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Journal articles on the topic 'Cobalt activation'

Author: Grafiati

Published: 4 June 2021

Last updated: 20 February 2023

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1

Mao, Po-Hsin, Ta Cong Khiem, Eilhann Kwon, Hou-Chien Chang, Ha Manh Bui, Xiaoguang Duan, Hongta Yang, et al. "Ambient-Visible-Light-Mediated Enhanced Degradation of UV Stabilizer Bis(4-hydroxyphenyl)methanone by Nanosheet-Assembled Cobalt Titanium Oxide: A Comparative and DFT-Assisted Investigation." Water 14, no. 20 (October 20, 2022): 3318. http://dx.doi.org/10.3390/w14203318.

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Bis(4-hydroxyphenyl)methanone (BHPM), a common ultraviolet stabilizer and filter (USF), is extensively added in sunscreens; however, BHPM is proven as an endocrine disruptor, posing a serious threat to aquatic ecology, and BHPM should be then removed. As sulfate radical (SO4•−) could be useful for eliminating emerging contaminants, oxone appears as a favorable source reagent of SO4•− for degrading BHPM. Even though cobalt is a useful catalyst for activating oxone to generate SO4•−, it would be even more promising to utilize ambient-visible-light irradiation to enhance oxone activation using cobaltic catalysts. Therefore, in contrast to the conventional cobalt oxide, cobalt titanium oxide (CTO) was investigated for chemical and photocatalytic activation of oxone to eliminate BHPM from water. Especially, a special morphology of nanosheet-assembled configuration of CTO was designed to maximize active surfaces and sites of CTO. Thus, CTO outperforms Co3O4 and TiO2 in degrading BHPM via oxone activation. Furthermore, the substituent of Ti enabled CTO to enhance absorption of visible light and possessed a much smaller Eg. These photocatalytic properties intensified CTO’s activity for oxone activation. CTO possessed a significantly smaller Ea of degradation of USFs than other catalytic systems. Mechanistic insight for degrading BHPM by CTO + oxone was explicated for identifying contribution of reactive oxygen species to BHPM degradation. The BHPM degradation pathway was also investigated and unveiled in details via the DFT calculation. These results validated that CTO is a superior cobaltic alternative for activating oxone to eliminate BHPM.

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2

Moselage, Marc, Jie Li, and Lutz Ackermann. "Cobalt-Catalyzed C–H Activation." ACS Catalysis 6, no. 2 (December 21, 2015): 498–525. http://dx.doi.org/10.1021/acscatal.5b02344.

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3

Volla, Chandra M. R., Rahul K. Shukla, and Akshay M. Nair. "Allenes: Versatile Building Blocks in Cobalt-Catalyzed C–H Activation." Synlett 32, no. 12 (March 31, 2021): 1169–78. http://dx.doi.org/10.1055/a-1471-7307.

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AbstractThe unique reactivity of allenes has led to their emergence as valuable coupling partners in transition-metal-mediated C–H activation reactions. On the other hand, due to its high abundance and high Lewis acidity, cobalt is garnering widespread interest as a useful catalyst for C–H activation. Here, we summarize cobalt-catalyzed C–H activations involving allenes as coupling partners and then describe our studies on Co(III)-catalyzed C-8 dienylation of quinoline N-oxides with allenes bearing a leaving group at the α-position for realizing a dienylation protocol.

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4

Rytter, Erling, Christian Aaserud, Anne-Mette Hilmen, Edvard Bergene, and Anders Holmen. "Activation of Cobalt Foil Catalysts for CO Hydrogenation." Catalysts 12, no. 1 (January 8, 2022): 65. http://dx.doi.org/10.3390/catal12010065.

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CO hydrogenation has been studied on cobalt foils as model catalysts for Fischer–Tropsch (FT) synthesis. The effect of pretreatment (number of calcinations and different reduction times) for cobalt foil catalysts at 220 °C, 1 bar, and H2/CO = 3 has been studied in a microreactor. The foils were examined by scanning electron microscopy (SEM). It was found that the catalytic activity of the cobalt foil increases with the number of pretreatments. The mechanism is likely an increase in the available cobalt surface area from progressively deeper oxidation of the foil, supported by surface roughness detected by SEM. The highest FT activity was obtained using a reduction time of only 5 min (compared to 1 and 30 min). Prolonged reduction caused the sintering of cobalt crystallites, while too short of a reduction time led to incomplete reduction and small crystallites susceptible to low turn-over frequency from structure sensitivity. Larger crystals from longer reduction times gave increased selectivity to heavier components. The paraffin/olefin ratio increased with the increasing number of pretreatments due to olefin hydrogenation favored by enhanced cobalt site density. From the results, it is suggested that olefin hydrogenation is not structure sensitive, and that mass transfer limitations may occur depending on the pretreatment procedure. Produced water did not influence the results for the low conversions experienced in the present study (<6%).

