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CoO/Super P (conductive black) composites (CSP) were synthesized by a facile hydrothermal process followed by a heating treatment. The sample presents a porous CoO nanorod with inserted Super P structure. These CSP composites exhibit superior electrochemical performances in high Li-ion storage capacity (1020 mA h g −1 at 100 mA g −1 ) and rate capability (770 mA h g −1 at 1000 mA g −1 ) during the charge–discharge process. The specific role of Super P was further revealed to mainly accelerate the electrochemical reaction of CoO electrode during Li-ion insertion/extraction process. Thus, it shows much enhanced electrochemical performances compared with pure CoO. [ABSTRACT FROM AUTHOR]

Hierarchical hybrid electrodes CoO@MnO 2 nanosheet@nanosheet arrays (NNAs) for high-performance supercapacitors are designed and grown on a 3D nickel foam by a simple two step solution method combined with a post annealing treatment in Ar gas. The MnO 2 nanosheets can grow directly on the CoO precursor nanosheet arrays without any pretreatment, and its thickness on the CoO NAs can also be tailored by adjusting the hydrothermal time. The NNAs with the elegant synergy between CoO and MnO 2 lead to a highly enhanced areal capacitance (2.40 F cm −2 at 2.0 mA cm −2 , with a wide potential window of 0.8 V). We further fabricated asymmetric supercapacitor device based on the CoO@MnO 2 NNAs and active carbon, which achieved a high-energy density of 1.4 mWh cm −3 at a power density of 9.6 mW cm −3 , a high power density of 192.3 mW cm −3 at 0.7 mWh cm −3 and good cyclic stability. [ABSTRACT FROM AUTHOR]

In this study, we investigated the adsorption behaviors of the Co atom and CoO molecules on the MgO(100) surface, including the diffusion processes based on density functional theory calculations. The structure and growth morphology of the deposited cobalt oxide at various coverage levels as well as the magnetic properties are also discussed. The CoO molecule is found to bind more strongly to the surface compared to the isolated neutral Co atom, which is physically adsorbed on top of the surface oxygen site. Different to the isolated Co atom, the diffusion path of CoO molecule predominantly involves 90° rotation movements about its ends, while the surface hollow site acts as the saddle point for the hopping of the Co atom between two adjacent oxygen sites. A two-dimensional growth mode is observed to be the dominant layer growth mechanism for CoO on the magnesia surface, where the antiferromagnetic state is energetically more favorable compared to the ferromagnetic state. Based on the charge transfer and the density of state distribution, the interaction with the magnesia substrate does not affect the magnetic properties of the CoO monolayer. [ABSTRACT FROM AUTHOR]

Urbanization poses a challenge to bird communication due to signal masking by ambient noise and reflective surfaces that lead to signal degradation. Bird species (especially oscines) have been shown to alter their singing behaviour to increase signal efficiency in highly urbanized environments. However, few studies on the effects of noise on song structure have included birds with low frequency vocal signals which may be especially vulnerable to noise pollution due to significant frequency overlap of their signals with traffic noise. We compared the perch coos of spotted doves ( Streptopelia chinensis ), a species with very low frequency vocalizations, in different background noise levels across urban and peri-urban areas in Hong Kong. We documented a 10% upward shift in the minimum frequency of coos of spotted doves across the noise gradient (a relatively small but significant shift), and a reduced maximum frequency in urban habitats with a higher density of built up area. Hong Kong doves had significantly higher minimum and maximum frequencies than doves from throughout their range (from mostly rural sites). Our results indicate that urban species with extremely low sound frequencies such as doves can alter their vocalizations in response to variable urban acoustic environments. [ABSTRACT FROM AUTHOR]

This article validates the results of a study by Laroche, Papadopoulos, Heslop, and Bergeron (2003). In contrast to the original study that was carried out in Canada with English-speaking Canadians and French-speaking Canadians, this replication examines subcultural differences on country and product evaluations ofGerman-speaking South Tyroleans and Italian-speaking South Tyroleans,who live in the most northern Italian region. Overall, it can be confirmed that country/region and/or nationalitymay not be a suitable proxy for culture and therefore may not be suitable variables for country-of-origin studies. [ABSTRACT FROM AUTHOR]

