Topic
Cobalt
About: Cobalt is a research topic. Over the lifetime, 69899 publications have been published within this topic receiving 1242058 citations. The topic is also known as: Co & Element 27.
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TL;DR: Smith et al. as mentioned in this paper used a hindered, rigid bidentate ligand (L) to create 12-electron methyliron(II) and 13-electronic methylcobalt(II), and showed that the ligand is thermally stable and low coordination number is maintained in solution.
Abstract: Three-coordinate organometallic complexes are rare, especially with the prototypical methyl ligand. Using a hindered, rigid bidentate ligand (L), it is possible to create 12-electron methyliron(II) and 13-electron methylcobalt(II) complexes. These complexes are thermally stable, and (1)H NMR spectra suggest that the low coordination number is maintained in solution. Attempts to create the 14-electron LNiCH(3) led instead to the three-coordinate nickel(I) complex LNi(THF). Single crystals of LMCH(3) are isomorphous with the new three-coordinate chloride complexes LNiCl and LCoCl. Along with the recently reported LFeCl (Smith, J. M.; Lachicotte, R. J.; Holland, P. L. Chem. Commun. 2001, 1542), these are the only examples of three-coordinate iron(II), cobalt(II), and nickel(II) complexes with terminal chloride ligands, enabling the systematic evaluation of the effect of coordination number and metal identity on M-Cl bond lengths. Electronic structure calculations predict the ground states of the trigonal complexes.
176 citations
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TL;DR: In this paper, the authors reported the heterogeneous catalytic degradation and mineralization of phenol in aqueous solution by means of potassium monopersulfate (PMS or Oxone) process mediated by cobalt perovskite-based catalysts (P-Co).
Abstract: This study reports the heterogeneous catalytic degradation and mineralization of phenol in aqueous solution by means of potassium monopersulfate (PMS or Oxone) process mediated by cobalt perovskite-based catalysts (P-Co). Four nanostructured perovskites oxides with formula ACoO3 (A = Ba, Ce, La, Sr) were synthesized as heterogeneous catalysts by the citrate sol gel method and characterized by means of nitrogen isotherm adsorption (BET), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDX), x-ray photoelectron spectroscopy (XPS), X-ray Diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) techniques. All the examined samples had perovskite structure. The influences of PMS dosage, catalyst loading, initial target compound concentration and solution pH on the removal efficiency were studied. The activity showed an order of SrCoO3 > LaCoO3 > BaCoO3 > CeCoO3. LaCoO3 and SrCoO3 catalysts exhibit the better performance in terms of reaction rate and stability for the phenol degradation and mineralization by advanced oxidation technology based on sulfate radicals. Catalyst stability was assessed by means of consecutive reuse cycles. No significant loss of activity was noticed after five consecutive cycles. The role of reactive oxygen species produced in the system, mainly SO4 − and OH, in the overall oxidation of phenol was determined by using suitable scavenger compounds. Under optimal conditions (10−4 M PMS, natural pH, 0.3 gL−1 catalyst loading) complete removal of 20 mgL−1 phenol was achieved in 90 min. In terms of organic carbon removal, about 81% mineralization yield was reached in the optimal conditions for 6 h heterogeneous P-Co/PMS system, suggesting an effective process for phenol mineralization. Four organics intermediates were observed and three of them were identified as catechol, hydroquinone and benzoquinone. A reaction sequence was therefore proposed for the degradation according to the detected products. Subsequent attack of these intermediates by SO4 − radicals led to the formation of short chain acids such as, acetic, formic and oxalic acid which were identified by ion-exclusion chromatography.
176 citations
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01 Jan 1991
TL;DR: Groups 3-5. Scandium to Tantalum (D. Rehder), Group 6. Manganese to Rhenium (P.S. Pregosin), Group 7. Iron to Osmium (R. Benn), Group 8. Cobalt and Rhodium (B.E. Mann), Group 9. Nickel to Platinum (PregosIN), Group 10. Granger, Group 11 and 12.
Abstract: Groups 3-5. Scandium to Tantalum (D. Rehder). Group 6. Chromium to Tungsten (C. Brevard, P.S. Pregosin and R. Thouvenot). Group 7. Manganese to Rhenium (P.S. Pregosin). Group 8. Iron to Osmium (R. Benn). Group 9. Cobalt and Rhodium (B.E. Mann and P.S. Pregosin). Group 10. Nickel to Platinum (P.S. Pregosin). Groups 11 and 12. Copper to Mercury (P. Granger). Index.
176 citations
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TL;DR: In this article, the authors investigated the process of photocatalytic hydrogen production from glycerol aqueous solution, with the use of cobalt doped TiO2 photocatalyst under solar light irradiation.
175 citations
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TL;DR: A solvent extraction process with the ionic liquid trihexyl(tetradecyl)phosphonium nitrate has been developed to extract rare earths and separate them from nickel or cobalt as discussed by the authors.
175 citations