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Journal articles on the topic 'Cobalt oxides'

Author: Grafiati
Published: 4 June 2021
Last updated: 31 May 2022

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1

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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2

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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3

Ved', M. V. "Synthesis and functional properties of mixed titanium and cobalt oxides." Functional materials 24, no. 4 (December 18, 2017): 534–40. http://dx.doi.org/10.15407/fm24.04.534.

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4

Koshibae, W., K. Tsutsui, and S. Maekawa. "Thermopower in cobalt oxides." Physical Review B 62, no. 11 (September 15, 2000): 6869–72. http://dx.doi.org/10.1103/physrevb.62.6869.

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5

Neha, Neha, Ram Prasad, and Satya Vir Singh. "Simultaneous Catalytic Oxidation of a Lean Mixture of CO-CH4 over Spinel Type Cobalt Based Oxides." Bulletin of Chemical Reaction Engineering & Catalysis 15, no. 2 (June 12, 2020): 490–500. http://dx.doi.org/10.9767/bcrec.15.2.6499.490-500.

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A series of nickel-cobalt bimetal oxides in varying molar ratios and its single metal oxides were synthesized by reactive calcination of coprecipitated basic-carbonates. Several characterization techniques, such as: Bruneuer Emmett Teller (BET), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infra Red (FTIR), and Hydrogen Temperature Programmed Reduction (H2-TPR), were performed over the oxides. Activities of oxides were evaluated in methane total oxidation in the presence or the absence of CO. The best catalytic performance was observed over NiCo catalyst with a Ni/Co molar ratio of 1:1, and the complete conversion of CO-CH4 mixture was achieved at 390 °C. Moreover, the presence of carbon monoxide improves CH4 total oxidation over nickel-cobalt mixed oxides. Structural analysis reveals that the insertion of nickel into the spinel lattice of cobalt oxide causes the structural disorder, which probably caused the increase of the amount of octahedrally coordinated divalent nickel cations that are responsible for catalytic activity. Stability of the best-performed catalyst has been tested in the two conditions, showing remarkable long-term stability and thermal stability, however, showed deactivation after thermally ageing at 700 °C. Copyright © 2020 BCREC Group. All rights reserved
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6

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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7

Kallumottakkal, Muhammed, Mousa I. Hussein, Yousef Haik, and Tarik Bin Abdul Latef. "Functionalized-CNT Polymer Composite for Microwave and Electromagnetic Shielding." Polymers 13, no. 22 (November 12, 2021): 3907. http://dx.doi.org/10.3390/polym13223907.

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In this research work, we studied the microwave properties of multi-wall carbon nanotube (MWCNT) surface functionalized with metallic oxides composites. Three different concentrations (5%, 10%, and 20%) of metallic oxides were used, namely cobalt, iron, and cobalt ferrite. The surface-decorated CNTS were impregnated into polyurethane (PU) matrix. The surface-decorated MWCNTs and the MWCNTs-PU composites were characterized using electron microscopy. The dielectric properties of the samples are studied using an open-ended coaxial probe technique in a wide frequency range of (5–50 GHz). The metallic oxide-decorated surface MWCNTs-PU composites demonstrated different microwave-frequency absorption characteristics depending on the concentration of the metallic oxides.
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8

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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9

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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10

FOUAD, O. A., and M. S. EL-SHALL. "MICROWAVE IRRADIATION ASSISTED GROWTH OF Cu, Ni, Co METALS AND/OR OXIDES NANOCLUSTERS AND THEIR CATALYTIC PERFORMANCE." Nano 07, no. 05 (October 2012): 1250034. http://dx.doi.org/10.1142/s1793292012500348.

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Copper, nickel and cobalt metals and oxides needle-like shape nanoclusters have been synthesized successfully by chemical reduction in solution without using a surfactant. XRD analyses showed that copper and nickel metals could be synthesized in a short time period by a microwave irradiation (MWI) — assisted step wise reduction of metal ions in basic solution using hydrazine as a reducing agent whereas cobalt was mainly precipitated in the form of either hydroxide or oxide. TEM images showed that the size of needle-like shape nanoclusters varying from about 5 nm to few hundred nanometers length. On the other hand, copper and cobalt showed high catalytic activity toward CO oxidation than that of nickel. The mechanism of catalytic oxidation reactions over unsupported metals and oxides are also discussed.
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11

Song, Myoung Youp, Ho Rim, and Hye Ryoung Park. "Electrochemical characteristics of cobalt-substituted lithium nickel oxides synthesized from lithium hydro-oxide and nickel and cobalt oxides." Ceramics International 38, no. 8 (December 2012): 6591–97. http://dx.doi.org/10.1016/j.ceramint.2012.05.044.

