XPS study of oxidation of rhenium metal on γ-Al2O3 support
The oxidation of Re/γ-Al 2 O 3 catalysts, containing 1 and 10 wt% of rhenium, sintered in hydrogen was examined in the temperature range of 20–800 °C. The structures of the catalysts were investigated by XPS spectroscopy, TEM, and O 2 uptake measurements. The low-loaded catalyst comprises metallic particles with sizes of 1–4 nm …
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Discovery, properties and applications of rhenium and its …
The density of rhenium (21.02 g cm –3) is exceeded only by platinum (21.45 g cm –3), iridium (22.56 g cm –3) and osmium (22.59 g cm –3), and its melting point only by tungsten (3420 °C) and carbon (3550 ... The hygroscopic yellowish rhombic (space group P2 1 P 1 P 1) rhenium (VII) oxide, ...
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A first-principles study of oxygen adsorption on Ir(111) surface
The failure mechanism for this iridium-coated rhenium (Ir/Re) structure is diffusion of rhenium into the iridium layer and the subsequent oxidation of the resulting Ir-Re alloy from the inner surface [3], and the grain boundary diffusion is much faster than lattice diffusion [4]. To improve the grain boundary structure of iridium coating, we ...
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Structure of ReOx Clusters Attached on the Ir Metal …
Highly active iridium–rhenium catalyst condensed on silica support for hydrogenolysis of glycerol to 1,3-propanediol. Applied Catalysis B: ... Theoretical studies on the electronic structures and photoelectron spectra of tri-rhenium oxide clusters: Re3On- and Re3On (n=1–6). Spectrochimica Acta Part A: ...
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Electrochemical Dissolution of Iridium and Iridium Oxide …
Iridium-based particles, regarded as the most promising proton exchange membrane electrolyzer electrocatalysts, were investigated by transmission electron microscopy and by coupling of an electrochemical flow cell (EFC) with online inductively coupled plasma mass spectrometry. Additionally, studies using a thin-film rotating disc …
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Iridium-coated rhenium thrusters by CVD (Conference)
@article{osti_5784902, title = {Iridium-coated rhenium thrusters by CVD}, author = {Harding, J T and Kazaroff, J M and Appel, M A}, abstractNote = {Operation of spacecraft thrusters at increased temperature reduces propellant requirements. Inasmuch as propellant comprises the bulk of a satellite's mass, even a small percentage reduction makes …
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Rhenium Suppresses Iridium (IV) Oxide …
Abstract. IrO2 as benchmark electrocatalyst for acidic oxygen evolution reaction (OER) suffers from its low activity and poor stability. Modulating the coordination …
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Rhenium Suppresses Iridium (IV) Oxide Crystallization and …
DOI: 10.1002/smll.202207847 Corpus ID: 256764625; Rhenium Suppresses Iridium (IV) Oxide Crystallization and Enables Efficient, Stable Electrochemical Water Oxidation. @article{Huo2023RheniumSI, title={Rhenium Suppresses Iridium (IV) Oxide Crystallization and Enables Efficient, Stable Electrochemical Water Oxidation.}, …
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Note 92: Yttria Coated Mass Spectrometer Filaments
Yttria (Yttrium Oxide) has been used as a replacement by several manufacturers of leak detectors and ion gauge tubes. SIS has been investigating Yttria (Yttrium Oxide) as a replacement for use in mass …
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Ruthenium(IV) oxide 99.9 trace metals 1
Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others. Ruthenium (IV) oxide 99.9% trace metals basis; CAS Number: 1; EC Number: 234-840-6; Synonyms: Ruthenium dioxide; Linear Formula: RuO2; find Sigma-Aldrich …
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Computational Assessment of the Efficacy of …
Rhenium itself readily oxidizes at high temperatures and the resulting oxide has a low melting point (see Table 1 ). For this reason, in rocket nozzle …
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Recycling and thrifting: the answer to the iridium question in
If we look at today's technology, around 400 kg of iridium is required for every 1 GW of electrolyser capacity. To make sufficient progress towards net-zero targets, the Hydrogen Council estimates PEM capacity would need to increase to around 80 - 100 GW by 2030, assuming a 40% PEM market share. If we used today's technology for all …
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Rhenium Oxide | Formula, Properties & Application
Properties and Structure. Rhenium oxide, particularly in the form of Re 2 O 7, is a pale-yellow, crystalline solid at room temperature. It is notable for its high melting point of 360°C. On the other hand, ReO 3 is a black, volatile solid, and ReO 4– is typically encountered as a colorless, water-soluble anion in various salts.
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(PDF) Oxidation-Protective Iridium and Iridium-Rhodium
Electroforming of iridium, rhenium, molybdenum, niobium and other less common metals is a cost-effective method for the production of rocket combustion chambers as well as other thruster ...
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Direct hydrogenolysis of glycerol into 1,3-propanediol over rhenium …
These data showed that iridium and rhenium in the Ir–ReO x /SiO 2 catalyst were reduced to the metallic state and low-valent metal oxide, respectively. The amount of CO adsorbed on Ir–ReO x /SiO 2 after the reduction at 473 K was 0.07 equiv. to Ir, while 48% of Ir is calculated to be located on the surface of 2.3-nm Ir crystal [17] .
