Topic
Oxygen
About: Oxygen is a research topic. Over the lifetime, 48149 publications have been published within this topic receiving 1113788 citations. The topic is also known as: O & Oxygen.
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TL;DR: In this article, the effect of AQ surface concentration on the kinetics of oxygen reduction has been investigated and the rate constant of the chemical reaction between semiquinone radical anion of AQ and molecular oxygen has been determined.
214 citations
TL;DR: In this article, an equivalent circuit analysis on a mixed conductor electrode/solid oxide electrolyte system was performed on a dense film of La 0.6 Sr 0.4 CoO 3-δ deposited on a sintered plate of Ce 0.9 Gd 0.1 O 1.95 by a laser ablation method.
Abstract: Equivalent circuit analysis was undertaken on a mixed conductor electrode/solid oxide electrolyte system. In a limited case where surface reaction is the predominant rate-controlling process, the equivalent circuit was simplified to parallel connection of a resistor (surface reaction resistance) and a capacitor (chemical capacitance due to oxygen nonstoichiometry). Equilibrium oxygen vacancy concentration was correlated with the chemical capacitance. The model was applied to a dense film of La 0.6 Sr 0.4 CoO 3-δ deposited on a sintered plate of Ce 0.9 Gd 0.1 O 1.95 by a laser ablation method. Frequency response of the electrochemical impedance was measured under dc bias at 873-1073 K in O 2 -Ar gas mixtures. The observed capacitance was extremely large, e.g., around 0.1 to I F cm -2 for the 1.5 μm thick film. The oxygen vacancy concentration in the film was calculated from the capacitance and compared with the literature data measured by thermogravimetry. The film was found to show smaller oxygen nonstoichiometry. The enthalpy for oxygen vacancy formation in the film was about 40 kJ mol -1 larger than the bulk.
214 citations
TL;DR: In this article, Zirconium-doped perovskite-type membrane materials of BaCo0.4Fe0.6O3−δ with mixed oxygen ion and electron conductivity were synthesized through combining citric and EDTA acid complexes.
214 citations
TL;DR: In this article, a set of oxygen carrier materials synthesized from manganese oxides mixed with iron, nickel, and silicon oxides are evaluated in terms of their ability to release oxygen and to be regenerated with oxygen and demonstrated methane conversion in a quartz fluidized bed batch reactor at 810, 850 and 900 °C.
Abstract: Chemical-looping with oxygen uncoupling (CLOU) is a developing technology, which allows for inherent separation of carbon dioxide during combustion of gaseous and solid fuels. In contrast to the related chemical-looping combustion technology (CLC), where gaseous or gasified fuels react directly with oxygen carrier materials, CLOU utilizes oxygen carriers capable of releasing gaseous oxygen, provided appropriate thermal conditions exist in the fuel reactor, whereupon fuel reacts with the released oxygen. The oxygen carriers are thereafter regenerated by oxidation in the air reactor. In this work, a set of oxygen carrier materials synthesized from manganese oxides mixed with iron, nickel, and silicon oxides are evaluated in terms of their ability to release oxygen and to be regenerated with oxygen and in terms of demonstrated methane conversion in a quartz fluidized bed batch reactor at 810, 850, and 900 °C. The results demonstrate that two Mn/Fe oxygen carriers and one Mn/Ni oxygen carrier have both oxygen release characteristics and high reactivities with methane.The Mn/Fe oxygen carrier synthesized at 1100 °Cwas additionally shown to have an increasing methane conversion on a long-term basis, which opens for a possibility to use Mn/Fe oxygen carriers in time-extended large-scale chemical-looping operations.
214 citations
TL;DR: In this article, it was shown that the initial selectivity of the reaction is determined by the bond strength and chemical nature of the adsorbed oxygen and the inability to activate the carbon-hydrogen bond.
213 citations