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.

Activated carbon supported cobalt catalysts for advanced oxidation of organic contaminants in aqueous solution

Abstract: A heterogeneous cobalt catalyst was prepared by impregnation of cobalt ion on an activated carbon (AC) and used to activate peroxymonosulphate (PMS) for advanced oxidation of phenol in aqueous solution. The Co/AC catalyst was characterised by several techniques such as XRD, EDS, SEM, and TGA. It was found that Co2O3 was the major form of Co species and was homogeneously distributed on the activated carbon surface. Co/AC exhibited high activity in oxidation of phenol with sulphate radicals and 100% decomposition and 80% TOC removal could be achieved in 60 min at the conditions of 500 ml phenol solution of 25 ppm, 0.1 g catalyst and 1 g peroxymonosulphate. The catalyst also exhibited stable performance after several rounds of regeneration. Several operational parameters such as catalyst and oxidant amount, temperature on the rate of oxidation were found to influence the phenol oxidation.

Electrochemical polymerization of amino-, pyrrole-, and hydroxy-substituted tetraphenylporphyrins

Abstract: are described. Oxidations of these monomers lead to thin polymeric coatings on electrodes by coupling reactions analogous to those operative in polyaniline, polypyrrole, and polyphenol electropolymerization. The films contain from two to several hundred layers of porphyrin sites and display reductive electrochemical and electronic spectroscopic properties similar to those of monomer solutions in acetonitrile or methylene chloride. The pyrtolyl- and amino-based polymers are polycationic and thus anion exchangers, whereas the hydroxy-based polymers (at pH >8) are polyanionic. Films prepared from electropolymerization of cobalt tetrakis(o-aminopheny1)porphyrin display a split Co(III/II) wave in aqueous acid and base and are good oxygen reduction catalysts, whereas films prepared from all other cobalt porphyrin monomers display only one Co(III/II) wave and are poor catalysts.

The Role of Catalysts and Peroxide Oxidation in Lithium–Oxygen Batteries

Abstract: A promotor for lithium batteries: nanocrystalline cobalt(II,III) oxide supported on graphene enhances the transport kinetics for both oxygen reduction and oxygen evolution in the lithium-oxygen cell. On cycling the lithium-oxygen cell, the effect of the promoter is, however, eventually overwhelmed by side reactions in the cell, such as, the deposition of carbonates.

Synthesis of Magnetite/Graphene Oxide Composite and Application for Cobalt(II) Removal

Abstract: A magnetite/graphene oxide (M/GO) composite was synthesized via a chemical reaction with a magnetite particle size of 10–15 nm and was developed for the removal of heavy metal ions from aqueous solutions. The composite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The sorption of Co(II) on the M/GO composite was carried out under various conditions, that is, contact time, sorbent content, pH, ionic strength, foreign ions, and temperature. The sorption isotherms of Co(II) on the M/GO composite could be described well by the Langmuir model. The thermodynamic parameters (ΔH0, ΔS0, and ΔG0) calculated from the temperature-dependent isotherms indicated that the sorption reaction of Co(II) on the M/GO composite was an endothermic and spontaneous process. M/GO can be separated and recovered by magnetic separation. Results show that the magnetic M/GO composite is a promising sorbent material for the preconcentration an...