0.5Fe0.5O3 - δ (LSCF) electrode is developed for use in air electrodes with proton conducting solid oxide fuel cell (SOFC). The incipient wetness impregnation method enables Co3O4 nanoparticles on the LSCF surface without altering the bulk porosity of the LSCF electrode. The polarization resistance of LSCF electrodes is significantly reduced by Co3O4 doping, and both charge transfer and diffusion/conversion resistances were positively affected. The highest reduction in charge transfer resistance is obtained at 700 °C, which is increased from 21 % to 32 % through reduction of po2. Conversely, the highest reduction in diffusion/conversion resistance is achieved at 550 °C. By increasing po2, the reduction is increased from 57 % to 66 % and its activation energy is reduced up to 33 % compared to pure LSCF. The lowest total area specific resistances obtained under air are 1.45 Ω·cm2, 2.95 Ω·cm2, 6.75 Ω·cm2 and 16.45 Ω·cm2 at 700 °C, 650 °C, 600 °C and 550 °C, respectively.

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Solsona, Benjamin, Thomas E. Davies, Tomas Garcia, Isabel Vázquez, Ana Dejoz, and Stuart H. Taylor. "Total oxidation of propane using nanocrystalline cobalt oxide and supported cobalt oxide catalysts." Applied Catalysis B: Environmental 84, no. 1-2 (October 2008): 176–84. http://dx.doi.org/10.1016/j.apcatb.2008.03.021.

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Zhang, Weidong, Paola Anguita, Javier Díez-Ramírez, Claude Descorme, Jose Luis Valverde, and Anne Giroir-Fendler. "Comparison of Different Metal Doping Effects on Co3O4 Catalysts for the Total Oxidation of Toluene and Propane." Catalysts 10, no. 8 (August 3, 2020): 865. http://dx.doi.org/10.3390/catal10080865.

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Metal-doped (Mn, Cu, Ni, and Fe) cobalt oxides were prepared by a coprecipitation method and were used as catalysts for the total oxidation of toluene and propane. The metal-doped catalysts displayed the same cubic spinel Co3O4 structure as the pure cobalt oxide did; the variation of cell parameter demonstrated the incorporation of dopants into the cobalt oxide lattice. FTIR spectra revealed the segregation of manganese oxide and iron oxide. The addition of dopant greatly influenced the crystallite size, strain, specific surface area, reducibility, and subsequently the catalytic performance of cobalt oxides. The catalytic activity of new materials was closely related to the nature of the dopant and the type of hydrocarbons. The doping of Mn, Ni, and Cu favored the combustion of toluene, with the Mn-doped one being the most active (14.6 × 10−8 mol gCo−1 s−1 at 210 °C; T50 = 224 °C), while the presence of Fe in Co3O4 inhibited its toluene activity. Regarding the combustion of propane, the introduction of Cu, Ni, and Fe had a negative effect on propane oxidation, while the presence of Mn in Co3O4 maintained its propane activity (6.1 × 10−8 mol gCo−1 s−1 at 160 °C; T50 = 201 °C). The excellent performance of Mn-doped Co3O4 could be attributed to the small grain size, high degree of strain, high surface area, and strong interaction between Mn and Co. Moreover, the presence of 4.4 vol.% H2O badly suppressed the activity of metal-doped catalysts for propane oxidation, among them, Fe-doped Co3O4 showed the best durability for wet propane combustion.

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Chen, Tao, Shengli Pang, Xiangqian Shen, Xuening Jiang, and Wenzhi Wang. "Evaluation of Ba-deficient PrBa1−xFe2O5+δ oxides as cathode materials for intermediate-temperature solid oxide fuel cells." RSC Advances 6, no. 17 (2016): 13829–36. http://dx.doi.org/10.1039/c5ra19555a.

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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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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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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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Journal articles on the topic 'Cobalt oxide'

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