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Morphologies and textures of rhenium coatings
1. Introduction. Rhenium (Re), with a high melting point (3180 °C), high modulus and good ductility, has excellent high-temperature mechanical properties among refractory metals [1], [2], which makes it an ideal high-temperature structural material.An iridium coated rhenium (Ir/Re) combustion chamber has been successfully used in the …
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Molybdenum Oxide-Modified Iridium Catalysts for Selective …
Supported inverse metal–metal oxide catalysts have received significant research interest owing to their effective hydrodeoxygenation (HDO) activity toward biomass substrates, but the high cost of the reported catalysts poses a challenge for commercialization. We present the synthesis of a series of metal–metal oxide catalysts, …
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Long-term high-temperature oxidation of iridium …
Iridium (Ir) is considered as a promising protective coating material on Re, due to its high melting point (2440 °C), low vapor pressure and oxygen permeability at …
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C E H W 4 IbBUSIEBS (IUALISA) CSCZ
Rhenium and iridium, two of the three heaviest metals, hardly would seem suitable as the stuff spacecraft engines are made of. Yet in fact, these obscure metals have made possible a significant improvement in the performance ... all but osmium form a volatile oxide resulting in linear recession of the surface. Recession rates are shown in ...
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Iridium(IV) oxide 99.9 trace metals 1
Iridium oxide is a ceramic material with unique properties like long-term stability, sensitivity, electrochemical catalytic activity, and excellent biocompatibility. It can be formed from Ir metal by different methods like thermal decomposition, reactive sputtering, and electrochemical deposition. It is widely used in bio-electronic devices.
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Evaluation of oxide-coated iridium-rhenium chambers
Iridium-coated rhenium (Ir-Re) provides long life operation of radiation-cooled rockets at temperatures up to 2200 C. Ceramic oxide coatings could be used to increase Ir-Re rocket lifetimes and allow operation in highly oxidizing environments. Ceramic oxide coatings promise to serve as both thermal and diffusion barriers for the iridium layer. Seven …
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Rhenium Material Properties
candidate to replace C-103 is rhenium with iridium used as an oxidation resistant coating. Rhenium has a high melting temperature of 3453 K along with high temperature strength …
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Evidence for the Bifunctional Nature of Pt–Re Catalysts for …
Rhenium substantially promotes the rate of Pt-catalyzed glycerol hydrogenolysis to propanediols and shifts the product selectivity from 1,2-propanediol to a mixture of 1,2 and 1,3-propanediols. This work presents experimental evidence for a tandem dehydration–hydrogenation mechanism that occurs over a bifunctional Pt–Re catalyst. …
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Highly active iridium–rhenium catalyst condensed on
Highly active iridium–rhenium catalyst condensed on silica support for hydrogenolysis of glycerol to 1,3-propanediol. Author links open overlay ... oxide species [9]. The number of Al−OH species was accounted for the high performance of this catalyst. Recently, Qiao et al. found the crystal phase of zirconia significantly affected the ...
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The next step in chemical propulsion: Oxide-iridium/rhenium …
Chemical propulsion systems are currently limited by materials issues. Until recently, the state-of-the-art material for liquid propellant combustion chambers was silicide-coated niobium. However, combustion chamber performance demands have exceeded the capabilities of this material system, requiring development of better materials. The …
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Long Life Testing of Oxide-Coated Iridium Rhenium …
Long Life Testing of Oxide-Coated Iridium/Rhenium Rockets Brian D. Reed Research Center Cleveland, Ohio Prepared for the 31stJoint PropulsionConferenceand Exhibit ... oxide coatings,ZrO2andHfOzwere selectedascoatings The two chambers with thin (less than76 l.tm) for Ir/Re chambers. Theserefractoryoxides havehigher coatings (one …
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Direct hydrogenolysis of glycerol into 1,3-propanediol over rhenium …
Rhenium-oxide-modified supported iridium nanoparticles on silica catalyzes direct hydrogenolysis of glycerol to 1,3-propanediol in an aqueous media. The selectivity to 1,3-propanediol at an initial stage reaches 67 ± 3%. The yield of 1,3-propanediol reaches 38% at 81% conversion of glycerol. The characterization of catalyst and the reactivity ...
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US4444728A
A crucible for preparing a single crystal which comprises an iridium-rhenium alloy comprised of from about 80 to about 99 parts of iridium and from about 1 to about 20 parts of rhenium. ... (the temperature at which the dissociation pressure of the solid oxide equals 1 atmosphere) of iridium oxide is 1100° C. One of the rhenium oxides, ReO 3 ...
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Dynamic rhenium dopant boosts ruthenium oxide …
Heteroatom-doping is a practical means to boost RuO 2 for acidic oxygen evolution reaction (OER). However, a major drawback is conventional dopants have …
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Selective Hydrogenolysis of Glycerol to 1,3-Propanediol over Rhenium …
Request PDF | Selective Hydrogenolysis of Glycerol to 1,3-Propanediol over Rhenium-Oxide-Modified Iridium Nanoparticles Coating Rutile Titania Support | The effect of support in Ir-ReOx catalysts ...
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