Rechargeable Li-O 2 batteries show great potential owing to the super high energy density. However, the poor kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) limits their practical application. The exploration of noble metals-free cathode catalysts with high catalytic activity on both ORR and OER is still a big challenge. Herein, CoO has been confined into bimodal mesoporous carbon frameworks (CoO@BMC) via a wet-chemistry impregnation approach and the performance of CoO@BMC as cathode catalyst for Li-O 2 batteries has been largely improved. For comparison, CoO@CMK-3 composite has also been prepared. In comparison with bulk CoO, BMC and CoO@CMK-3, CoO@BMC based cathode shows a higher initial capacity (∼4000 mA h g −1 ), much higher cycling stability, higher rate capability and lower overpotential,which can be largely attributed to the synergetic effect of CoO and hierarchical BMC on both ORR and OER. In addition, the formation and decomposition of Li 2 O 2 and side products in the process of ORR and OER have also been analyzed and the results indicate that CoO@BMC nanocomposite can efficiently promote the decomposition of Li 2 O 2 and even some side products of carbonates. [ABSTRACT FROM AUTHOR]

We report on the strategy of Cu doping inducing the nanosize effect of CoO and their application as anode for lithium ion batteries. With an increase of Cu-doped amount, the structures and morphologies of CoO have special changes. The 0.05 mol Cu-doped CoO shows straw-like bundle structure assembled by nanorods, and the nanorods consist of ultra small nanoparticles (about 6–8 nm). Meanwhile, it shows an excellent rates performance and cycle life. The capacity of 800 mA h g −1 is obtained at 0.5 C after 80 cycles. The highest discharge capacity is 580 mA h g −1 at 10 C and the discharge capacities are relatively stable for 1000 cycles as an anode for Li-ion battery. Therefore, the controllable Cu-doped CoO composite could be deemed to be a potential candidate as an anode material. [ABSTRACT FROM AUTHOR]

Facile synthesis and electrochemical performance of a CoO nanoparticles/porous carbon composite used as an anode in Li-ion batteries is reported in this work. CoO nanoparticles (5-10 nm in size) were embedded in a disordered porous carbon network using a simple template-free chemical method. The synthesized composite work well as an anode material for Li-ion batteries by delivering stable cycle life and highly reversible capacities of 480 mAhg at 500mAg, which is higher than that of commercially available graphite electrodes and is comparable to values reported for CoO/graphene composites. [ABSTRACT FROM AUTHOR]

A new core-shell nanostructure of CoO@MnO 2 nanowire@nanosheetarrays(NNSs) was designed and directly grown on a 3D nickel foam by a simple two step solution method combined with a post annealing treatment in Ar gas. The MnO 2 nanosheets can grow directly on the CoO precuor nanowires without any pretreatment, and its thickness on the CoO nanowire arrays (NAs) can also be tailored by easily adjusting the second step hydrothermal time. When acting as a electrochemical supercapacitor, the CoO@MnO 2 NNAs delivers a highly enhanced specific capacitance of 3.03 F cm −2 (about 1515 F g −1 ) with a wide potential window of 0.8 V at 2.0 mA cm −2 , which is superior to most reported Co 3 O 4 based core-shell NNAs supercapacitive electrodes. An asymmetric supercapacitor devices based on these CoO@MnO 2 NNAs and aqueous electrolyte showed with a high-energy density of 0.37 mWh cm −2 at a power density of 1.7 mW cm −2 , a high power density of 34.4 mW cm −2 at 0.20 mWh cm −2 and a long-term cycling ability, implying its great potential application in high-performance electrochemical supercapacitor. [ABSTRACT FROM AUTHOR]

Carbon based materials as one promising cathode to accommodate the insoluble and insulating discharge products (Li2O2) for lithium oxygen (Li-O2) batteries have attracted great attention due to their large energy density store ability compared with the other carbon-free cathodes. However, the side reaction occurring at carbon/Li2O2 interfaces hinders their large-scale application in Li-O2 batteries. Herein, a simple and cost-effective strategy is developed for the growth of core-shell-like Co/CoO nanoparticles on 3D graphene-wrapped carbon foam using 3D melamine foam as the initial backbone. This unique 3D hierarchical carbonized melamine foam-graphene-Co/CoO hybrid (CMF-G-Co/CoO) with a continuous conductive network and elastic properties is used as binder-free oxygen electrode for Li-O2 batteries. Electrochemical and structural measurements show that a synergistic effect is observed between Co/CoO and graphene, where Li2O2 grows on the Co/CoO surfaces instead of the carbon surfaces at the initial discharge state (500 mAh ), indicating the reduced carbon/Li2O2 interfaces and alleviative side reactions during the electrochemical process. Importantly, the CMF-G-Co/CoO electrode can achieve greatly improved cycle life over the electrode without aid of the Co/CoO. Furthermore, it delivers a large capacity of ≈7800 mAh and outstanding rate capability, exhibiting the great potential for the application in Li-O2 batteries. [ABSTRACT FROM AUTHOR]

