尽管为将合成气直接转化为液体燃料做出了巨大努力,但选择性仍然是一个挑战,特别是对于辛烷值高且芳族化合物含量低的高品质汽油。在此,我们显示具有一维十元环(10MR)通道结构的沸石(如SAPO-11和ZSM-22)与锌和锰基金属氧化物(Zn a Mn b O x)结合使用时,直接从合成气中选择性合成汽油范围的碳氢化合物C 5 –C 11。碳氢化合物中汽油的选择性达到76.7%,而CH 4仅为2.3%CO转化率为20.3%。异链烷烃与正链烷烃之比高达15,研究辛烷值估计为92。此外,汽油中芳族化合物的含量低至16%。Zn a Mn b O x的组成和结构在确定总体活性中起重要作用。该方法构成了一种潜在的技术,可以通过合成气从多种碳资源一步合成高辛烷值的环保汽油。
Controlled Synthesis, Characterizations and Structural-Properties of Micro-Flowers, Pine-Cone, Core–Shell and Liver-Like Micro-Architecture of Crystalline ZnMn<SUB>2</SUB>O<SUB>4</SUB>
作者:Qurat-ul-ain Javed、Fengping Wang、Arbab Mohammad Toufiq
DOI:10.1166/jnn.2013.7420
日期:2013.4.1
The conspicuous ZnMn2O4 micro-structures have been synthesized by hydrothermal method by using Mn3O4 and Zn powder as precursors. The micro-structures of the ZnMn2O4 could be tuned by changing the reaction time only in the reaction system. The final products have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and the Raman spectroscopy. Room temperature Raman spectroscopy investigation indicates that the synthesized micro-structures have strong fundamental vibrational modes. The intensity of the vibrational modes varied with change in the reaction time in the synthesized products of ZnMn2O4. The mechanism of this peculiar Raman property was analyzed.
Site occupancy determination for manganese in some spinel-type oxides by Kβ X-ray fluorescence spectra
作者:Hiromi Eba、Kenji Sakurai
DOI:10.1016/j.jssc.2004.10.011
日期:2005.1
determination for manganese spinels by analyzing Kβ X-ray fluorescencespectra, which are essentially sensitive to chemical environments such as oxidation and/or coordination numbers. Instead of looking at peak positions and/or shapes of the spectra, the intensity ratios of Kβ′ satellite and Kβ5 lines were investigated in detail. It has been found that the spectra are apparently classified depending on the manganese
Enhanced photoelectrochemical and photocatalytic properties of Mg-doped ZnMn2O4
作者:R. Gherbi、M. Benamira、Y. Bessekhouad
DOI:10.1016/j.jallcom.2020.156797
日期:2021.1
revealed that the stability against photocorrosion increased with Mg-doping. In addition, the photocurrent (Jph) increased from 8.33 10-2 to 75.01 10-2 mA cm-2. On the other hand, the electrochemical impedance spectroscopy revealed that the recombination through the semiconductor limited the efficiency. The photoactivity gradually increased with increasing the dopant content, and 72% of photodegradation
(TEM) techniques. The electrochemicalproperties of the sample are investigated by battery testing system. The influences of different precipitants on its structure, morphology and the electrochemicalproperties are discussed. The results show that the morphology of expected compound is depended on different precipitants. When tested as anode material for lithium ion battery, the ZnMn2O4 sample obtained
Tuning the Electrocatalytic Water Oxidation Properties of AB<sub>2</sub>O<sub>4</sub> Spinel Nanocrystals: A (Li, Mg, Zn) and B (Mn, Co) Site Variants of LiMn<sub>2</sub>O<sub>4</sub>
作者:Clyde W. Cady、Graeme Gardner、Zachary O. Maron、Maria Retuerto、Yong Bok Go、Shreeda Segan、Martha Greenblatt、G. Charles Dismukes
DOI:10.1021/acscatal.5b00265
日期:2015.6.5
Transition metal oxides containing cubic B4O4 subcores are noted for their catalytic activity in water oxidation (OER). We synthesized a series of ternary spineloxides, AB2O4, derived from LiMn2O4 by either replacement at the tetrahedral A site or Co substitution at the octahedral B site and measured their electrocatalytic OER activity. Atomic emission and powder X-ray diffraction confirmed spinel structure
含有立方B 4 O 4子核的过渡金属氧化物因其在水氧化(OER)中的催化活性而闻名。我们合成了一系列三元尖晶石氧化物AB 2 O 4,它们通过在四面体A位点处取代或在八面体B位处Co取代而衍生自LiMn 2 O 4,并测量了它们的电催化OER活性。原子发射和粉末X射线衍射证实了尖晶石的结构类型和纯度。OER的弱活化在A位取代后发生:Zn 2+ > Mg 2+ > A空位> Li +=0。Zn和Mg置换伴随(1)Mn(IV)到Mn(III)的B位转化,导致[Mn 4 O 4 ] 4+核相对于LiMn 2 O膨胀并具有更高的对称性4(导致核的更大的柔韧性和更低的扭曲变形障碍),以及(2)Mn(III)/ IV的电化学氧化电势增加0.15-0.2 V,从而产生更强的水氧化驱动力。逐步取代的Mn(III / IV)的Co(III)在B位点(的LiMn 2- X钴X Ò 4,0≤ X ≤1.5)两者的symmetrizes