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5

Santhoshkumar, Rajagopal, and Chien-Hong Cheng. "Hydroarylations by cobalt-catalyzed C–H activation." Beilstein Journal of Organic Chemistry 14 (August 29, 2018): 2266–88. http://dx.doi.org/10.3762/bjoc.14.202.

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As an earth-abundant first-row transition metal, cobalt catalysts offer a broad range of economical methods for organic transformations via C–H activation. One of the transformations is the addition of C–H to C–X multiple bonds to afford alkylation, alkenation, amidation, and cyclization products using low- or high-valent cobalt catalysts. This hydroarylation is an efficient approach to build new C–C bonds in a 100% atom-economical manner. In this review, the recent developments of Co-catalyzed hydroarylation reactions and their mechanistic studies are summarized.

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6

Zirngast, Michaela, Christoph Marschner, and Judith Baumgartner. "Cobalt-Assisted Silicon−Silicon Bond Activation." Organometallics 25, no. 20 (September 2006): 4897–908. http://dx.doi.org/10.1021/om0604831.

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7

Sauermann, Nicolas, Tjark H. Meyer, and Lutz Ackermann. "Electrochemical Cobalt-Catalyzed C−H Activation." Chemistry - A European Journal 24, no. 61 (August 2, 2018): 16209–17. http://dx.doi.org/10.1002/chem.201802706.

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8

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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9

Stuchlý, V., H. Zahradníková, and L. Beránek. "Activation of a hydrorefining cobalt—molybdenum catalyst." Applied Catalysis 35, no. 1 (November 1987): 23–34. http://dx.doi.org/10.1016/s0166-9834(00)82420-3.

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10

Stuchlý, V., and L. Beránek. "Activation of a hydrorefining cobalt—molybdenum catalyst." Applied Catalysis 35, no. 1 (November 1987): 35–45. http://dx.doi.org/10.1016/s0166-9834(00)82421-5.

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11

Moselage, Marc, Jie Li, and Lutz Ackermann. "ChemInform Abstract: Cobalt-Catalyzed C-H Activation." ChemInform 47, no. 15 (March 2016): no. http://dx.doi.org/10.1002/chin.201615217.

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12

Rudd, P. Alex, Nora Planas, Eckhard Bill, Laura Gagliardi, and Connie C. Lu. "Dinitrogen Activation at Iron and Cobalt Metallalumatranes." European Journal of Inorganic Chemistry 2013, no. 22-23 (July 4, 2013): 3898–906. http://dx.doi.org/10.1002/ejic.201300272.

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13

L. V. Spivak and N.E. Shchepina. "Features of polymorphic transformation during heating and cooling of cobalt." Technical Physics 92, no. 4 (2022): 478. http://dx.doi.org/10.21883/tp.2022.04.53604.295-21.

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Differential scanning calorimetry was used to study the regularities of polymorphic α↔β-transformation in polycrystalline cobalt. The value of the activation energy of the α->β-transformation during heating of cobalt (290-50 kJ/mol), enthalpy and entropy, depending on the thermal history of the metal, is determined. It is shown that the mechanisms of recrystallization under heating are closer to the first-order I phase transformations. When cooling under conditions of limited diffusion mobility of cobalt atoms, recrystallization is apparently carried out due to the passage of several diffusion-free mechanisms of phase transformation, implemented in close temperature ranges. Keywords: activation energy, cobalt, calorimetry, polymorphism, enthalpy, entropy.

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14

Rao, Ramya R., and Catherine L. Lawson. "Structure of catabolite activator protein with cobalt(II) and sulfate." Acta Crystallographica Section F Structural Biology Communications 70, no. 5 (April 15, 2014): 560–63. http://dx.doi.org/10.1107/s2053230x14005366.

