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A novel well-defined precatalyst for ammonia-selective catalytic reduction of NOx (NH3-SCR), namely, [W(≡CtBu)(CH2tBu)3]/CeO2, was prepared by surface organometallic chemistry and then characterized. Due to the high dispersion of the active phase, this catalyst showed excellent activity after calcination at 500 °C, described by up to 99% conversion of NOx, high N2 selectivity, broad operation temperature window (225–500 °C), and extremely high durability for the selective catalytic reduction of NOx with NH3. [ABSTRACT FROM AUTHOR]

The linear, two-coordinate and isostructural heteroleptic [M(IPr){N(SiMe3)2}] (IPr = 1,3-bis(diisopropylphenyl)-imidazol-2-ylidene), formally MI complexes (M = Co, 3; Fe, 4) were obtained by the reduction of [M(IPr)Cl{N(SiMe3)2}] with KC8, or [Co(IPr){N(SiMe3)2}2] with mes*PH2, mes* = 2,4,6-tBu3C6H2. The magnetism of 3 and 4 implies CoII and FeII centres coupled to one ligand-delocalized electron, in line with XPS and XANES data; the ac susceptibility of 4 detected a pronounced frequency dependence due to slow magnetization relaxation. Reduction of [Fe(IPr)Cl{N(SiMe3)2}] with excess KC8 in toluene gave the heteronuclear ‘inverse-sandwich’ Fe–K complex 7, featuring η6-toluene sandwiched between one Fe0 and one K+ centre. [ABSTRACT FROM AUTHOR]

Carbon serves as one of the best coating materials for the cathode in lithium ion batteries. This is because it can solve two main problems, which are surface deterioration and poor electrical conductivity. However, the conventional carbon coating procedures and, chemical carbonization processes, are especially difficult to implement for the oxide cathode, which could thereby deteriorate the oxide structure. We prepared a new dry 100 nm-thick homogeneous multi-walled carbon nanotube (MWCNT) coating on the high-capacity oxide cathode material, Li1.17Ni0.17Co0.1Mn0.56O2, by applying shear stress without breaking down the crystal structure or morphology of the cathode. The electronic conductivity of the carbon composite with the coated sample is 170 mS cm−1, which is over 40 times as much as the conductivity of the pristine cathode containing the same amount of carbon. In addition, at a high current condition of 2450 mA g−1, a specific capacity of 103 mA h g−1 is observed even with 3 percent of the carbon (in weight) constituting the coated MWCNT. The unconventionally improved performances are explained by the suppression of the electronic resistance and surface charge transfer resistance by electrochemical analyses. [ABSTRACT FROM AUTHOR]

5-Hydroxy-1H-indazole (HI) is investigated as an effective film-forming additive for an over-lithiated layered oxide (OLO) positive electrode. The protective film that is generated by oxidative decomposition of the additive (HI) prior to the carbonate electrolyte is thin and less resistive. As a result, a full cell comprised of OLO/graphite in the HI-added electrolyte gives a better cycling performance. [ABSTRACT FROM AUTHOR]

Does the Li4Ti5O12 electrode need a carbon additive in lithium-ion batteries? We answered this question in our previous work by showing that the partially reduced Ti4+ on the surface of Li4Ti5O12 could provide enough electronic conductivity to initiate the electrochemical process. In this work, we discuss the generally accepted fact that a solid electrolyte interphase (SEI) is hardly formed on the surface of the Li4Ti5O12 electrode owing to its high redox potential by using the carbon-free Li4Ti5O12 electrode to exclude the influences of carbon. In contrast to the previous argument, Li4Ti5O12 was found to have certain reactivity towards electrolytes at room and high temperature (60 °C). Moreover, in the presence of carbon in the electrode (i.e. the conventional electrode formulation), the reactivity of the electrode towards an electrolyte was significantly increased at high temperatures. These results were discussed based on surface analyses and electrode morphology observation before and after cycling, and correlated with the electrochemical performance. [ABSTRACT FROM AUTHOR]