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12

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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13

Bordoloi, Ankur, Miguel Sanchez, Heshmat Noei, Stefan Kaluza, Dennis Großmann, Yuemin Wang, Wolfgang Grünert, and Martin Muhler. "Catalytic Behaviour of Mesoporous Cobalt-Aluminum Oxides for CO Oxidation." Journal of Catalysts 2014 (October 1, 2014): 1–9. http://dx.doi.org/10.1155/2014/807545.

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Ordered mesoporous materials are promising catalyst supports due to their uniform pore size distribution, high specific surface area and pore volume, tunable pore sizes, and long-range ordering of the pore packing. The evaporation-induced self-assembly (EISA) process was applied to synthesize mesoporous mixed oxides, which consist of cobalt ions highly dispersed in an alumina matrix. The characterization of the mesoporous mixed cobalt-aluminum oxides with cobalt loadings in the range from 5 to 15 wt% and calcination temperatures of 673, 973, and 1073 K indicates that Co2+ is homogeneously distributed in the mesoporous alumina matrix. As a function of the Co loading, different phases are present comprising poorly crystalline alumina and mixed cobalt aluminum oxides of the spinel type. The mixed cobalt-aluminum oxides were applied as catalysts in CO oxidation and turned out to be highly active.
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14

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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15

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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16

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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17

Pan, Shencheng, Xin Mao, Juan Yu, Lin Hao, Aijun Du, and Bing Li. "Remarkably improved oxygen evolution reaction activity of cobalt oxides by an Fe ion solution immersion process." Inorganic Chemistry Frontiers 7, no. 18 (2020): 3327–39. http://dx.doi.org/10.1039/d0qi00385a.

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18

Sakita, Alan M. P., Rodrigo Della Noce, Cecílio S. Fugivara, and Assis V. Benedetti. "On the cobalt and cobalt oxide electrodeposition from a glyceline deep eutectic solvent." Physical Chemistry Chemical Physics 18, no. 36 (2016): 25048–57. http://dx.doi.org/10.1039/c6cp04068c.

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19

Song, Hee Chan, Seungtaeg Oh, Sang Hoon Kim, Si Woo Lee, Song Yi Moon, Hanseul Choi, Soo-Hyun Kim, Yongman Kim, Jihun Oh, and Jeong Young Park. "The effect of the oxidation states of supported oxides on catalytic activity: CO oxidation studies on Pt/cobalt oxide." Chemical Communications 55, no. 64 (2019): 9503–6. http://dx.doi.org/10.1039/c9cc03770e.

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20

Kajitani, Tsuyoshi, Yuzuru Miyazaki, Kei Hayashi, Kunio Yubuta, X. Y. Huang, and W. Koshibae. "Thermoelectric Energy Conversion and Ceramic Thermoelectrics." Materials Science Forum 671 (January 2011): 1–20. http://dx.doi.org/10.4028/www.scientific.net/msf.671.1.

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Oxide thermoelectrics are relatively new materials that are workable at temperatures in the range of 400K≤T≤1200K. There are several types of thermoelectric oxide, namely, cobalt oxides (p-type semi-conductors), manganese oxides (n-type) and zinc oxides (n-type semi-conductors) for high temperature energy harvesting. The Seebeck coefficient of 3d metal oxide thermoelectrics is relatively high due to either high density of states at Fermi surfaces or spin entropy flow associated with the carrier flow. The spin entropy part dominates the Seebeck coefficient of 3d-metal oxides at temperatures above 300K. Introduction of impurity particles or quantum-well structures to enhance thermionic emission and energy filtering effects for the oxide semiconductors may lead to a significant improvement of thermoelectric performance.
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21

Liu, Hong Quan, Ying Song, and Fu Ping Wang. "Progress in Researches on the Layered Cobalt Oxides for Thermoelectric Devices." Key Engineering Materials 336-338 (April 2007): 814–17. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.814.