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The crystal structure of cyclic AMP–catabolite activator protein (CAP) fromEscherichia colicontaining cobalt(II) chloride and ammonium sulfate is reported at 1.97 Å resolution. Each of the two CAP subunits in the asymmetric unit binds one cobalt(II) ion, in each case coordinated by N-terminal domain residues His19, His21 and Glu96 plus an additional acidic residue contributedviaa crystal contact. The three identified N-terminal domain cobalt-binding residues are part of a region of CAP that is important for transcription activation at class II CAP-dependent promoters. Sulfate anions mediate additional crystal lattice contacts and occupy sites corresponding to DNA backbone phosphate positions in CAP–DNA complex structures.

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15

Elferink, J. G., and M. Deierkauf. "Suppressive action of cobalt on exocytosis and respiratory burst in neutrophils." American Journal of Physiology-Cell Physiology 257, no. 5 (November 1, 1989): C859—C864. http://dx.doi.org/10.1152/ajpcell.1989.257.5.c859.

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Activation of exocytosis and respiratory burst in rabbit neutrophils by the chemotactic peptide fMet-Leu-Phe is inhibited by Co2+. Inhibition is antagonized by extracellular Ca2+ and is dependent on the time of preincubation of cells with Co2+ before addition of activator. Co2+ inhibits the enhancement of 45Ca association that occurs during activation with fMet-Leu-Phe. Interference with Ca2+ translocation across the plasma membrane by Co2+ is probably not the cause of inhibition of neutrophil activation, because activation in the absence of extracellular Ca2+ is inhibited by Co2+. Activation of neutrophils by phorbol myristate acetate is inhibited at higher Co2+ concentrations than activation by fMet-Leu-Phe. Inhibition of the superoxide production by Co2+ occurs both in the presence or in the absence of cytochalasin B. Fluorescence of neutrophils loaded with quin2 is diminished by Co2+, indicating that Co2+ had entered into the cytoplasm. The results are compatible with the view that Co2+ inhibits exocytosis and respiratory burst in neutrophils by an interaction with a Ca2+-dependent intracellular target.

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16

Gu, Shuaijie, Jingying Cui, Fangqin Liu, and Jinyang Chen. "Biochar loaded with cobalt ferrate activated persulfate to degrade naphthalene." RSC Advances 13, no. 8 (2023): 5283–92. http://dx.doi.org/10.1039/d2ra08120b.

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Considering the simple preparation of biochar and the excellent activation performance of cobalt ferrate material, a biochar supported cobalt ferrate composite was synthesized by a solvothermal method.

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17

Denisova, Kristina, Alexander A. Ilyin, Ruslan Rumyantsev, Julia Sakharova, Alexander P. Ilyin, and Natalya Gordina. "Low-Temperature Synthesis and Catalytic Activity of Cobalt Ferrite in Nitrous Oxide (N2O) Decomposition Reaction." Catalysts 11, no. 8 (July 22, 2021): 889. http://dx.doi.org/10.3390/catal11080889.

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Cobalt ferrite (CoFe2O4) nanoparticles were synthesized and investigated as a catalyst in the reaction of nitrous oxide (N2O) decomposition. Cobalt ferrite was synthesized by solid–phase interaction at 1100 °C and by preliminary mechanochemical activation in a roller-ring vibrating mill at 400 °C. The nanoparticles were characterized by X-ray diffraction (XRD), synchronous thermal analysis (TG and DSC) and scanning electron microscopy (SEM). A low-temperature nitrogen adsorption/desorption test was used to evaluate the catalytic activity of the cobalt ferrite nanoparticles. Correlations between the structure and catalytic properties of the catalysts are reported. The highest catalytic activity of CoFe2O4 in the reaction of nitrous oxide decomposition was 98.1% at 475 °C for cobalt ferrite obtained by mechanochemical activation.

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18

Haysak, Ivan, Vasyl Martishichkin, Yevgen Harapko, Robert Holomb, and Karel Katovsky. "Production and Monitoring of Neutron Flux by Activation Detectors." EPJ Web of Conferences 253 (2021): 01005. http://dx.doi.org/10.1051/epjconf/202125301005.

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The neutron generation technique was tested on the microtron M-10 with an output electron beam of 8.7 MeV. Given the low energy that the microtron can provide to electrons, the bremsstrahlung induced photonuclear reaction 9Be (γ, n), which has a low threshold, was chosen for neutron generation. Cobalt and indium targets were tested as activation detectors to estimate the neutron flux density. In the cobalt target, the isomeric state of 60mCo with an energy of 58.6 keV and a half-life of 10.5 minutes is well activated. Two well-known additional gamma lines of standard cobalt source permit to clarify the absolute value of the neutron flux. The activated indium target has four gamma lines bound to the 116mIn isomer β- decaying with the half-life of 54.4 minutes, what is convenient for measurement of gamma spectrum. Despite the low energy of the output electron beam, at a beam intensity of 5 μA it is possible to obtain an almost isotropic neutron flux of 107 n/(s∙cm2).

