نتایج جستجو برای: metal oxides
تعداد نتایج: 213121 فیلتر نتایج به سال:
The paper contrasts the main drawbacks of silica based packings such as their relative thermal and chemical instability with excellent stability of metal oxides. The paper concerns mainly ZrO2, TiO2 and Al2O3. Surface chemistry of the oxides is however very different from that of silica. Ability of the oxides to ionand ligand-exchange is discussed from a chromatographic point of view.
Aspects of the chemistry of selected metal fluorides, which are pertinent to their real or potential use as Lewis acidic, heterogeneous catalysts, are reviewed. Particular attention is paid to β-aluminum trifluoride, aluminum chlorofluoride and aluminas γ and η, whose surfaces become partially fluorinated or chlorinated, through pre-treatment with halogenating reagents or during a catalytic rea...
The performance of metal oxides as redox materials is limited by their oxygen conductivity and thermochemical stability. Predicting these properties from the electronic structure can support the screening of advanced metal oxides and accelerate their development for clean energy applications. Specifically, reducible metal oxide catalysts and potential redox materials for the solar-thermochemica...
The molecular structures and reactivity of tantalum oxide-supported metal oxide (V2O5, Nb2O5, CrO3, MoO3, WO3, and Re2O7) catalysts were determined by Raman spectroscopy and the methanol oxidation chemical probe reaction, respectively. The metal oxides form a twodimensional surface metal oxide overlayer on the tantalum oxide support. Under ambient conditions, the hydrated surface metal oxide sp...
Ammonium Perchlorate (AP) is one of the most important oxidizer in composite solid propellants. Therefore, synthesis and application of nanoparticles as catalyst for improving thermal decomposition of AP is an important issue in catalysis research. There are a great many nanomaterials for the thermal decomposition of AP such as nano metal particles, metal oxides, metals salts, metallic composit...
Materials synthesis often provides opportunities for innovation. We demonstrate a general low-temperature (260°C) molten salt electrodeposition approach to directly electroplate the important lithium-ion (Li-ion) battery cathode materials LiCoO2, LiMn2O4, and Al-doped LiCoO2. The crystallinities and electrochemical capacities of the electroplated oxides are comparable to those of the powders sy...
New and optimized metal-oxide thin films for both transparent-conductor and antireflection coatings have the potential to significantly improve photovoltaic devices. One approach to this task of discovery and improvement is to use a parallel optimization, i.e., a combinatorial, approach. Using internal seed funds, we have developed the initial deposition, characterization and analysis tools nec...
The results of a mechanistic study using ab initio theoretical methods are used to outline plausible mechanistic sequences for alkane, alcohol, and alkene oxidation by chromyl and molybdyl chlorides. We suggest that the second oxo group is intimately involved in the reaction sequence. This spectator oxo group is suggested to play a central role in stabilizing critical intermediates in these rea...
four different alkaline earth metal oxides i.e. mgo, cao, sro and bao were used as heterogeneous catalysts for biodiesel production from palm oil. effects of critical process variables i.e. reaction time, methanol to oil ratio and temperature were investigated. the results were then fitted to a historical design to study the analysis of variance (anova), to characterize interactions between var...
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