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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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Journal ArticleDOI
TL;DR: In this paper, an electron acceptor (Fe3+) which is part of a reversible redox couple was described for the photo-oxidation of water with visible light, and the formal quantum efficiency for oxygen production at 405 nm was (3.1 ± 0.1)× 10−3 mol ein−1.
Abstract: WO3 powder photosensitized the oxidation of water by Fe3+ ions with blue light (400–450 nm). The formal quantum efficiency for oxygen production at 405 nm was (3.1 ± 0.1)× 10–3 mol ein–1. Oxygen production was partially inhibited by Fe2+, oxygen and high concentrations of Fe3+(> 10–2 mol dm–3). Depositing RuO2 on to the semiconductor powder produced a moderate increase in the rate of oxygen production, while deposits of Pt, Rh and Ru lead to a decrease in the rate of oxygen formation. Unlike most of the artificial systems which have been described for the photo-oxidation of water with visible light, this system operates with an electron acceptor (Fe3+) which is part of a reversible redox couple (Fe3+/Fe2+).

173 citations

Journal ArticleDOI
TL;DR: DFT predictions of the energetics support the experimental observation that the reduced surfaces are energetically more favorable than the unreduced surfaces for oxygen adsorption and reduction.
Abstract: Interactions between O(2) and CeO(2) are examined experimentally using in situ Raman spectroscopy and theoretically using density-functional slab-model calculations. Two distinct oxygen bands appear at 825 and 1131 cm(-1), corresponding to peroxo- and superoxo-like species, respectively, when partially reduced CeO(2) is exposed to 10 % O(2). Periodic density-functional theory (DFT) calculations aid the interpretation of spectroscopic observations and provide energetic and geometric information for the dioxygen species adsorbed on CeO(2). The O(2) adsorption energies on unreduced CeO(2) surfaces are endothermic (0.91

173 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared the gross and net heat of combustion calculated from polymer enthalpies of formation and oxygen consumption thermochemistry were within 5% of the experimental values from oxygen bomb calorimetry.
Abstract: The heats of combustion for 49 commercial and developmental polymers of known chemical structure were determined using an oxygen bomb calorimeter according to standard methods. The experimental results were compared with thermochemical calculations of the net heat of combustion from oxygen consumption and the gross heat of combustion from group additivity of the heats of formation of products and reactants. The polymers examined were thermally stable, char forming thermoplastics and thermoset resins containing a significant degree of aromaticity and heteroatoms including — nitrogen, sulphur, phosphorus, silicon, and oxygen in linear and heterocyclic structures. The gross and net heats of combustion calculated from polymer enthalpies of formation and oxygen consumption thermochemistry were within 5% of the experimental values from oxygen bomb calorimetry. The heat released by combustion per gram of diatomic oxygen consumed in the present study was E=13.10±0.78 kJ/gO2 for polymers tested (n=48). This value is indistinguishable from the universal value E13.1 kJ/gO2 used in oxygen consumption combustion calorimetry. Published in 2000 by John Wiley & Sons Ltd.

173 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the catalytic systems for the direct production of hydrogen peroxide from hydrogen and oxygen, and the factors which make a successful process identified, such as low metal loadings, an organic co-solvent (such as ethanol) and reduced palladium as catalytic metal all lead to good activity and selectivity.
Abstract: Catalytic systems for the direct production of hydrogen peroxide from hydrogen and oxygen are investigated, and the factors which make a successful process identified. The use of low metal loadings, an organic co-solvent (such as ethanol) and reduced palladium as the catalytic metal all lead to good activity and selectivity.

173 citations

Journal ArticleDOI
TL;DR: In this paper, an uncommon oxygen absorption/desorption behavior is reported for the cation-stoichiometric cobalt oxide, YBaCo4O7, structurally composed of two kinds of layers of corner-sharing CoO4 tetrahedra.
Abstract: An uncommon oxygen absorption/desorption behavior is reported for the cation-stoichiometric cobalt oxide, YBaCo4O7, structurally composed of two kinds of layers of corner-sharing CoO4 tetrahedra. We have found that YBaCo4O7+δ absorbs and desorbs oxygen up to δ ≈ 1.5 in a narrow temperature range below 400 °C. The oxygen uptake/release process is highly reversible, being controlled by both temperature and oxygen partial pressure. Such a large low-temperature oxygen-content tunability is of great promise in regard to applications related to, for example, oxygen storage. Materials with similar characteristics are, to a large degree, lacking today.

173 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20233,516
20226,670
20211,229
20201,164
20191,190
20181,153