Catalysts zinc blende

Ziegler-Natta catalyst A stereospecific catalyst for polymerization reactions, consisting of titanium tetrachloride and triethylaluminum. zinc-blende structure A crystal structure in which the cations occupy half the tetrahedral holes in a nearly close packed cubic lattice of anions also known as sphalerite structure. 

The cubic zinc blende form of boron nitride is usually prepared from the hexagonal or rhombohedral form at high (4—6 GPa (40—60 kbar)) pressures and temperatures (1400—1700°C). The reaction is accelerated by lithium or alkaline-earth nitrides or amides, which are the best catalysts, and form intermediate liquid compounds with BN, which are molten under synthesis conditions (11,16). Many other substances can aid the transformation. At higher pressures (6—13 GPa) the cubic or wurtzitic forms are obtained without catalysts (17). 

Gallium arsenide nanowires with a zinc-blende structure were fabricated by laser ablation of GaAs powders mixed with GazOs (no metal catalyst used). SEM obser-... 

Zeise s salt, 240 zeolite, UA, 266, 270 Ziegler-Natta catalyst, 269 zinc blende structure, 104 Zintl compound, 112, 160, 202... 

Martin-Gil et al. reported on the synthesis of cubic carbon nitride with the zinc blende structure by pyrolysis of N,N-diethyl-l,4-phenylene-diammonium sulphate at 800°C in an N2 atmosphere using Se02 as a catalyst [90]. The material obtained contained both an amorphous matrix and polycrystalline regions with crystallites of 5-50 nm in size. The sample as whole had a composition with 0.2 estimated using EELS (electron energy loss spectroscopy) data to be C N, with x and y between 3 and 4. The... 

Li et al. also reported the colloidal synthesis of Co-doped CdSe nanowires by the SLS strategy using the same reactants, except (MnSt)2 was replaced by cobalt stearate (CoSt)2 and the injection temperature was increased to 280°C. As-grown Co Cdi. Se (x = 0.3%) NWs were of 17.7 1.9nm in diameter and 1.8 0.2 pm in length with Bi catalysts located on both NW ends which demonstrated the SLS growth mechanism. The admixture of zinc blende and wurtzite structures were observed from TEM images. The diameter of the NWs can be tailored between 8 to 30 nm and the Co concentration can be tuned from 0 to 2.1% by varying the concentration of the reactants and reaction temperature. The temperature-dependent emission spectra of the Co-doped CdSe NWs were blue-shifted with increase of... 

For materials with a zinc blende cubic lattice, the solution - liquid - solid (SLS) mechanism [132] has been widely used to synthesize wirelike crystallites. The SLS method is analogous to the vapor-liquid-solid (VLS) method [133], which generates single-crystal wires in relatively large quantities. Very recently, quantum rods and wires of InAs [134] and InP [135] with controllable diameters and excellent crystallinity were synthesized by the SLS method. However, the fabrication of III-V semiconductor quantum rods (QRs) remains difficult regarding the control of size, length, and size uniformity. Another difficulty with QRs synthesized by the SLS method is residual metallic catalyst spherules (Au, In) present at the rod tip. The presence of these metal catalyst particles interferes with measurements of the optical and electronic properties of the QRs. 

Grillo Company Grillo Company recovered sulfur dioxide from zinc blende smelters. Pre-1898 tightly packed tubes, using up to 15 layers of 8-10% platinum on asbestos converted 25% sulfur dioxide and 75% air. From 1898 used calcined magnesium sulfate sprayed with platinic chloride to give 0.1-0.3% platinum on finished catalyst. Feed gas contained less sulfur dioxide. ... 

These are the polycondensation products of dlcarboxylic acids and diols. Dacron or terylene Is the best known example of polyesters. It is manufactured by heating a mixture of ethylene glycol and terephthallc acid at 420 to 460 K In the presence of zinc acetate-antimony trioxlde catalyst as per the reaction given earlier. Dacron fibre (terylene) is crease resistant and is used In blending with cotton and wool fibres and also as glass reinforcing materials in safety helmets, etc. 

The solution (pad bath) contains one or more of the amino resins described above, a catalyst, and other additives such as a softener, a stiffening agent, or a water repeUant. The catalyst may be an ammonium or metal salt, eg, magnesium chloride or zinc nitrate. Synthetic fabrics, such as nylon or polyester, are treated with amino resins to obtain a stiff finish. Cotton (qv) or rayon fabrics or blends with synthetic fibers are treated with amino resins to obtain shrinkage control and a durable-press finish. 

Mitsubishi Gas Chemical Company Inc. market BT Resin, a blend of a bismaleimide (BMI) and a triazine resin, cured by heating alone or with a zinc octoate, zinc octoate/ triethylene diamine, or zinc octoate/A,A-dimethylbenzylamine catalyst system. 

Figure 13.3 shows a magnified cross-sectional view of the cathode region of the zinc/air battery. The cathode structure includes the separators, catalyst layer, metallic mesh, hydro-phobic membrane, diffusion membrane, and air-distribution layer. The catalyst layer contains carbon blended with oxides of manganese to form a conducting medium. It is made hydro-phobic by the addition of finely dispersed Teflon particles. The metallic mesh provides structural support and acts as the current collector. The hydrophobic membrane maintains the gas-permeable waterproof boundary between the air and the cell s electrolyte. The diffusion membrane regulates gas diffusion rates (not used when an air hole controls gas diffusion). Finally the air distribution layer distributes oxygen evenly over the cathode surface. 

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