Nitrogen in a thin HfO2−xNx layer was observed in the form of dinitrogen molecules by atom probe microscope measurements. To evaluate the chemical state, an ab initio calculation based on monoclinic HfO2 was performed with using oxygen vacancy models combined with interstitial or substitutional nitrogen. The formation of a hafnium dinitrogen complex near the oxygen vacancy was found to considerably lower the system energy. This result contrasts the substitutional nitrogen complex passivating the oxygen vacancy level in the cubic structure and suggests that the structural stability enhanced by the oxygen vacancy-dinitrogen complex restrains the formation of grain boundaries in amorphous HfO2, which are responsible for the large leakage current. [ABSTRACT FROM AUTHOR]

A VOx-impregnated oxide cathode for lithium ion batteries exhibits a substantial drop in oxygen evolution during high voltage operation. An electrolyte was found to catalyze the gas evolution, and the VOxlayer could protect the cathode oxide surface from the electrolyte and stabilize the surface oxide ions during their electrochemical oxidation. [ABSTRACT FROM AUTHOR]

A novel well-defined precatalyst for ammonia-selective catalytic reduction of NOx (NH3-SCR), namely, [W(≡CtBu)(CH2tBu)3]/CeO2, was prepared by surface organometallic chemistry and then characterized. Due to the high dispersion of the active phase, this catalyst showed excellent activity after calcination at 500 °C, described by up to 99% conversion of NOx, high N2 selectivity, broad operation temperature window (225–500 °C), and extremely high durability for the selective catalytic reduction of NOx with NH3. [ABSTRACT FROM AUTHOR]

High content nitrogen, sulfur and phosphorus heteroatoms assembled in tree-like dendrimers (DG n ) are confined within the galleries of two-dimensional graphene oxide (GO). The presence of the ternary diethyl- N -ethyl-ammonium groups on the dendrimer peripheries ensures the exfoliation of graphene sheets thereby affording interfacially bridged, three-dimensional heteroatom-enriched graphene-based hybrid nanostructures (DG n -GO). Dendrimer generation (from 1 to 4) that reflects the bulkiness of these conceived nano-trees impacts increasingly the degree of dispersion-exfoliation and sheet desordering. The long-term stability of these aqueous suspensions associated with their handling flexibility allows uniform accommodation of the resulting hybrid materials as flame-retardants in bioplastics., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The linear, two-coordinate and isostructural heteroleptic [M(IPr){N(SiMe 3 ) 2 }] (IPr = 1,3-bis(diisopropylphenyl)-imidazol-2-ylidene), formally M I complexes (M = Co, 3; Fe, 4) were obtained by the reduction of [M(IPr)Cl{N(SiMe 3 ) 2 }] with KC 8 , or [Co(IPr){N(SiMe 3 ) 2 } 2 ] with mes*PH 2 , mes* = 2,4,6-tBu 3 C 6 H 2 . The magnetism of 3 and 4 implies Co II and Fe II centres coupled to one ligand-delocalized electron, in line with XPS and XANES data; the ac susceptibility of 4 detected a pronounced frequency dependence due to slow magnetization relaxation. Reduction of [Fe(IPr)Cl{N(SiMe 3 ) 2 }] with excess KC 8 in toluene gave the heteronuclear 'inverse-sandwich' Fe-K complex 7, featuring η 6 -toluene sandwiched between one Fe 0 and one K + centre.

A carbon-free Li(4)Ti(5)O(12) electrode has shown excellent electrochemical performance without any effort to enhance the electrical conductivity. Partial reduction of Ti(4+) and a metallic Li(7)Ti(5)O(12) phase are suggested to be possible origins of the exceptional behavior., (This journal is © The Royal Society of Chemistry 2012)

When the electrode is specifically designed by impregnation with an electronic and ionic mixed-conductor, improvement in the electrochemical properties was observed. The presence of an active redox center may contribute to the enhancement of the surface electronic/ionic transport properties by enhancing electrical connection and isotropic Li(+) ion transport.