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The layered cobalt oxides as thermoelectric (TE) materials are introduced in detail on their developments, representative systems, some theories, unsolved problems and approaches for improving performances. TE performances of the layered cobalt oxides are discussed from structures, doped situations, processes and the dimensionless figure of merit. In contrast with other TE materials, the layered cobalt oxides show many promising applications. The theory of Seebeck coefficient and hopping conduction mechanism in the layered cobalt oxides are discussed. Heike formula explains that Seebeck coefficient origins from electronic spin states and proportions of different value states of Co ion. An unbalance of the spin and orbital degrees of freedom between Co3+ and Co4+ sites results in the large Seebeck coefficient. On the basis of the Boltzmann transport equation, Seebeck coefficient is decided by energy band structures. High state density near Fermi Energy band is responsible for the coexistence of large Seebeck coefficient and high electrical conductivity. Hopping conduction mechanism found in experiments is a main transport way of charge carriers at high temperature for the layered cobalt oxides. Through different materials systems and theories analysis, unsolved problems and new approaches for improving TE performances are put forward.
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22

Koinuma, Michio, Tomohiko Hirae, and Yasumichi Matsumoto. "Electrochemical preparation of cobalt oxide using an autoclave electrolytic cell." Journal of Materials Research 13, no. 4 (April 1998): 837–39. http://dx.doi.org/10.1557/jmr.1998.0109.

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Polycrystalline films of cobalt oxides (Co3O4and CoOOH) with and without Sm were fabricated on platinum substrates by electrochemical oxidation in an autoclave. The cobalt oxides were directly crystallized at temperatures higher than about 100 °C during electrolysis. The composition of the cobalt oxides strongly depended on the electrode potential; i.e., Co3O4and CoOOH were formed in non-noble and relatively noble potential regions, respectively. When Sm was incorporated in the CoOOH by the electrolysis in solutions containing Sm3+, only theclattice constant was increased due to an expansion in the layer structure.
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23

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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24

du Plessis, Hester, Roy Forbes, Werner Barnard, Alta Ferreira, and Axel Steuwer. "In situ reduction study of cobalt model Fischer-Tropsch synthesis catalyst." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C948. http://dx.doi.org/10.1107/s2053273314090512.

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Fischer-Tropsch (FT) synthesis is an important process to manufacture hydrocarbons and oxygenated hydrocarbons from mixtures of carbon monoxide and hydrogen (syngas). The catalysis process occurs on for example cobalt metal surfaces at elevated temperatures and pressures. A fundamental understanding of the reduction pathway of supported cobalt oxides, and the intermediate species present during the activation, can assist in developing improved industrial supported cobalt catalysts. Measurements were done during in-situ hydrogen activation of a model Co/alumina catalyst using in-situ synchrotron X-ray powder diffraction and pair-distribution function (PDF) analysis. Strong metal-support interactions between the Co and the support1 can make the catalyst more stable towards sintering. The supported cobalt oxide catalyst precursors have to undergo reductive pre-treatments before their use as FT catalysts. During activation the cobalt oxides evolve, resulting in the formation of metallic cobalt depending on temperature, pressure of activation gases, concentration, time of exposure etc. The effect of hydrogen activation treatments on model catalysts were reported previously [1,2], however analysis of the alumina support phases was excluded from the interpretation by subtraction and normalisation. The PDF refinement accounted for all cobalt present in the catalyst sample and after reduction mainly Co(fcc) with a little Co(hcp) was found to be present. This is a novel approach to in situ PDF analysis of catalysts containing a mixture of phases [3].
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25

Monk, Paul M. S., Sarah L. Chester, Davis S. Higham, and Robert D. Partridge. "Electrodeposition of cobalt oxide doped with additional metal oxides." Electrochimica Acta 39, no. 15 (October 1994): 2277–84. http://dx.doi.org/10.1016/0013-4686(94)c0235-5.