Current market trends of the switching power supplies industry require even lower energy losses in power conversion systems with maintenance of satisfactory initial permeability levels. Typical operation conditions refer to a frequency of 100 kHz, an induction level of 200 mT and a steady state temperature of 100° C. In this work the development of a polycrystalline Mn–Zn ferrite material that exhibits initial relative magnetic permeability above 2500 and very low power losses at 100 kHz, 200 mmT and 100° C is presented. The Mn–Zn ferrite samples were prepared by the conventional solid state reaction method. Sintering was performed under controlled atmosphere conditions. The combinatorial role of TiO 2 and CoO together with Zn content, as well as the effects of the process parameters on the magnetic performance of the Mn–Zn ferrite was evaluated. It is shown that the development of the adequate polycrystalline microstructure that is characterized by (a) high sintered density, (b) homogenous grain size that is free of morphological or chemical pinning defects and (c) high resistivity grain boundary structure, can be achieved by means of appropriate compositional and dopant adjustment, anisotropy control and specific resistivity optimization. The newly developed Mn–Zn ferrite is characterized by high sintered density of 4.91 g/cm 3 , initial magnetic permeability of 2512 (at 10 kHz, 0.1 mT, 25 °C), high saturation magnetic flux density of 560 mT (at 10 kHz, 1200 A/m, 25 °C) and very low power losses (Pv) of 224 mW/cm 3 (at 100 kHz, 200 mT, 100 °C) combined with very low power losses of 470 mW/cm 3 even at room temperature, establishing it as ideal for power applications. [ABSTRACT FROM AUTHOR]

A large amount of conducting materials has typically been blended with transition metal oxides (MO, M = Fe, Co, Ni, Cu), and their electrochemical properties as the anode in lithium-ion batteries have been studied. Here, we report that a higher content of the conducting material results in poorer cycling stability of CoO. From the analysis of the cumulative irreversible capacity loss, a high content of conducting material is proven to promote irreversible electron consumption for the growth of a polymeric surface layer which is the origin of degradation. Furthermore, its formation is mathematically modeled on the basis of the Butler-Volmer relation. From the physical parameters of the polymeric surface layer determined by fitting the model to the experimental data, the degradation mechanism of CoO is discussed. [ABSTRACT FROM AUTHOR]

Low reflective CoO coatings are processed by chemical vapor deposition from Co 2 (CO) 8 at temperatures between 120 °C and 190 °C without additional oxygen source. The optical reflectivity in the visible and near infrared regions stems from 2 to 35% depending on deposition temperature. The combination of specific microstructural features of the coatings, namely a fractal “cauliflower” morphology and a grain size distribution more or less covering the near UV and IR wavelength ranges enhance light scattering and gives rise to a low reflectivity. In addition, the columnar morphology results in a density gradient in the vertical direction that we interpret as a refractive index gradient lowering reflectivity further down. The coating formed at 180 °C shows the lowest average reflectivity (2.9%), and presents an interesting deep black diffuse aspect. [ABSTRACT FROM AUTHOR]

We report the room temperature ferromagnetic properties of graphene adsorbed by cobalt oxide using electrochemical method. The cobalt oxide doping onto graphene was carried out in 0.1 M LiCoO 2 /DI-water solution. The doped graphene thin film was determined to be a single layer from Raman analysis. The CoO doped graphene has a clear ferromagnetic hysteresis at room temperature and showed a remnant magnetization, 128.2 emu/cm 3 . The temperature dependent conductivity of the adsorbed graphene showed the semiconducting behavior and a band gap opening of 0.12 eV. [ABSTRACT FROM AUTHOR]

