Reaction Of Oxygen Research Articles

Chemical looping for upgrading light alkanes: oxygen carriers, reaction kinetics, and reactor design

Chemical looping for upgrading light alkanes: oxygen carriers, reaction kinetics, and reactor design

Cobalt Phosphide Decorating Metallic Cobalt With a Nitrogen‐Doped Carbon Nano‐Shell Surpasses Platinum Group Metals for Oxygen Electrocatalysis Applications

ABSTRACTIt has been a long‐standing challenge to cultivate capable and resilient oxygen electrocatalysts with higher activity, low price, and long lifetime to replace the commonly used platinum group metals, i.e., Pt for oxygen reduction reaction (ORR) and RuO2/IrO2 for oxygen evolution reaction (OER). This work presents a promising approach to address the challenges associated with oxygen electrocatalysis by introducing a cobalt phosphide/metallic cobalt (Co2P/Co) core wrapped in a nitrogen‐doped conductive carbon (CN) nano‐shell, demonstrated as Co2P/Co@NC. The strong chemical bonding between metallic cobalt and phosphorus, nitrogen and conductive carbon contributes to the enhanced conductivity and stability of the electrocatalyst. The nitrogen doping in the carbon shell provides additional Co–N active sites, which are crucial for ORR activity. Co2P/Co@NC demonstrates promising activity and stability compared to noble metals such as Pt for ORR in an alkaline medium. This suggests its potential as a cost‐effective alternative to Pt‐based catalysts. Further, due to factors such as strong cobalt‐phosphide bonding, high cobalt oxidation states and excellent conductivity of the nitrogen‐doped carbon shell, the Co2P/Co@NC outperforms noble metal oxides like iridium dioxide (IrO2) and ruthenium dioxide (RuO2) for OER. Co2P/Co@NC exhibits a low potential difference of 0.63 V, which is among the lowest reported for bifunctional electrocatalysts capable of both ORR and OER. Overall, the described strategy offers a promising avenue for developing efficient, low‐cost and stable electrocatalysts for oxygen reactions, which are crucial for various electrochemical energy conversion and storage technologies, such as fuel cells and metal–air batteries.

Influence of platinum content on semiconductor and electrochemical properties of materials based on titanium suboxides

The effect of platinum content on the surface morphology, phase composition and electrochemical properties of materials based on titanium suboxides was investigated. Titanium suboxides are formed at the stage of coating reduction under cathodic polarization, which allows the formation of a porous developed surface for electrodeposition of catalytic platinum layers. The main allotropic modification of TiOx in the studied composite materials is anatase, which contains particles of elemental titanium and platinum. The investigated materials are highly doped semiconductors with a high concentration of charge carriers. With an increase in the platinum content, an extreme dependence of the potential of flat zones is observed, which is associated with the formation of a composite material. The electrocatalytic activity was studied in the reactions of oxygen and hydrogen evolution. The overvoltage of oxygen production on platinum-containing materials is much lower than on the TiOx electrode. The slope of the linear dependence of the potential on the current density decreases with an increase in platinum content. The Tafel slope for the studied materials in the hydrogen evolution reaction was 160 mVdec–1 for coatings containing 0.25 mgcm–2 Pt; whereas it was equal to 42 and 43 mVdec–1 for electrodes with 0.5 and 2 mgcm–2 Pt, respectively.

Prediction of perovskite oxygen vacancies for oxygen electrocatalysis at different temperatures

Efficient catalysts are imperative to accelerate the slow oxygen reaction kinetics for the development of emerging electrochemical energy systems ranging from room-temperature alkaline water electrolysis to high-temperature ceramic fuel cells. In this work, we reveal the role of cationic inductive interactions in predetermining the oxygen vacancy concentrations of 235 cobalt-based and 200 iron-based perovskite catalysts at different temperatures, and this trend can be well predicted from machine learning techniques based on the cationic lattice environment, requiring no heavy computational and experimental inputs. Our results further show that the catalytic activity of the perovskites is strongly correlated with their oxygen vacancy concentration and operating temperatures. We then provide a machine learning-guided route for developing oxygen electrocatalysts suitable for operation at different temperatures with time efficiency and good prediction accuracy.