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26

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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27

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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28

Lendzion-Bieluń, Zofia, Rafał Pelka, and Łukasz Czekajło. "Characterization of FeCo based catalyst for ammonia decomposition. The effect of potassium oxide." Polish Journal of Chemical Technology 16, no. 4 (December 1, 2014): 111–16. http://dx.doi.org/10.2478/pjct-2014-0080.

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Abstract FeCo fused catalyst was obtained by fusing iron and cobalt oxides with an addition of calcium, aluminium, and potassium oxides (CaO, Al2O3, K2O). An additional amount of potassium oxide was inserted by wet impregnation. Chemical composition of the prepared catalysts was determined with an aid of the XRF method. On the basis of XRD analysis it was found that cobalt was built into the structure of magnetite and solid solution of CoFe2O4 was formed. An increase in potassium content develops surface area of the reduced form of the catalyst, number of adsorption sites for hydrogen, and the ammonia decomposition rate. The nitriding process of the catalyst slows down the ammonia decomposition.
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29

Zhang, Wei, Chao Ping Zhang, and De Jun Shen. "Preparation of Cobalt and Copper Superfine Composite Oxides and Magnetic Property." Advanced Materials Research 150-151 (October 2010): 687–92. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.687.

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A series of Co–Cu composite oxides with different susceptibility were prepared by a microemulsion method. XRD, TEM, EDS，FT-IR spectra , TG-DSC and magnetic balance were used to characterize the structure , thermostability and susceptibility of the composite oxides. The results indicate that sintering temperature has an apparent effect on the formation of the spinel structure, As the composite powders are annealed at 500 °C,the Co–Cu composite oxide was CuO 、CoO、 Cu2CoO3 and Co3O4 , but the susceptibilities of Co-Cu composite were found decreased with the annealing, and particle sizes of the composite oxides were increased in the beginning, and then became lower with the annealing .The element Co is found when the calcinations temperature is lower than 300°C.particle sizes of the composite oxides were increased at beginning, then reduced, and increased when over 500°C
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30

Shirzadi, A. A., and E. R. Wallach. "Novel Method for Diffusion Bonding Superalloys and Aluminium Alloys (USA Patent 6,669,534 B2, European Patent Pending)." Materials Science Forum 502 (December 2005): 431–36. http://dx.doi.org/10.4028/www.scientific.net/msf.502.431.

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A novel method for diffusion bonding metallic alloys with stable surface oxide films (e.g. nickel and cobalt base superalloys and aluminium alloys) has been developed. The stable oxides on the faying surfaces of these alloys are replaced, prior to the bonding process, with a very thin metallic layer and/or less stable oxides, using a proprietary non-chemical oxide removal method based on the use of gallium. This new method is very rapid and neither requires the use of any sophisticated equipment nor is a costly process. Bonding is then readily achieved by either solid-state or transient-liquid-phase (TLP) diffusion bonding. Using this method, bonds in nickelbase and cobalt-base superalloys with “virtually invisible” bond interfaces and bonds in aluminium alloys with strengths as high as those of the parent alloys can be produced.
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31

Rabani, Iqra, Jeseung Yoo, Hyo-Sun Kim, Do Van Lam, Sajjad Hussain, K. Karuppasamy, and Young-Soo Seo. "Highly dispersive Co3O4 nanoparticles incorporated into a cellulose nanofiber for a high-performance flexible supercapacitor." Nanoscale 13, no. 1 (2021): 355–70. http://dx.doi.org/10.1039/d0nr06982e.

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Transition metal oxides used as electrode materials for flexible supercapacitors have attracted huge attention due to their high specific capacitance and surface-to-volume ratio, specifically for cobalt oxide (Co3O4) nanoparticles.
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32

Salam, M. Abdus, and Suriati Sufian. "Hydrogen Adsorption Capacity Investigation of Ni-Co-Al Mixed Oxides." Advanced Materials Research 917 (June 2014): 360–64. http://dx.doi.org/10.4028/www.scientific.net/amr.917.360.