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19

Fachinetti, G. P., F. Del Cima, Q. Sbrana, and T. Funaioli. "Dihydrogen activation promoted by homonuclear ion pairs involving cobalt(II) and cobalt(−I)." Journal of Organometallic Chemistry 287, no. 1 (May 1985): c23—c24. http://dx.doi.org/10.1016/0022-328x(85)80082-6.

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20

Pashazadeh, Rahim, Saideh Rajai-Daryasarei, Siyavash Mirzaei, Mehdi Soheilizad, Samira Ansari, and Meisam Shabanian. "A Regioselective Approach to C3-Aroylcoumarins via Cobalt-Catalyzed C(sp2)–H Activation Carbonylation of Coumarins." Synthesis 51, no. 15 (April 2, 2019): 3014–20. http://dx.doi.org/10.1055/s-0037-1610702.

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A new cobalt-catalyzed C–H bond activation of coumarins with aryl halides or pseudohalides and carbon monoxide insertion to give various 3-aroylcoumarin derivatives is described. It is the first time that CO as C1 feedstock is used as the coupling partners in cobalt-catalyzed regioselective coumarin C–H functionalization reactions. Upon activation with manganese powder, the Co catalyzes the C–H bond activation carbonylation reactions of aryl iodides, bromides, and even triflates under mild conditions, providing the regioselective aroylated products in moderate to good yields.

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21

Ptitsyna, C. O., A. A. Ilyin, R. N. Rumyantsev, and Y. N. Sakharova. "MECHANOCHEMICAL AND CERAMIC SYNTHESIS OF COBALT FERRITE." Steklo i Keramika, no. 1 (January 2022): 21–30. http://dx.doi.org/10.14489/glc.2022.01.pp.021-030.

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In this work we studied the effect of mechanochemical activation on the formation of the cobalt ferrite phase from iron and cobalt oxalates. X-ray phase, X-ray diffraction and synchronous thermal analysis, scanning electron microscopy, low-temperature nitrogen adsorption-desorption method were used to study the composition and properties of the resulting product. It has been established that cobalt ferrite is formed at a temperature of 1100 °C during solid-phase interaction of the initial components, and the use of mechanochemical activation of the initial components in a roller-ring vibration mill makes it possible to reduce the synthesis temperature to 400 °C. It is shown that CoFe2O4 obtained using the method of mechanochemical synthesis has a more developed specific surface area and porous structure in comparison with cobalt ferrite obtained by the ceramic method.

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22

Saeki, Ryusei, and Takeshi Ohgai. "Determination of Activation Overpotential during the Nucleation of Hcp-Cobalt Nanowires Synthesized by Potentio-Static Electrochemical Reduction." Materials 11, no. 12 (November 22, 2018): 2355. http://dx.doi.org/10.3390/ma11122355.

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The crystal growth process and ferromagnetic properties of electrodeposited cobalt nanowires were investigated by controlling the bath temperature and cathodic overpotential. The cathodic overpotential during electrodeposition of cobalt nanowire arrays, ΔEcath, was theoretically estimated by the difference between the cathode potential, Ecath, and the equilibrium potential, Eeq, calculated by the Nernst equation. On the other hand, the activation overpotential, ΔEact, was experimentally determined by the Arrhenius plot on the growth rate of cobalt nanowire arrays, Rg, versus (vs.) reciprocal temperature, 1/T. The ferromagnetic cobalt nanowire arrays with a diameter of circa (ca.) 25 nm had the preferred crystal orientation of (100) and the aspect ratio reached up to ca. 1800. The average crystal grain size, Ds, of (100) peaks was estimated by X-ray diffraction patterns and was increased by decreasing the cathodic overpotential for cobalt electrodeposition by shifting the cathode potential in the noble direction. Axial magnetization performance was observed in the cobalt nanowire arrays. With increasing Ds, coercivity of the film increased and reached up to ca. 1.88 kOe.