The electronic structure and magnetism of La-doped CoO systems have been studied by first-principles calculations based on density functional theory. The La dopant concentrations are set to 3.125% and 2.083%, respectively. It is found that La substitution makes the system presents a half-metallic characteristic. Interestingly, La impurity induces the density of states at Fermi level from its surrounding Co and O atoms, while La itself didn’t contribute to density of states. By changing the concentration of La dopant, the band gap and charge density of systems are changed. The total magnetic moments of all the La-doped systems are about 2.118 μB, which is not dependent on the impurity concentration. The tendency of structures, band gap, density of states and magnetic moments are the same by LDA and PBE methods. [ABSTRACT FROM AUTHOR]

Background: Although the surface area metric has been proposed as a possible dose-metric for nanoparticles (NPs), it is limited to low-solubility NPs and the dose-metric for high-solubility NPs is poorly understood. In this study, we aimed to assess the appropriate dose-metric or response-metric for NPs using two cobalt (Co)-based NPs, cobalt monoxide (CoO) and cobalt oxide (Co3O4), which both show distinctive solubility, and determine the role of their soluble Co ions in inflammation. Methods: We evaluated the physicochemical properties of NPs, including solubility in artificial lysosomal fluid (ALF, pH 5.5). Acute lung inflammogenicity was evaluated by bronchoalveolar lavage fluid analysis using the rat intratracheal instillation model. The appropriate response-metric was then determined by plotting several dose-metrics against parameters for lung inflammation. To investigate the effect of the soluble fraction of CoO NPs, the equivalent doses of Co ions from CoCl2 were instilled. Results: The Co3O4 and CoO NPs showed about 11.46 % and 92.65 % solubility in ALF, respectively. Instillation of Co3O4 NPs produced neutrophilic inflammation, but CoO NPs induced eosinophilic inflammation. The number of eosinophils showed good correlation with the soluble Co ions dose from NPs (r2 = 0.987, p <0.001), while the number of neutrophils showed good correlation with the surface area dose of the biopersistent NPs (r2 = 0.876, p <0.001). Instillation of CoCl2 showed a similar type and magnitude of inflammation as CoO NPs. Conclusions: In the Co-based NPs, the eosinophilic inflammation was produced by Co ions based on the ion metric, while the neutrophilic inflammation was developed based on the surface area metric of the biopersistent NPs. [ABSTRACT FROM AUTHOR]

A novel stereoscopic snowflake-like CoO material is synthesized via a simple two-step process, including the hydrothermal process for the formation of the stereoscopic snowflake-like Co(OH)F as precursor and thermal conversion process to CoO without altering the original shape of the precursor. The possible formation mechanism of the stereoscopic snowflake-like morphology of CoO was investigated by scanning electron microscopy and X-ray diffraction patterns. The hydrothermal temperature and NHF were critical to the formation of stereoscopic snowflake-like morphology of CoO. The supercapacitor properties of as-prepared CoO were investigated by the electrochemical measurements on a conventional three-electrode system. [ABSTRACT FROM AUTHOR]

CoO-decorated ZnS nanorods were synthesized by the thermal evaporation of ZnS powders followed by a sol-gel process for CoO-decoration. The acetone gas sensing properties of multiple-networked pristine and CoO-decorated ZnS nanorod sensors were examined. The diameters of the CoO nanoparticles ranged from 4 to 20 nm. The multiple networked pristine ZnS nanorods and CoO-decorated ZnS nanorod sensors showed responses of 156-364% and 198-1,650% to 10-500 ppm of acetone at room temperature under UV illumination at 2.2 mW/cm, respectively. The response and recovery times of the ZnS nanorod sensor at 500 ppm of acetone was reduced from 52 s to 26 s and from 192 s to 110 s, respectively, by CoO-decoration. The responses of the sensors exhibited strong dependence on the UV illumination intensity. The responses of the pristine ZnS nanorod and CoO-decorated ZnS nanorod sensors to 500 ppm of acetone at room temperature increased from 112 to 364% and from 132 to 1650%, respectively. This paper discusses the underlying mechanisms of the enhanced response of the ZnS nanorod sensor to acetone gas by CoO-decoration and UV irradiation. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A series of porous carbon/CoO (NZMC-18(6)-700-3/CoO) composite materials with different cobalt contents were synthesized at low reaction temperature using a facile chemical precipitation method. The morphology and crystal structure of the materials were evaluated on field emission scanning electron microscope and X-ray diffraction, respectively. The results show that composite materials possess incompact lamellar structure with some irregular agglomerated CoO particles adhering. The calcination temperature has a distinct influence on the morphology and electrochemical properties of porous carbon/CoO composites. The electrochemical performances were measured by constant current charge/discharge tests, cyclic voltammetry, and electrochemical impedance spectroscopy tests. It is illustrated that the composite materials have outstanding charge storage ability and the specific capacitance can reach up to 462 F g when the calcination temperature and cobalt content are 250 °C and 95 wt.%. With the increase of scan rate, the response current increases, and the anodic peaks and cathodic peaks shifted to higher potential and lower potential, respectively, which both illustrate that the material has excellent reversibility. The combination impedance of the electrode is only 0.674 Ω cm at a calcination temperature of 250 °C and is much less than those at other calcination temperatures which means that the electrode material has good conductivity. [ABSTRACT FROM AUTHOR]