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Micro-mesoporous mixed oxides containing nickel, cobalt and aluminum have been synthesized using conventional coprecipitation method. FESEM and HRTEM analyses demonstrated the flower and hexagonal plate-like nanostructured of mixed oxides. Different mixed oxide formation, homogenous metal dispersion, textural properties were investigated using XRD, ICP-MS and BET (N2 adsorption-desorption) techniques. nanostructured mixed oxides exhibited 2.6 wt% hydrogen adsorption that were studied using temperature programmed reduction-adsorption-desorption (H2-TPR/TPD) and thermogravimetric and differential thermal analysis (TGA-DTA) techniques. Investigation corresponds that morphologies, textural properties and surface energy of mixed oxides are important in hydrogen adsorption.
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33

Fester, Jakob, Alex Walton, Zheshen Li, and Jeppe V. Lauritsen. "Gold-supported two-dimensional cobalt oxyhydroxide (CoOOH) and multilayer cobalt oxide islands." Physical Chemistry Chemical Physics 19, no. 3 (2017): 2425–33. http://dx.doi.org/10.1039/c6cp07901f.

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34

Gerold, Eva, Stefan Luidold, and Helmut Antrekowitsch. "Selective Precipitation of Metal Oxalates from Lithium Ion Battery Leach Solutions." Metals 10, no. 11 (October 29, 2020): 1435. http://dx.doi.org/10.3390/met10111435.

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The separation of cobalt and nickel from sulfatic leach liquors of spent lithium-ion batteries is described in this paper. In addition to the base metals (e.g., cobalt and nickel), components such as manganese and lithium are also present in such leach liquors. The co-precipitation of these contaminants can be prevented during leach liquor processing by selective precipitation. For the recovery of a cobalt-nickel mixed material, oxalic acid serves as a suitable reagent. For the optimization of the precipitation retention time and yield, the dependence of the oxalic acid addition must be taken into account. In addition to efficiency, attention must also be given to the purity of the product. After this procedure, further processing of the products by calcination into oxides leads to better marketability. A series of experiments confirms the suitability of oxalic acid for precipitation of cobalt and nickel as a mixed oxalate from sulfatic liquors and also suggests a possible route for further processing of the products with increased marketability. The impurities in the resulting oxides are below 3%, whereby a sufficiently high purity of the mixed oxide can be achieved.
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35

Cendrowski, Krzysztof, Anna Zenderowska, Agata Bieganska, and Ewa Mijowska. "Graphene nanoflakes functionalized with cobalt/cobalt oxides formation during cobalt organic framework carbonization." Dalton Transactions 46, no. 24 (2017): 7722–32. http://dx.doi.org/10.1039/c7dt01048f.

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36

Swennen, B., J. P. Buchet, D. Stanescu, D. Lison, and R. Lauwerys. "Epidemiological survey of workers exposed to cobalt oxides, cobalt salts, and cobalt metal." Occupational and Environmental Medicine 50, no. 9 (September 1, 1993): 835–42. http://dx.doi.org/10.1136/oem.50.9.835.

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37

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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38

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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39

Morita, Y., J. Poulsen, K. Sakai, T. Motohashi, T. Fujii, I. Terasaki, H. Yamauchi, and M. Karppinen. "Oxygen nonstoichiometry and cobalt valence in misfit-layered cobalt oxides." Journal of Solid State Chemistry 177, no. 9 (September 2004): 3149–55. http://dx.doi.org/10.1016/j.jssc.2004.05.023.

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40

Gulino, Antonino, and Ignazio Fragalà. "Cobalt hexafluoroacetylacetonate polyether adducts for thin films of cobalt oxides." Inorganica Chimica Acta 358, no. 15 (December 2005): 4466–72. http://dx.doi.org/10.1016/j.ica.2005.07.031.

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41

Sugiyama, J., J. H. Brewer, E. J. Ansaldo, H. Itahara, M. Bayer, and T. Tani. "μSR studies on layered cobalt oxides." Physica B: Condensed Matter 326, no. 1-4 (February 2003): 518–21. http://dx.doi.org/10.1016/s0921-4526(02)01680-0.

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42

Huang, Zhifang, Yan Zhao, Yuehong Song, Yawen Li, Gongjuan Wu, Hongjiao Tang, and Jingzhe Zhao. "Study on the oxidation process of cobalt hydroxide to cobalt oxides at low temperatures." RSC Advances 6, no. 83 (2016): 80059–64. http://dx.doi.org/10.1039/c6ra16063h.