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23

Ujwaldev, Sankuviruthiyil M., Nissy Ann Harry, Mathiyazhagan Arun Divakar, and Gopinathan Anilkumar. "Cobalt-catalyzed C–H activation: recent progress in heterocyclic chemistry." Catalysis Science & Technology 8, no. 23 (2018): 5983–6018. http://dx.doi.org/10.1039/c8cy01418c.

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24

Hall, Matthew D., Timothy W. Failes, Natsuho Yamamoto, and Trevor W. Hambley. "Bioreductive activation and drug chaperoning in cobalt pharmaceuticals." Dalton Transactions, no. 36 (2007): 3983. http://dx.doi.org/10.1039/b707121c.

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25

Zhu, Yunqing, Shuo Chen, Xie Quan, and Yaobin Zhang. "Cobalt implanted TiO2nanocatalyst for heterogeneous activation of peroxymonosulfate." RSC Adv. 3, no. 2 (2013): 520–25. http://dx.doi.org/10.1039/c2ra22039c.

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26

de la Peña O’Shea, Víctor A., Silvia González, Francesc Illas, and José L. G. Fierro. "Evidence for spontaneous CO2 activation on cobalt surfaces." Chemical Physics Letters 454, no. 4-6 (March 2008): 262–68. http://dx.doi.org/10.1016/j.cplett.2008.02.004.

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27

Pino, Piero, Arpad Major, Felix Spindler, Rina Tannenbaum, György Bor, Istaván, and T. Horváth. "Activation of molecular hydrogen in cobalt-catalyzed hydroformylation." Journal of Organometallic Chemistry 417, no. 1-2 (October 1991): 65–76. http://dx.doi.org/10.1016/0022-328x(91)80161-c.

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28

Dufresne, P., N. Brahma, F. Labruyère, M. Lacroix, and M. Breysse. "Activation of off site presulfided CobaltMolybdenum catalysts." Catalysis Today 29, no. 1-4 (May 1996): 251–54. http://dx.doi.org/10.1016/0920-5861(95)00280-4.

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29

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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30

Dinh, Van-Phuc, Ngoc-Chung Le, Ngoc-Tuan Nguyen, Quang-Thien Tran, Van-Dong Nguyen, Anh-Tuyen Luu, N. Quang Hung, Tran Duy Tap, and Thien-Hoang Ho. "Determination of Cobalt in Seawater Using Neutron Activation Analysis after Preconcentration by Adsorption onto γ-MnO2 Nanomaterial." Journal of Chemistry 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/9126491.

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The γ-MnO2 nanomaterial has been used to adsorb cobalt in the seawater at Phan Thiet City, Binh Thuan Province, Vietnam. Its concentration is determined by using the neutron activation analysis (NAA) method at the Dalat nuclear research reactor. Factors affecting the uptake of cobalt on the γ-MnO2 material such as the pH, adsorption time, and initial cobalt(II) concentration are investigated. The irradiated experiment data are calculated using the K0-Dalat program. The results obtained show that the trace dissolved cobalt in Phan Thiet seawater is found equal to 0.25 ± 0.04 μg/L (n=5, P=95%) with the adsorption efficiency being higher than 95% (n=4, P=95%).

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31

Lantcev, Eugeniy, Aleksey Nokhrin, Nataliya Malekhonova, Maksim Boldin, Vladimir Chuvil'deev, Yuriy Blagoveshchenskiy, Nataliya Isaeva, Pavel Andreev, Kseniya Smetanina, and Artem Murashov. "A Study of the Impact of Graphite on the Kinetics of SPS in Nano- and Submicron WC-10%Co Powder Compositions." Ceramics 4, no. 2 (June 10, 2021): 331–63. http://dx.doi.org/10.3390/ceramics4020025.

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This study investigates the impact of carbon on the kinetics of the spark plasma sintering (SPS) of nano- and submicron powders WC-10wt.%Co. Carbon, in the form of graphite, was introduced into powders by mixing. The activation energy of solid-phase sintering was determined for the conditions of isothermal and continuous heating. It has been demonstrated that increasing the carbon content leads to a decrease in the fraction of η-phase particles and a shift of the shrinkage curve towards lower heating temperatures. It has been established that increasing the graphite content in nano- and submicron powders has no significant effect on the SPS activation energy for “mid-range” heating temperatures, QS(I). The value of QS(I) is close to the activation energy of grain-boundary diffusion in cobalt. It has been demonstrated that increasing the content of graphite leads to a significant decrease in the SPS activation energy, QS(II), for “higher-range” heating temperatures due to lower concentration of tungsten atoms in cobalt-based γ-phase. It has been established that the sintering kinetics of fine-grained WC-Co hard alloys is limited by the intensity of diffusion creep of cobalt (Coble creep).

