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.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: This study is perhaps the first study that documents the heterogeneous activation of peroxymonosulfate with cobalt, the best-known catalyst-activator for this inorganic peroxide.
Abstract: This study explores the potential of heterogeneous activation of Oxone (peroxymonosulfate) in water using cobalt oxides. Two commercially available cobalt oxides, CoO and Co3O4 (CoO·Co2O3) were tested for the activation of peroxymonosulfate and the consequent oxidation of 2,4-dichlorophenol (2,4-DCP) via a sulfate radical mechanism. Both systems, CoO/Oxone and Co3O4/Oxone, were tested at acidic and neutral pH and compared with the homogeneous Co(NO3)2/Oxone. The activity of these systems was evaluated on the basis of the induced transformation of 2,4-DCP as well as the dissolution of cobalt occurred after 2 h of reaction. It was observed that only Co3O4 activates peroxymonosulfate heterogeneously, with its heterogeneity being more pronounced at neutral pH. Both CoO and Co2O3 contained in Co3O4 might be responsible for the observed heterogeneity, and the relative mechanisms are further discussed here. To our knowledge, this is perhaps the first study that documents the heterogeneous activation of peroxymon...
452 citations
••
TL;DR: In this paper, the authors investigated the effect of cobalt on the direct deoxygenation (DDO) pathway involved in guaiacol conversion and showed that in the presence of the CoMoS phase, the DDO pathway was strongly increased as compared to the non-promoted MoS2 phase.
Abstract: Unsupported and alumina-supported MoS2 and CoMoS catalysts have been compared in the hydrodeoxygenation (HDO) reaction of guaiacol (2-methoxyphenol), a typical model molecule for bio-oils coming from the pyrolysis of ligno-cellulosic biomass. The goal of this work was to understand the cobalt promoting effect on MoS2 phase in this type of catalytic reaction. It appeared clearly that in the presence of the CoMoS phase, the direct deoxygenation (DDO) pathway involved in guaiacol conversion was strongly increased as compared to the non-promoted MoS2 in the bulk or supported state. This effect is similar to the well-known increase of direct desulfurization (DDS) pathway by cobalt promoter in the hydrodesulfurization (HDS) of refractory sulfur compounds over molybdenum sulfide catalysts.
451 citations
••
TL;DR: These CoMnP nanoparticles are capable of catalyzing water oxidation at an overpotential of 0.33 V with a 96% Faradaic efficiency when deposited as an ink with carbon black and Nafion and a slight decrease in activity is observed after 500 cycles.
Abstract: The development of efficient water oxidation catalysts based on inexpensive and Earth-abundant materials is a prerequisite to enabling water splitting as a feasible source of alternative energy. In this work, we report the synthesis of ternary cobalt manganese phosphide nanoparticles from the solution-phase reaction of manganese and cobalt carbonyl complexes with trioctylphosphine. The CoMnP nanoparticles (ca. 5 nm in diameter) are nearly monodisperse and homogeneous in nature. These CoMnP nanoparticles are capable of catalyzing water oxidation at an overpotential of 0.33 V with a 96% Faradaic efficiency when deposited as an ink with carbon black and Nafion. A slight decrease in activity is observed after 500 cycles, which is ascribed to the etching of P into solution, as well as the oxidation of the surface of the nanoparticles. Manganese-based ternary phosphides represent a promising new system to explore for water oxidation catalysis.
450 citations
•
13 Dec 2001
TL;DR: A nickel-based super alloy is a monocrystalline structure having an isotropic distribution of the orientation of the grain structure as discussed by the authors, which is a super alloy that contains at least 2 wt.% Re and a maximum of 3 wt% Ru.
Abstract: Component made from a nickel-based super alloy contains (in wt.%) 9-11 chromium (Cr),3-5 tungsten (W), 0.5-2.5 molybdenum (Mo), 3-3.5 aluminium (Al), 3-5 titanium (Ti), 3-7 tantalum (Ta), 0-12 cobalt (Co), 0-1 niobium (Nb), 0-2 hafnium (Hf), 0-1 zirconium (Zr), 0-0.05 boron (B), 0-0.2 carbon (C), 1-5 rhenium (Re), 0.1-5 ruthenium (Ru), balance nickel (Ni) and impurities. Preferably the alloy contains at least 2 wt.% Re and a maximum of 3 wt.% Ru. The component is a monocrystalline structure having an isotropic distribution of the orientation of the grain structure.
448 citations
••
TL;DR: In this article, specific activity and selectivity of unsupported cobalt and cobalt supported on alumina, silica, titania, carbon, and magnesia carriers for CO hydrogenation were measured in a single-pass differential reactor at low conversions, 1 atm, and 175-350 °C.
446 citations