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Nanostructures of Co/CoO/Co 3 O 4 were synthesized by a chemical method at different temperatures between 300 and 600 °C. The samples were characterized by TG, XRD, TEM and SQUID magnetometry. The lower temperature sample (300 °C) is composed of Co, CoO and Co 3 O 4 , while the higher temperature sample only contains Co 3 O 4 . All the samples exhibit exchange bias effect. The exchange bias is observed below 205 K (below the CoO blocking temperature) for the sample prepared at lower temperature (300 °C), while for other samples (350–600 °C), the effect is observed below 35 K (below the Néel temperature of Co 3 O 4 , T N =40 K). The roles of CoO and Co 3 O 4 on the magnetic properties and the mechanisms governing exchange bias effect have been discussed. [ABSTRACT FROM AUTHOR]

A nanocomposite of CoO and reduced graphene oxide (CoO-rGO) was successfully synthesized as an anode material for lithium-ion batteries by a one-pot microwave-assisted hydrothermal process. In the nanocomposite, CoO nanoparticles with narrow size distribution in the range of 10-30 nm uniformly decorated the surface of rGO, indicating that rGO could act as a two-dimensional template for the heterogeneous precipitation of CoO nanoparticles. To investigate the effect of mass ratios of CoO and rGO on the electrochemical properties, the CoO loading in the nanocomposite was controlled during the microwave-assisted hydrothermal synthesis. The resulting nanocomposite electrode exhibited high electrochemical performance in terms of specific capacity and cyclability, indicating that rGO served as an efficient template material to provide a highly conducting and buffering network for CoO nanoparticles. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The country of origin (CoO) information has a certain influence on the consumer's evaluation of the product and also on his purchasing decision (Roth & Diamantopoulos 2009; Chu, et al., 2010; Pouta et al., 2010). This is happening particularly because consumers are concerned more and more of various quality issues on how food is produced and where it comes from (Pouta et al., 2010; Teuber 2011), since due to globalization opportunities, companies are able to distribute their goods all around the world (Aiello et al., 2009). Moreover, research on the CoO effects has become a chief area of interest in the field of international marketing (Chu, et al., 2010; Bloemer, Brijs & Kasper 2009; Diamantopoulos & Zeugner-Roth 2010), even though it is a controversial field (Bloemer, Brijs & Kasper 2009; Diamantopoulos & Zeugner-Roth 2010), since it is not clear yet to which degree the CoO effect influences the consumer evaluations (Bloemer, Brijs & Kasper 2009). However, marketers use the CoO labeling or the terroir concept in their marketing strategies as [ABSTRACT FROM AUTHOR]