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32

Chu, Xiaoxiao, Jihao Jin, Bangrong Ming, Maofu Pang, Xin Yu, Chen-Ho Tung, and Wenguang Wang. "Bimetallic nickel–cobalt hydrides in H2 activation and catalytic proton reduction." Chemical Science 10, no. 3 (2019): 761–67. http://dx.doi.org/10.1039/c8sc04346a.

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33

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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34

NAQVI, S. M. M. R., S. DABIR H. RIZVI, SAJIDA JAMILA, SHABANA RIZVI, S. MOHSIN RAZA, MUSHTAQ AHMED GORMANI, and N. FAROOQI. "ELECTRICAL RESISTIVITY OF COBALT-BORON LQA ALLOYS." Modern Physics Letters B 09, no. 23 (October 10, 1995): 1535–38. http://dx.doi.org/10.1142/s0217984995001534.

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Activation energies determined from Arrhenius plot for cobalt-boron liquid quenched amorphous alloys in the temperature range 40 K < T < 300 K , suggest vacancy and interstitial formation to nucleate crystalline phases in an amorphous matrix preferably at sites where dangling bonds are present. Nucleation of crystallites with preferential tetragonal or orthorhombic structures is a self-evolving process due to catalytic presence of dangling bonds in an amorphous material and that the occurrence of negative activation energies support this evidence.

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35

Malik, Deesha D., Anirban Chandra, Mi Sook Seo, Yong-Min Lee, Erik R. Farquhar, Stefan Mebs, Holger Dau, Kallol Ray, and Wonwoo Nam. "Formation of cobalt–oxygen intermediates by dioxygen activation at a mononuclear nonheme cobalt(ii) center." Dalton Transactions 50, no. 34 (2021): 11889–98. http://dx.doi.org/10.1039/d1dt01996a.

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36

Shigehisa, Hiroki. "Studies on Catalytic Activation of Olefins Using Cobalt Complex." Chemical and Pharmaceutical Bulletin 66, no. 4 (2018): 339–46. http://dx.doi.org/10.1248/cpb.c17-01006.

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37

Wacławek, Stanisław, Vojtech Antoš, Pavel Hrabák, and Miroslav Černík. "Remediation of hexachlorocyclohexanes by cobalt-mediated activation of peroxymonosulfate." Desalination and Water Treatment 57, no. 54 (November 30, 2015): 26274–79. http://dx.doi.org/10.1080/19443994.2015.1119757.

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38

Begouin, Jeanne-Marie, Michael Rivard, and Corinne Gosmini. "Cobalt-catalyzed C–SMe bond activation of heteroaromatic thioethers." Chemical Communications 46, no. 32 (2010): 5972. http://dx.doi.org/10.1039/c0cc01055c.

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39

Kumanto, Mona, Erja-Leena Paukkeri, Riina Nieminen, and Eeva Moilanen. "Cobalt(II) Chloride Modifies the Phenotype of Macrophage Activation." Basic & Clinical Pharmacology & Toxicology 121, no. 2 (May 25, 2017): 98–105. http://dx.doi.org/10.1111/bcpt.12773.

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40

Kapadia, Jyotsna, and Z. R. Turel. "Determination of cobalt by substoichiometric thermal neutron activation analysis." Journal of Radioanalytical and Nuclear Chemistry Letters 126, no. 5 (March 1988): 387–94. http://dx.doi.org/10.1007/bf02165136.

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41

Gosmini, C., J. M. Begouin, and M. Rivard. "Cobalt-Catalyzed C-SMe Bond Activation of Heteroaromatic Thioethers." Synfacts 2010, no. 11 (October 21, 2010): 1297. http://dx.doi.org/10.1055/s-0030-1258726.

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42

Xu, Hongwei, Paul G. Williard, and Wesley H. Bernskoetter. "C–CN Bond Activation of Acetonitrile using Cobalt(I)." Organometallics 31, no. 5 (February 9, 2012): 1588–90. http://dx.doi.org/10.1021/om201270n.