Measurement of γ-Rays Generated by Neutron Interaction with 16O at 30 MeV and 250 MeV

Abstract Deep understanding of $\gamma$-ray production from the fast neutron reaction in water is crucial for various physics studies at large-scale water Cherenkov detectors. We performed test experiments using quasi-mono energetic neutron beams ($E_n = 30$ and 250 MeV) at Osaka University’s Research Center for Nuclear Physics to measure $\gamma$-rays originating from the neutron–oxygen reaction with a high-purity germanium detector. Multiple $\gamma$-ray peaks which are expected to be from excited nuclei after the neutron–oxygen reaction were successfully observed. We measured the neutron beam flux using an organic liquid scintillator for the cross section measurement. With a spectral fitting analysis based on the tailored $\gamma$-ray signal and background templates, we measured cross sections for each observed $\gamma$-ray component. The results will be useful to validate neutron models employed in ongoing and future water Cherenkov experiments.

Stereoelectronic Tuning of Bioinspired Nonheme Iron(IV)-Oxo Species by Amide Groups in Primary and Secondary Coordination Spheres for Selective Oxygenation Reactions.

Two mononuclear iron(II) complexes, [(6-amide2-BPMEN)FeII](OTf)2 (1) and [(6-amide-Me-BPMEN)FeII(OTf)](OTf) (2), supported by two BPMEN-derived (BPMEN = N1,N2-dimethyl-N1,N2-bis(pyridine-2-yl-methyl)ethane-1,2-diamine) ligands bearing one or two amide functionalities have been isolated to study their reactivity in the oxygenation of C-H and C═C bonds using isopropyl 2-iodoxybenzoate (iPr-IBX ester) as the oxidant. Both 1 and 2 contain six-coordinate high-spin iron(II) centers in the solid state and in solution. The 6-amide2-BPMEN ligand stabilizes an S = 1 iron(IV)-oxo intermediate, [(6-amide2-BPMEN)FeIV(O)]2+ (1A). The oxidant (1A) oxygenates the C-H and C═C bonds with a high selectivity. Oxidant 1A, upon treatment with 2,6-lutidine, is transformed into another oxidant [{(6-amide2-BPMEN)-(H)}FeIV(O)]+ (1B) through deprotonation of an amide group, resulting in a stronger equatorial ligand field and subsequent stabilization of the triplet ground state. In contrast, no iron-oxo species could be observed from complex 2 and [(6-Me2-BPMEN)FeII(OTf)2] (3) under similar experimental conditions. The iron(IV)-oxo oxidant 1A shows the highest A/K selectivity in cyclohexane oxidation and 3°/2° selectivity in adamantane oxidation reported for any synthetic nonheme iron(IV)-oxo complexes. Theoretical investigation reveals that the hydrogen bonding interaction between the -NH group of the noncoordinating amide group and Fe═O core smears out the equatorial charge density, reducing the triplet-quintet splitting, and thus helping complex 1A to achieve better reactivity.

Effects of zirconium diboride addition on porosity reduction in laser metal deposition of tungsten carbide–cobalt cermet material

Laser metal deposition of tungsten carbide–cobalt (WC-Co) cermet material is a promising means of improving the wear resistance of metal products. However, laser metal deposition of WC-Co has constraints on its practical use because a clad bead of WC-Co often includes numerous gas pores. Earlier studies have found CO gas generation in a molten pool by reaction of carbon and oxygen to be the main cause of gas porosity in a WC-Co clad bead. Preventing the gas reaction is important to obtain clad beads with few pores. The addition of elements with strong affinity for oxygen, such as aluminum, was found to be effective for porosity reduction in a clad bead. However, the addition of highly reactive pure aluminum particles on WC-Co powder presents some difficulties for industrial use. For this study, zirconium diboride (ZrB2), a chemically stable compound, was used as an additive to WC-Co powder. After WC-Co powder with adhered ZrB2 particles was prepared using a wet granulation process, laser metal deposition was conducted. Zirconium stemming from the dissolution of ZrB2 in the molten pool was found to have the effect of trapping oxygen elements as solid zirconium oxides. Consequently, gas generation in the molten pool by the reaction of carbon and oxygen was restrained. Clad beads having few pores and fine microstructures were obtained. Observations of the molten pool behavior taken using a high-speed camera indicated that ZrB2 addition drastically improves process stability compared to processes using conventional WC-Co powder.

