Topic
Reducing atmosphere
About: Reducing atmosphere is a research topic. Over the lifetime, 3440 publications have been published within this topic receiving 39175 citations.
Papers published on a yearly basis
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Papers
TL;DR: A redox-sensitive calibration to determine the oxidation state of Hadean magmatic melts is reported, finding that the melts have average oxygen fugacities that are consistent with an oxidation state defined by the fayalite–magnetite–quartz buffer, similar to present-day conditions.
Abstract: Magmatic outgassing of volatiles from Earth's interior probably played a critical part in determining the composition of the earliest atmosphere, more than 4,000 million years (Myr) ago. Given an elemental inventory of hydrogen, carbon, nitrogen, oxygen and sulphur, the identity of molecular species in gaseous volcanic emanations depends critically on the pressure (fugacity) of oxygen. Reduced melts having oxygen fugacities close to that defined by the iron-wustite buffer would yield volatile species such as CH(4), H(2), H(2)S, NH(3) and CO, whereas melts close to the fayalite-magnetite-quartz buffer would be similar to present-day conditions and would be dominated by H(2)O, CO(2), SO(2) and N(2) (refs 1-4). Direct constraints on the oxidation state of terrestrial magmas before 3,850 Myr before present (that is, the Hadean eon) are tenuous because the rock record is sparse or absent. Samples from this earliest period of Earth's history are limited to igneous detrital zircons that pre-date the known rock record, with ages approaching ∼4,400 Myr (refs 5-8). Here we report a redox-sensitive calibration to determine the oxidation state of Hadean magmatic melts that is based on the incorporation of cerium into zircon crystals. We find that the melts have average oxygen fugacities that are consistent with an oxidation state defined by the fayalite-magnetite-quartz buffer, similar to present-day conditions. Moreover, selected Hadean zircons (having chemical characteristics consistent with crystallization specifically from mantle-derived melts) suggest oxygen fugacities similar to those of Archaean and present-day mantle-derived lavas as early as ∼4,350 Myr before present. These results suggest that outgassing of Earth's interior later than ∼200 Myr into the history of Solar System formation would not have resulted in a reducing atmosphere.
566 citations
TL;DR: In this paper, the authors used excess tin iodide (SnI2) in Sn-based halide perovskite solar cells (ASnI3, A = Cs, methylammonium, and formamidinium Tin iodide) combined with a reducing atmosphere to stabilize the Sn2+ state.
Abstract: Sn-based halide perovskite materials have attracted tremendous attention and have been employed successfully in solar cells. However, their high conductivities resulting from the unstable divalent Sn state in the structure cause poor device performance and poor reproducibility. Herein, we used excess tin iodide (SnI2) in Sn-based halide perovskite solar cells (ASnI3, A = Cs, methylammonium, and formamidinium tin iodide as the representative light absorbers) combined with a reducing atmosphere to stabilize the Sn2+ state. Excess SnI2 can disperse uniformly into the perovskite films and functions as a compensator as well as a suppressor of Sn2+ vacancies, thereby effectively reducing the p-type conductivity. This process significantly improved the solar cell performances of all the ASnI3 materials on mesoporous TiO2. Optimized CsSnI3 devices achieved a maximum power conversion efficiency of 4.81%, which is the highest among all inorganic Pb-free perovskite solar cells to date.
324 citations
TL;DR: In this paper, the effect on ceramic products of firing conditions in the presence of abundant organic matter is assessed by reproducing two ancient firing techniques: pit firing, characterised by a high heating rate and short residence time in a reducing atmosphere; kiln firing, with a low heating rate, and long residence time, in an oxidising atmosphere.
323 citations
Patent•
12 Nov 2002TL;DR: In this paper, a post deposition treatment that densifies the film in a reducing atmosphere to enhance stability if the film is to be cured ex-situ was proposed. But this method is not suitable for silicon-oxygen-carbon low dielectric constant films that have been deposited at low temperature.
Abstract: A method for providing a dielectric film having enhanced adhesion and stability. The method includes a post deposition treatment that densifies the film in a reducing atmosphere to enhance stability if the film is to be cured ex-situ. The densification generally takes place in a reducing environment while heating the substrate. The densification treatment is particularly suitable for silicon-oxygen-carbon low dielectric constant films that have been deposited at low temperature.
282 citations
TL;DR: The observed influence of oxygen vacancies on the activity and selectivity of photoinduced reactions may lead to new routes toward the design of highly selective photocatalysts.
Abstract: Conventional TiO2-based photocatalysts oxidize NOx to nitrate species, which do not spontaneously desorb and therefore deactivate the catalyst. We show that the selectivity of this reaction can be changed by creating a large concentration of oxygen vacancies in TiO2 nanoparticles through thermal reduction in a reducing atmosphere. This results in the photoreduction of nitric oxide (NO) to N2 and O2, species which spontaneously desorb at room temperature. The activity of the photoreduction reaction can be greatly enhanced by doping the TiO2 nanoparticles with Fe3+, an acceptor-type dopant that stabilizes the oxygen vacancies. Moreover, the photoinduced reduction of Fe3+ to Fe2+ provides a recombination pathway that almost completely suppresses the formation of NO2 and thus enhances the selectivity of the reaction for N2 formation. Gas chromatography confirms that N2 and O2 are formed in a stoichiometric ratio, and the activity for NO decomposition is found to be limited by the concentration of oxygen vacan...
265 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 10 |
| 2024 | 12 |
| 2023 | 34 |
| 2022 | 81 |
| 2021 | 64 |
| 2020 | 84 |