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43

Tang, K., A. Ciftja, der van, S. Wilson, and G. Tranell. "Recycling of the rare earth oxides from spent rechargeable batteries using waste metallurgical slags." Journal of Mining and Metallurgy, Section B: Metallurgy 49, no. 2 (2013): 233–36. http://dx.doi.org/10.2298/jmmb120808004t.

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A high temperature process for recycling spent nickel-metal hydride rechargeable batteries has been recently developed at SINTEF/NTNU. The spent battery modules were first frozen with liquid nitrogen for the de-activation and brittle fracture treatment. The broken steel scraps and plastics were then separated by the mechanical classification and magnetic separation. The remaining positive and negative electrodes, together with the polymer separator, were heated to 600-800oC in order to remove the organic components and further separate the Ni-based negative electrode. XRF analyses indicate that the heat-treated materials consist mainly of nickel, rare earth and cobalt oxides. The valuable rare earth oxides were further recovered by the high-temperature slagging treatment. The waste metallurgical slags, consist mainly of SiO2 and CaO, were used as the rare earth oxide absorbent. After the high temperature slagging treatment, over 98% of nickel and cobalt oxides were reduced to the metal phase; meanwhile almost all rare earth oxides remain in the molten slags. Furthermore, EPMA and XRF analyses of the slag samples indicate that the rare earth oxides selectively precipitate in the forms of solid xSiO2?yCaO?zRe2O3. The matrix of slag phase is Re2O3 deficient, typically being less than 5 wt%. This provides a sound basis to further develop the high-temperature process of concentrating the Re2O3 oxides in slags.
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44

Tang, Tianmi, Qiaoqiao Zhang, Xue Bai, Zhenlu Wang, and Jingqi Guan. "Enhanced oxygen evolution activity on mesoporous cobalt–iron oxides." Chemical Communications 57, no. 89 (2021): 11843–46. http://dx.doi.org/10.1039/d1cc04178a.

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The excellent OER performance of mesoporous cobalt–iron oxides can be due to concerted catalysis between the iron and cobalt sites that lowers the OER energy barrier, and the large specific surface area providing enough active sites.
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45

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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46

Zhang, Lei, Sha Xiangling, Zhang Lei, Huibin He, Yusu Wang, Zhenhua Ma, and Yonghui Li. "Study on the Desulfurization Performance of N-Type and P-Type Semiconductor Pyrolysis Char Composite Catalyst." Journal of Environmental Science and Management 20, no. 1 (June 30, 2017): 10–17. http://dx.doi.org/10.47125/jesam/2017_1/02.

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Ordos coal pyrolysis product roasted under 750oC was used as desulfurization sorbents to investigate the effect of flue gas desulfurization performance of supported metal catalyst. There were 14 kinds of metal oxides from groups IA, IIA, VIB, VIIB, VIII, IB and IIIB chosen as active components to prepare metal oxide supported catalysts by equivalent volume impregnation method. And the mechanism of pyrolysis was studied. The similarities of desulfurization performance among the same group of metal oxides were related to the structure of their outer electrons. In addtion, the influence of transition metal oxides on the desulfurization performance was related to metal oxide semiconductor type. Finally, the influence of the VIII group oxide catalyst of iron (Fe), Cobalt (Co), Nickel (Ni) on the desulfurization performance showed the characteristics of diversity related to their d percentage (%).
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47

Dedov, A. G., O. A. Slyakhtin, A. S. Loktev, G. N. Mazo, S. A. Malyshev, and I. I. Moiseev. "New metal-oxide composite materials as efficient catalysts of the partial oxidation of methane." Доклады Академии наук 484, no. 3 (April 15, 2019): 299–302. http://dx.doi.org/10.31857/s0869-56524843299-302.

