979 resultados para Cu-ZnO-ZrO2 : HZSM-5
Resumo:
中国科学院山西煤炭化学研究所
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With XRD, R-T, and ac chi measurements a comparative study on the doping effects of 3d elements in Bi(1.5)Pb(0.2)Sr(2)Ca(2)Cu(2.8)M(0.2)O(y) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, or Zn) has been carried out. The effects of the former five members are significantly different, both on phase formed and on T-c, from the latter four. It seems that the effect on phase stabilization correlates with the valency of the doped cation. In connection with the instability of the 2223 phase, the correlation has been discussed.
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ESR method has been used to study superhyperfine. interaction of I-127 in [Cu (IO5OH)(2)](5-) ion for Na4KCu(IO5OH)(2) . 12H(2)O single crystal. The main purpose of this paper is to confirm the existence of unpaired electron spin on iodine atom and to find a reasonable explanation for the spin delocalization of CU2+ ions. Based on the ESR parameters of paramagnetic [Cu(IO5OH)(2)](5-) ions, the calculated results show that about 0.77% of the unpaired eletron spin is located on each iodine atom.
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用ESR方法研究了[Cu(IO5OH)2]5-离子配合物中127I核的超超精细相互作用,旨在证实在碘离子上存在未成对电子自旋和找到一种解释Cu2+离子中电子离域的机制。根据ESR参数的计算指出碘离子上自旋密度为0.77%。
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A highly active and selective K-Pd/MnOx-ZrO2-ZnO catalyst for the one-step synthesis of 2-pentanone from ethanol is described. The possible reaction pathways for ethanol reaction over K-Pd/MnOx-ZrO2-ZnO catalyst were investigated by means of TPSR, CO2- and NH3-TPD techniques. The reactions were performed in a fixed bed continuous flow reactor. Complete conversion with high selectivity for 2-pentanone, was observed under 370 similar to 390degreesC, 2 similar to 4 MPa, GHSV = 8000 similar to 10,000 h(-1) and LHSV < 1.25 h(-1) conditions. Ethanol reactions over K-Pd/MnOx-ZrO2-ZnO catalyst showed that the catalyst could catalyze dehydrogenation. aldol. dehydration and hydrogenation reactions. Both acidic and basic properties are found on the surface of K-Pd/MnOx-ZrO2-ZnO catalyst, whose multifunctionality with the combination of basic, acid and metal sites may be responsible for the efficiency of the K-PdMnOx-ZrO2-ZnO catalyst. (C) 2004 Elsevier B.V. All rights reserved.
Resumo:
The kinetics of the NO SCR with propane has been studied on a low-exchanged Cu-ZSM-5 catalyst. The study of the kinetics of individual reaction stages (2-nitrosopropane isomerization to acetone oxime and reaction of adsorbed acetone oxime with gaseous NO) has shown that the NO reaction with acetone oxime is the rate-determining stage in the whole chain of transformations leading to the formation of molecular nitrogen in the low-temperature region below 300 C-degrees. The kinetic analysis of the reaction has revealed that at the temperatures above 300(degrees)C propane plays a more important role.