- Transition-Metal Carbodiimides as Molecular Negative Electrode Materials for Lithium- and Sodium-Ion Batteries with Excellent Cycling Properties
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We report evidence for the electrochemical activity of transition-metal carbodiimides versus lithium and sodium. In particular, iron carbodiimide, FeNCN, can be efficiently used as negative electrode material for alkali-metal-ion batteries, similar to its oxide analogue FeO. Based on 57Fe M?ssbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe-NCN into Li/Na-NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well-established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron carbodiimide does not require heavy treatments (such as nanoscale tailoring, sophisticated textures, or coating) to obtain long cycle life with current density as high as 9A g-1 for hundreds of charge-discharge cycles. Similar to the iron compound, several other transition-metal carbodiimides Mx(NCN)y with M=Mn, Cr, Zn can cycle successfully versus lithium and sodium. Their electrochemical activity and performance open the way to the design of a novel family of anode materials.
- Sougrati, Moulay T.,Darwiche, Ali,Liu, Xiaohiu,Mahmoud, Abdelfattah,Hermann, Raphael P.,Jouen, Samuel,Monconduit, Laure,Dronskowski, Richard,Stievano, Lorenzo
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- Temperature-dependent synthetic routes to and thermochemical ranking of α-and β-SrNCN
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White powdery β-SrNCN was obtained by the solid-state metathesis between Srl2 and ZnNCN at 843 K, by the reaction of Srl2, CsCN, and CsN3 in tantalum cylinders at the same temperature, and from the direct reaction between
- Krings, Michael,Wessel, Michael,Wilsmann, Wolfgang,Mueller, Paul,Dronskowski, Richard
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- Zinc cyanamide, Zn(CN2)
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Single crystals of the title compound have been grown by annealing microcrystalline zinc cyanamide at 843 K in silver crucibles. Zn(CN2) crystallizes as colourless prisms. The crystal structure is composed of corner-linked ZnN4/2 tetrahedra. Carbon and nitrogen form (CN2)2- dumb-bells with the C atom on a twofold axis. Nitrogen is approximately trigonally planar, coordinated by two Zn atoms and one C atom.
- Becker, Michael,Jansen, Martin
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- Nonaqueous synthesis of metal cyanamide semiconductor nanocrystals for photocatalytic water oxidation
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Herein, we report nonaqueous synthesis of metal cyanamide semiconductor nanocrystals, including Ag2NCN nanorods (NRs), ZnNCN NRs and PbNCN nanoparticles. The as-prepared Ag2NCN NRs with a band gap of 2.35 eV are applied as photocatalysts for water oxidation. Their oxygen evolution rate (280.7 μmol h-1 g-1) is much higher than that of Ag2NCN microcrystals (24.0 μmol h-1 g-1).
- Zhao, Wei,Pan, Jie,Huang, Fuqiang
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- Preparation method and application of zinc carbodiimide material
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The invention provides a preparation method of a zinc carbodiimide material. The method comprises the following steps: 1) uniformly mixing octan zinecnaty and oxalic acid, grinding, and drying to obtain a zinc oxalate precursor; 2) uniformly mixing the zinc oxalate precursor and melamine, grinding, calcining and cooling, and grinding again, thereby obtaining the needed zinc carbodiimide material.The invention further provides application of the zinc carbodiimide material serving as a photocatalyst in degradation of environmental pollutants and a method for degrading the environmental pollutants. According to the preparation method and application of the zinc carbodiimide material provided by the invention, the reactive raw materials are simple and readily available, the reaction conditions are mild and easy to control, the preparation yield is high, the preparation steps are simple and feasible, the production cost is low, and environmental pollution is avoided. The prepared zinc carbodiimide material is stable in structure, has high photocatalytic activity, is capable of effectively degrading or discoloring the environmental pollutants and has excellent popularization and application value.
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Paragraph 0040; 0042; 0048; 0053; 0058
(2018/11/22)
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- Copper-zinc oxide catalysts. Part IV. Thermal treatment in air, argon and hydrogen and XRD study of new bimetallic precursors - Direct formation of alloys
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Four new Cu-Zn bimetallic precursors of model catalysts for methanolization of syngas, Zn(NH3)2Cu(CN)3 (ZCA), [Zn(en)3]6[Cu5(CN)17]·nH 2O (n = 8.4) (ZCE3), [Zn(en)] [Cu(CN)3] (ZCE1) and [Zn1-xCux(en)] [Cu(CN)3] (ZCCE1), were thermally treated in air, hydrogen and argon atmosphere between 200 and 900°C. The calcinations in air yield firstly a mixture of cyano-ligand-containing compounds which transform at temperatures above 300°C to CuO and ZnO; the crystallite size of both oxides increases with temperature. The reduction in hydrogen at 300°C gives zinc cyanide and metallic copper which are converted at 450°C mainly to β′-brass including some α-and γ-alloys. The thermal treatment in argon displays the very high thermal stability of zinc cyanide to 900°C and formation of copper or α-CuZn alloy. Only the hydrogen treatment avoids the segregation of both metallic elements. The results are discussed on the basis of thermodynamic data.
- Kappenstein, Charles,?ernák, Juraj,Brahmi, Rachid,Duprez, Daniel,Chomi?, Jozef
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