The Inclusion Characteristics and Mechanical Properties of M2 High-Speed Steel Treated with a Vacuum Carbon Deoxidation Process

The oxygen content of M2 high-speed steel has not been intentionally controlled in industrial production through secondary refinement in vacuum furnaces. However, a lower oxygen content has a significant effect on the cleanliness, toughness, and addition of rare-earth elements to M2 high-speed steel. The changes in total oxygen content controlled by vacuum carbon deoxidation (VCD) treatment and inclusion evolution were investigated in M2 high-speed steel to understand the effects of carbon on dissolved oxygen and oxides in the carbon–oxygen (C-O) reaction process. Furthermore, the microstructure and properties of M2 high-speed steel caused by vacuum insulation and the role of reducing oxygen content in rare-earth alloying were briefly demonstrated. The results showed that the [O%] decreased from 30 ppm to 3 ppm in a vacuum at holding times above 25 min through the C-O reaction, leading to an inclusion reduction of approximately 70%. In the case of [O%] = 3 ppm in M2 high-speed steel, the addition of rare-earth elements has a greater effect on the inclusion characteristics. Lowering the oxygen content of M2 high-speed steel improves cleanliness and plays a significant role in rare-earth alloying.

Synergistic impact of nano-supramolecular coordination polymer based on cadmium, ethyl nicotinate and thiocyanate ligands as efficient catalyst to remove harmful elements from wastewater.

Under ultrasonication, cadmium nitrate tetrahydrates, ethyl nicotinate (EN), and potassium thiocyanate as connecting ligand self-assembled to form the nanosized supramolecular coordination polymer (NSCP1) and the crystalline supramolecular coordination polymer (SCP1) [Cd(EN)2(SCN)2]. Single crystal SCP1 X-ray diffraction (XRD) revealed that CdII has an octahedral shape. The network structure of SCP1 is composed of chair conformation cyclic [Cd2(SCN)2] n building blocks that form a one dimensional (1D) chain with bilaterally coordinated EN. The 1D-chain is joined to the other by extensive hydrogen bonds, which arrange the chains into a three-dimensional network. By stacking π-π, the strands are fluttering the three-dimensional (3D) network even more. Several structural characterization methods and spectral analyses were used to analyze SCP1 and NSCP1. The heterogeneous catalysts SCP1 and NSCP1 have been shown to display exceptionally strong catalytic activity against the breakdown of the designated contaminant, indigo carmine (IC) color in very short durations under ultraviolet (UV) or ultrasonic wave conditions. The photoluminescence probing approach was utilized to determine the reactive oxygen species and reaction process using the disodium salt of terephthalic acid.

Why We Eat Calories: A Plurality Metaphor of Energy in Scientific Disciplines

AbstractIn the Next Generation Science Standards, energy is considered a “crosscutting concept” that bridges disciplinary boundaries and unites scientific disciplines. I examine how energy is represented in physics, biology, and chemistry contexts, using the reaction of molecular oxygen with sugar as an exemplar, and argue that disciplines disagree in how they represent the origin of energy that drives this process. In particular, while biology tends to locate energy as initially in the sugar molecule, chemistry locates the energy in molecular oxygen, and physics models energy as in the field between the molecules. That is to say, biology describes us as eating calories, chemistry as inhaling calories, and physics invents an abstract object (the field) as the container for energy. I then show how the conceptualizations made in each discipline stem from core disciplinary commitments, models, and concepts that structure what “counts” as an explanation. This conceptual plurality, then, is essential to disciplinary meaning. While such a pluralistic conceptualization appears to be contrary to scientific epistemology that prioritizes coherence and cognitive models that rely on unitary structures for transfer, I draw on recent research to argue that neither concern is fully founded. Finally, I suggest that building bridges between these contrasting conceptualizations may come later, in response to interdisciplinary questions and frameworks.

