نتایج جستجو برای: mixed oxides
تعداد نتایج: 240683 فیلتر نتایج به سال:
The present study investigates the transesterification of corn oil with methanol over two oxides of MgO and ZnO at 65 ͦC and 1 atm. These two catalysts have been prepared via a conventional co-precipitation process. As for MgO, the corresponding mixed metal nitrate solution has been mixed and heated at the presence of urea. ZnO has also been synthesized by co-precipitation of metal acetate at th...
The properties of transition metal oxides are related to the presence of elements with mixed valences. The spectroscopy analysis of the valence states is feasible experimentally, but a spatial mapping of valence states of transition metal elements is a challenge to existing microscopy techniques. In this paper, with the use of valence state information provided by the white lines and near-edge ...
Results from an ongoing study of the high temperature oxidation of intermetallic compounds in the Ti-Al system are presented. The oxidation behavior of alloys based on TiAl (y) has been found to be extremely complex depending on temperature and atmosphere composition. Protective alumina scales are formed in pure O2 up to a critical temperature above which a mixed Ti02/A1203 scale forms and grow...
Although chemically very simple, Fe2O3 is known to undergo a series of enigmatic structural, electronic and magnetic transformations at high pressures and high temperatures. So far, these transformations have neither been correctly described nor understood because of the lack of structural data. Here we report a systematic investigation of the behaviour of Fe2O3 at pressures over 100 GPa and te...
A simple and efficient route to prepare supported nanocrystalline oxides is presented. The synthesis procedure, i.e. in situ autocombustion of a glycine complex, allows the production of nanocrystals in a porous matrix presenting larger pore size. An example of successful formation of 2-5 nm nanocrystals is given for a single oxide (Fe(2)O(3)), a mixed-oxide structure (LaCoO(3) perovskite-type)...
Cobalt oxides, such as Co3O4 and CoO, have received increased attention as potential anode materials for rechargeable lithium-ion batteries (LIBs) owing to their high theoretical capacity. Nanostructure engineering has been demonstrated as an effective approach to improve the electrochemical performance of electrode materials for LIBs. In this review, we summarize recent development in the rati...
We present an overview on the development of various mixed conducting perovskite-type related structure metal oxides and other crystal structures, composite cathodes for advanced solid oxide fuel cells.
Heterometallic oxides are used as materials in many applications, e.g. from ferroelectrics to superconductors. Making these compounds usually requires high temperatures and long reaction times. Molecular precursors may contribute to render their processing shorter and accessible at lower temperatures, thus cheaper in energy and time. In this review article, different approaches toward oxide mat...
Developing earth-abundant, active and stable electrocatalysts which operate in the same electrolyte for water splitting, including oxygen evolution reaction and hydrogen evolution reaction, is important for many renewable energy conversion processes. Here we demonstrate the improvement of catalytic activity when transition metal oxide (iron, cobalt, nickel oxides and their mixed oxides) nanopar...
Ferroelectric solar cells based on ferroelectric oxides have attracted significant attention owing to many unique advantages, such as the switchable photocurrent and photovoltage, and the above bandgap open circuit voltages. However, the small photocurrent densities of the typical ferroelectric solar cells greatly limit their photovoltaic performance. In this report, we experimentally revealed ...
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