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Single-phase complex oxides Nd2-yCayCoxNi1-xO4 have been synthesized for the first time. Composites prepared by the reduction of these compounds with hydrogen and containing Nd2O3, CaO, and cobalt and nickels metals have been used for the first time as catalysts of the partial oxidation of methane. The maximal methane conversions (97%) and syngas yields (96%) at 900 °С have been detected in the presence of the composite obtained from Nd1,5Ca0,5NiO4. At T < 850 °C, the nickel–cobalt composite synthesized from Nd1,3Ca0,7Co0,4Ni0,6O4 turned out to be more selective in the formation of syngas. Decreasing the partial oxidation temperature from 900 °С to 750 °С leads to the oxidation of metallic nickel and cobalt to oxides and to partial resynthesis of complex oxides with perovskite and K2NiF4 structures. The observed differences in temperature dependence of the catalytic properties of composites with various Ni/Co ratios can be associated with the participation of complex oxides in catalysis of the partial oxidation of methane at low temperatures.
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48

Abdel-Mohsen, Fawzia Fahim, and Hassan Salah Aly Emira. "Spectrally selective nano-absorber pigments." Pigment & Resin Technology 44, no. 6 (November 2, 2015): 347–57. http://dx.doi.org/10.1108/prt-08-2014-0065.

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Purpose – The purpose of this study was to prepare colour pigments for use as spectrally selective coatings for solar absorbers. Design/methodology/approach – Nano-particles cobalt and nickel oxides were prepared by sol–gel techniques. These oxides were prepared with its molar ratios and annealed at 200, 400, 600 and 800°C. The structure of the pigments was characterized by infrared spectrometer, differential scanning calorimetry analysis, X-ray diffraction, transmission electron microscope and scanning electron microscope. Findings – Encapsulated cobalt and nickel oxides were completely formed at 800 and 600°C, and its colour was black and dark green, respectively. The results confirmed that black and green pigments combined selectivity with colour. Optical properties such as absorption and reflection were affected by the firing temperatures on cobalt and nickel oxides–gel polymers. All synthesized pigments consisted of nano-particles. Research limitations/implications – The prepared samples used in the present work were synthesized from cobalt chloride and nickel acetate. The salts were dispersed in polyacrylamide as a precursor. Practical implications – The prepared metal oxides had good solar properties. Originality/value – Colour becomes more important for thermal solar collectors, and it has attracted interest. This might be related to a generally growing attention towards architectural integration of solar energy systems into building. Architects would prefer different colours besides black, even if lower efficiency would have to be accepted.
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49

Haniam, P., C. Kunsombat, S. Chiangga, and A. Songsasen. "Synthesis of Cobalt Oxides Thin Films Fractal Structures by Laser Chemical Vapor Deposition." Scientific World Journal 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/685270.

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Thin films of cobalt oxides (CoO and Co3O4) fractal structures have been synthesized by using laser chemical vapor deposition at room temperature and atmospheric pressure. Various factors which affect the density and crystallization of cobalt oxides fractal shapes have been examined. We show that the fractal structures can be described by diffusion-limited aggregation model and discuss a new possibility to control the fractal structures.
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50

Chen, Jianmeng, Junhong Lin, Jinghuan Chen, and Jiade Wang. "Effect of Small Molecular Organic Acids on the Structure and Catalytic Performance of Sol–Gel Prepared Cobalt Cerium Oxides towards Toluene Combustion." Catalysts 9, no. 5 (May 24, 2019): 483. http://dx.doi.org/10.3390/catal9050483.

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Cobalt cerium oxide catalysts with small molecular organic acids (SOAs) as chelating agents were prepared via the sol–gel method and investigated for the complete oxidation of toluene. Four kinds of natural SOAs, i.e. malic acid (MA), citric acid (CA), glycolic acid (GA), and tartaric acid (TA), were selected. The effect of organic acids on the composition, structure, morphology and catalytic performance of metal oxides is discussed in details. The cobalt cerium oxides catalysts were characterized by various techniques, including TG–DSC, XRD, SEM–EDS, N2–adsorption and desorption, XPS, and H2–TPR analyses. The results show that the nature of organic acids influenced the hydrolysis, condensation and calcination processes, as well as strongly affected the textural and physicochemical properties of the metal oxides synthesized. The best catalytic activity was obtained with the CoCe–MA catalyst, and the toluene conversion reached 90% at 242 °C. This outstanding catalytic activity could be related to its textural, redox properties and unique surface compositions and oxidation states. In addition, the CoCe–MA catalyst also showed excellent stability in long–time activity test.
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