Recent legislation by the United States and European Union governments now mandates the provision of country-of-origin (COO) information at the point of purchase for a variety of meats, fruits, vegetables, and other assorted food products. To better understand the significance of these regulatory changes, two decades of existing COO food labeling research are synthesized, reviewed, and discussed. The implications for two primary sets of actors within aggregate marketing systems, consumers and practitioners, are then discussed from a macromarketing perspective. Based on the reviewed literature, the authors conclude that little generalizable knowledge about COO food labeling effects exists, and further identify a lack of sufficient theoretical application and development as a primary reason. Consequently, the exact impact of mandatory (and voluntary) COO labeling initiatives for consumers and practitioners still remains unclear and highly debatable. Thus, as these initiatives continue to make country-of-origin labeling more commonplace around the world, it is crucial that additional theory-driven research be conducted, especially from a macromarketing perspective, to foster more generalizable knowledge about the complex role of COO information in aggregate food marketing systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lithium and cobalt were recovered efficiently from spent lithium-ion batteries. • Low temperature carboreduction was used to produce high-purity Li 2 CO 3 and CoO. • The carboreduction mechanism of the spent cathode material was investigated. • The research findings bear relevance to circular economy. The recycling of value metals from spent lithium-ion batteries (LIBs) have interesting benefits such as reduction of natural resources exploitation and minimization of energy consumption from mining operations. The aim of this work was to recover lithium, cobalt and manganese from the cathode material present in spent LIBs through a pyrometallurgical process of carboreduction. The method consisted in mixing the cathode material with carbon black and a subsequent heat treatment of the mixture under nitrogen atmosphere. The products obtained were separated by water leaching. To elucidate the reactions and the mechanism involved in the carboreduction process, different studies involving thermodynamic calculations, thermal gravimetric analysis (TGA), differential thermal analysis and X-ray diffraction (XRD) were carried out. The results indicated that Li 2 CO 3 , CoO and MnO are produced at temperatures lower than 600 °C. The results of atomic absorption spectrometry (AAS) showed that the extraction percentage of lithium was greater than 90% at temperatures between 550 and 600 °C. The products obtained through the process presented here could be used in either the manufacture of new batteries or other industrial applications. [ABSTRACT FROM AUTHOR]

We present the comparative study of the structural and magnetic properties of the NiFe/CoO and CoO/NiFe bilayers grown on both MgO(111) and MgO(100) substrates by using the ion beam sputtering technique. We observed that crystallographic orientation and crystal quality strongly affected the exchange bias properties of the bilayers. The NiFe layers showed fourfold magnetocrystalline anisotropy when we used MgO(100) substrate and uniaxial anisotropy when we used MgO(111) substrate. When the CoO layer is grown on MgO(111) and MgO(100) substrates as a first layer, instead of the NiFe, the increase of the crystalline quality and stoichiometric CoO phase has been achieved so that the exchange bias field increases by five and three times for NiFe/CoO/MgO(111) and NiFe/CoO/MgO(100) systems, respectively. The blocking temperature significantly increases for NiFe/CoO on MgO(111) and (100) substrates, indicating the increase of the stoichiometric stable Co1O1 phase in the exchange-biased system. The magnitude of the exchange bias field is 800 Oe at 10 K for NiFe/CoO/MgO(111) and more than two times as compared to that of NiFe/CoO/MgO(100). This high exchange bias value observed for NiFe/CoO/MgO(111) was explained with the uncompensated spins in CoO(111) surface. We also carried out training effect measurements to observe the durability of the exchange bias for technological applications. [ABSTRACT FROM AUTHOR]

Three-dimensional CoO-graphene frameworks (3D-CGFs) are prepared with a one-pot hydrothermal method. CoO particles are in situ anchored on graphene sheets, and the resulting composite self-assembles into 3D architecture during the hydrothermal treatment. Scanning electron microscope, transmission electron microscope, powder X-ray powder diffraction, and Raman spectroscopy are employed to characterize the sample. When tested as anode materials for lithium-ion batteries, 3D-CGFs demonstrate remarkable electrochemical lithium storage properties, such as large and stable reversible capacity (>530 mAh g at 500 mA g over 300 cycles), good capacity retention (88 % retention after 300 cycles at 500 mA g compared with the 4th cycle), excellent high-rate performance (515 mAh g at 1 A g), making it a promising candidate for high-performance anode materials, especially for high-rate lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Highlights: [•] CoO system with one Co vacancy shows a half-metallic characteristic. [•] CoO systems with two Co vacancies on 9, 11 and 9, 16 positions show the half-metallic character. [•] CoO with two Co vacancies on 1, 9 positions is metallic. [•] CoO with two Co vacancies on other positions is ferromagnetic insulators. [ABSTRACT FROM AUTHOR]

Electronic structure and magnetism in CoO systems doped with Zn and Ti have been studied by the first-principles calculations. The ground state is an antiferromagnetic insulator in CoO. The Zn-doped CoO becomes ferromagnetic insulators, but the Co 2+ magnetic moment is enhanced due to the Zn incorporation. By introducing one Ti atom into CoO, the conductivity is enhanced by comparing with pure CoO. The system of CoO doped with two Ti atoms on 9 and 11 substitution positions shows a half-metallic character due to the strong hybridization between Ti and Co atoms. Ti 2 Co 14 O 16 systems with Ti atoms at 9, 10 and 9, 16 and 1, 9 positions show the metallic characteristics with a large spin polarization, which can enhance the conductivity of CoO systems. [ABSTRACT FROM AUTHOR]