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43

Han, Hong-Yan, Wei-An Xu, Zhi-Rong Lü, Fei Zou, and Sen Li. "Activation and Inactivation of Horseradish Peroxidase by Cobalt Ions." Journal of Biomolecular Structure and Dynamics 26, no. 1 (August 2008): 83–91. http://dx.doi.org/10.1080/07391102.2008.10507226.

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44

Mei, Ruhuai, Uttam Dhawa, Ramesh C. Samanta, Wenbo Ma, Joanna Wencel‐Delord, and Lutz Ackermann. "Cobalt‐Catalyzed Oxidative C−H Activation: Strategies and Concepts." ChemSusChem 13, no. 13 (May 26, 2020): 3306–56. http://dx.doi.org/10.1002/cssc.202000024.

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45

Prakash, Sekar, Ramajayam Kuppusamy, and Chien-Hong Cheng. "Cobalt-Catalyzed Annulation Reactions via C−H Bond Activation." ChemCatChem 10, no. 4 (January 16, 2018): 683–705. http://dx.doi.org/10.1002/cctc.201701559.

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46

Journal, Baghdad Science. "A study of the effect of new cobalt (II) complex and cyclophosphamide drug on (GPT, ALP) activity by using in vivo system." Baghdad Science Journal 12, no. 3 (September 6, 2015): 555–62. http://dx.doi.org/10.21123/bsj.12.3.555-562.

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Abstract:

The present work involved a study the effect of cobalt(II) complex with formula [CoL(H2O)NO3] .4ETOH where L=Nitro [5-(P-nitro phenyl) -4-phenyl-1,2,4 traizole-3-dithiocarbamato hydrazide] aqua. (4) Ethanol and anti-cancer drug - cyclophosphamide on specific activity of two liver enzymes (GPT,ALP) by utilizing an in vivo system in female mice. On the enzymatic level an inhibition in the activity of GPT was noticed in different body organs such as liver, kidney and lung. The inhibition was noticed in both test and cyclophosphamide drug (cp). Mice were treated with three doses of cyclophosphamide (90,180, 250) ?g/ mouse for three days. The same doses were used for the cobalt (II) complex. The liver shows the highest rate of(GPT) inhibition compared to other organs. The ratio was about 90% at three doses of cobalt (II) complex, this ratio was similar to ratio inhibition of cyclophosphamide at the same doses. On the contrary the enzyme ALP showed high activation in different organs such as liver, kidney and lung in both groups, test and cyclophosphamide drug (cp) at the three doses (90, 180, 250) ?g /mouse. The result showed the highest ratio of activation in the kidney comparable with other organs. The maximum activation of cobalt(II) complex was about 1198% at a concentration 180µg/mouse.There are significant differences(P

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Merz, Lukas S., Clemens K. Blasius, Hubert Wadepohl, and Lutz H. Gade. "Square Planar Cobalt(II) Hydride versus T-Shaped Cobalt(I): Structural Characterization and Dihydrogen Activation with PNP–Cobalt Pincer Complexes." Inorganic Chemistry 58, no. 9 (April 19, 2019): 6102–13. http://dx.doi.org/10.1021/acs.inorgchem.9b00384.

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Levy, Naomi, Jennifer S. Shpilman, Hilah C. Honig, Dan T. Major, and Lior Elbaz. "A surprising substituent effect in corroles on the electrochemical activation of oxygen reduction." Chemical Communications 53, no. 96 (2017): 12942–45. http://dx.doi.org/10.1039/c7cc06920k.

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Potter, Matthew E., Cameron P. Ross, Diego Gianolio, Ramon Rios, and Robert Raja. "Cobalt-containing zeolitic imidazole frameworks for C–H activation using visible-light redox photocatalysis." Catalysis Science & Technology 10, no. 21 (2020): 7262–69. http://dx.doi.org/10.1039/d0cy01061h.

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50

Sherson, D., N. Maltbaek, and K. Heydorn. "A dental technician with pulmonary fibrosis: a case of chromium-cobalt alloy pneumoconiosis?" European Respiratory Journal 3, no. 10 (November 1, 1990): 1227–29. http://dx.doi.org/10.1183/09031936.93.03101227.

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A 45 yr old male developed pulmonary fibrosis after 29 yrs of employment as a dental technician. He subsequently developed adenocarcinoma of the lung. Diffuse interstitial fibrosis was seen using light microscopy. Neutron activation analysis of non-neoplastic lung tissue demonstrated high levels of chromium and cobalt suggesting the possibility of a chromium-cobalt alloy pneumoconiosis.

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