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: In this article, the catalytic capacity of Co-BNNS is attributed to the strong mixing between the cobalt 3d orbitals and oxygen 2p orbitals, which activates the adsorbed molecular or atomic oxygen.
Abstract: By means of first-principles computation, metal (Cu, Ag, Au, Pt, Rh, Pd, Fe, Co, and Ir) doped hexagonal boron nitride nanosheets (h-BNNSs) have been systematically investigated. The strong interaction between the metal atoms and defect sites in h-BNNS, such as the boron vacancy and nitrogen edge, suggests that metal doped h-BN nanosheets (M-BNNSs) should be stable under high temperatures. The catalytic activity of Co doped h-BNNS is also investigated by using CO oxidation as a probe, and the calculated low barrier suggests that the Co-BNNS is a viable catalyst for CO oxidation. Based on electronic structure analysis, the catalytic capacity of Co-BNNS is attributed to the strong mixing between the cobalt 3d orbitals and oxygen 2p orbitals, which activates the adsorbed molecular or atomic oxygen.
303 citations
TL;DR: In this paper, the authors investigated the role of oxygen and manganese in the redox process in charge and showed that oxygen is significantly more involved in the reduction process than O2.
Abstract: Materials prepared by chemical Li deintercalation with NO2BF4 from Li1.20Mn0.54Co0.13Ni0.13O2 and chemical Li reinsertion with LiI show very similar chemical composition, oxidation state of each transition metal ion, structural properties and electrochemical performance to those of the material recovered after the 1st electrochemical cycle. Investigations combining redox titration, magnetic measurement, neutron diffraction and chemical analyzes reveal that uncommon redox processes are involved during the first charge at high voltage and explain the charge overcapacity and large reversible discharge capacity obtained for this material. This further assesses our proposal that oxygen, in addition to nickel and cobalt, participates to the redox processes in charge: within the bulk oxygen is oxidized without oxygen loss, whereas at the surface oxygen is oxidized to O2 and irreversibly lost from the structure. During the subsequent discharge, in addition to nickel, cobalt and oxygen, manganese is also slightly involved in the redox processes (reduction) to compensate for the initial surface oxygen loss.
303 citations
TL;DR: An environmentally friendly process for the separation of the transition metals copper, cobalt, iron, manganese and zinc from rare earths by solvent extraction with the ionic liquid trihexyl(tetradecyl)phosphonium chloride has been developed as discussed by the authors.
302 citations
TL;DR: This work utilizes Raman spectroscopy and X-ray absorptionSpectroscopy as a tool to elucidate the structure and function of an amorphous cobalt sulfide (CoSx) catalyst and surmise that these CoS2-like clusters form under cathodic polarization and expose a high density of catalytically active sulfur sites for the HER.
Abstract: The generation of chemical fuel in the form of molecular H2 via the electrolysis of water is regarded to be a promising approach to convert incident solar power into an energy storage medium. Highly efficient and cost-effective catalysts are required to make such an approach practical on a large scale. Recently, a number of amorphous hydrogen evolution reaction (HER) catalysts have emerged that show promise in terms of scalability and reactivity, yet remain poorly understood. In this work, we utilize Raman spectroscopy and X-ray absorption spectroscopy (XAS) as a tool to elucidate the structure and function of an amorphous cobalt sulfide (CoSx) catalyst. Ex situ measurements reveal that the as-deposited CoSx catalyst is composed of small clusters in which the cobalt is surrounded by both sulfur and oxygen. Operando experiments, performed while the CoSx is catalyzing the HER, yield a molecular model in which cobalt is in an octahedral CoS2-like state where the cobalt center is predominantly surrounded by a first shell of sulfur atoms, which, in turn, are preferentially exposed to electrolyte relative to bulk CoS2. We surmise that these CoS2-like clusters form under cathodic polarization and expose a high density of catalytically active sulfur sites for the HER.
302 citations
TL;DR: A novel process involving vacuum pyrolysis and hydrometallurgical technique was developed for the combined recovery of cobalt and lithium from spent lithium-ion batteries and showed that the cathode powder composing of LiCoO(2) and CoO peeled completely from aluminum foils.
301 citations