The CoO nanocubes were prepared by using hydrogen peroxide (HO) as oxidant, Co(NO)·6HO as a cobalt source. The products were characterized in detail by multiform techniques: scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The prepared CoO nanocubes were applied to study the electrocatalytic reduction of hydrogen peroxide (HO) in 0.01 M pH 7.0 phosphate buffer medium. The CoO nanocubes exhibit remarkable electrocatalytic activity for HO reduction. Furthermore, the obtained CoO nanocubes have been employed as electrode materials for electrochemical sensing HO. [ABSTRACT FROM AUTHOR]

We present, for the first time, on a facile route for the fabrication of highly crystalline CoO nanoparticles using trietanolamine (TEA) assisted hydrothermal synthesis route and single precursor. Synthesized material has been evaluated for its structural, morphological and magnetic properties using x-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM) techniques. The material has been identified as highly crystalline CoO, with superparamagnetic character due to size confinement. Estimated particle size from SEM is about 10 nm, which is close to the magnetic domain size (estimated from VSM as 8.4 ± 1.7 nm) and the crystallite size (estimated from XRD as 11 pm 4 nm), which reveal nearly single crystalline character of CoO nanoparticles. The suggested route is facile, which provides a good size control over the nanoparticles, and can be used for the fabrication of other ceramic materials. [ABSTRACT FROM AUTHOR]

The varistor characteristics of 0.1-3.0 at. % Co-doped ZnO have been investigated. Three kinds of deep bulk trap levels of 0.16, 0.25, and ~0.31 eV were identified as donor levels by admittance spectroscopy. Oxygen vacancy ( V) appeared preferentially in 0.5-3.0 at. % Co-doped ZnO. From J-E characteristics nonohmic behavior was seen in this binary system while the nonlinear coefficient α changed between 3 and 35 depending on the composition. For 1.0 at. % Co-doped ZnO, two distinguishable activation energies of 0.65 eV and 1.04 eV related with grain boundary phenomena were confirmed above and below ~520 K by impedance and modulus spectroscopy. It is believed that the varistor behavior of Co-doped ZnO stems from the formation of double Schottky barrier by the valence change of Co ions in ZnO grains as well as oxygen chemisorption at the grain boundaries on heating and subsequent cooling. [ABSTRACT FROM AUTHOR]

SnO@CoO hollow nano-spheres have been prepared using the template-based sol-gel coating technique and their electrochemical performance as an anode for lithium-ion battery (LIB) was investigated. The size of synthesized hollow spheres was about 50 nm with the shell thickness of 7-8 nm. The fabricated SnO@CoO hollow nano-sphere electrode exhibited an extraordinary reversible capacity (962 mAh·g after 100 cycles at 100 mA·g), good cyclability, and high rate capability, which was attributed to the Co-enhanced reversibility of the LiO reduction reaction during cycling. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

First-principles calculations with GGA+U approach are carried out in studying the properties of intrinsic defects of the wurtzite MnO, and CoO. For intrinsic MnO, it shows tunable p-type and n-type conductivity under O rich and O poor conditions, respectively. For intrinsic CoO, it is easy to be designed as p-type semiconductors under O rich condition, but hard for n-type. We expect that the tunable p/n conductivity of MnO could open a new application prospect for the wurtzite semiconductor materials. [ABSTRACT FROM AUTHOR]

Over the past few years, electrocatalysis for the oxygen reduction reaction in alkaline solutions has undergone tremendous advances, and non-precious metal catalysts are of prime interest. In this study, we present a highly promising CoO@Co/N-C (where N-C represents a N-doped carbon material) catalyst, achieving an onset potential of 0.99 V (versus the reversible hydrogen electrode (RHE)) and a limiting current density of 7.07 mA·cm (at 0.3 V versus RHE) at a rotation rate of 2,500 rpm in an O-saturated 0.1 M KOH solution, comparable to a commercial Pt/C catalyst. The H-O alkaline fuel cell test of CoO@Co/N-C as the cathode reveals a maximum power density of 237 mW·cm. Detailed investigation clarifies that a synergistic effect, induced by C-N, Co-N-C, and CoO/Co moieties, is responsible for the bulk of the gain in catalytic activity. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]