Strategies to improve oxidation resistance of MgO–C refractories by decreasing oxygen potential through MgSiN2

AbstractMgO–C refractories are of paramount importance in the converter side blowing system, requiring outstanding oxidation resistance under harsh conditions including high temperature, oxygen atmosphere, and high‐speed airflow. In this study, MgSiN2 phase reconstruction was used to improve the oxidation resistance of MgO–C refractories, as well as the mechanical properties and oxidation resistance of MgO–C refractories were evaluated. The results indicated that the cold modulus of rupture of the sample with 9 wt% MgSiN2 was increased by 93.3% compared with the MgO–C refractories without MgSiN2. After oxidation tests, the oxidation index and rate constant (k) of the sample with 9 wt% MgSiN2 were reduced by 38.9% and 35.3%. Furthermore, incorporating MgSiN2 facilitated the formation of layered dense structures consisting of plate‐like Mg‐Sialon and MgO–Mg2SiO4–MgAl2O4. This structural optimization effectively inhibited oxygen diffusion and reaction within the material, resulting in gradual oxygen potential mitigation.

Enhancing Reversibility and Kinetics of Anionic Redox in O3‐NaLi1/3Mn2/3O2 through Controlled P2 Intergrowth

AbstractAnionic redox chemistry can surpass theoretical limits of conventional layered oxide cathodes in energy density. A recent model system of sodium‐ion batteries, O3‐NaLi1/3Mn2/3O2, demonstrated full anionic redox capacity but is limited in reversibility and kinetics due to irreversible structural rearrangement and oxygen loss. Solutions to these issues are missing due to the challenging synthesis. Here, we harness the unique structural richness of sodium layered oxides and realize a controlled ratio of P2 structural intergrowth in this model compound with the overall composition maintained. The resulted O3 with 27 % P2 intergrowth structure delivers an excellent initial Coulombic efficiency of 87 %, comparable to the state‐of‐the‐art Li‐rich NMCs. This improvement is attributed to the effective suppression of irreversible oxygen release and structural changes, evidenced by operando Differential Electrochemical Mass Spectroscopy and X‐ray Diffraction. The as‐prepared intergrowth material, based on the environmentally benign Mn, exhibits a reversible capacity of 226 mAh g−1 at C/20 rate with excellent cycling stability stemming from the redox reactions of oxygen and manganese. Our work isolates the role of P2 structural intergrowth and thereby introduces a novel strategy to enhance the reversibility and kinetics of anionic redox reactions in sodium layered cathodes without compromising capacity.

Enhancing Reversibility and Kinetics of Anionic Redox in O3-NaLi1/3Mn2/3O2 through Controlled P2 Intergrowth.

Anionic redox chemistry can surpass theoretical limits of conventional layered oxide cathodes in energy density. A recent model system of sodium-ion batteries, O3-NaLi1/3Mn2/3O2, demonstrated full anionic redox capacity but is limited in reversibility and kinetics due to irreversible structural rearrangement and oxygen loss. Solutions to these issues are missing due to the challenging synthesis. Here, we harness the unique structural richness of sodium layered oxides and realize a controlled ratio of P2 structural intergrowth in this model compound with the overall composition maintained. The resulted O3 with 27 % P2 intergrowth structure delivers an excellent initial Coulombic efficiency of 87 %, comparable to the state-of-the-art Li-rich NMCs. This improvement is attributed to the effective suppression of irreversible oxygen release and structural changes, evidenced by operando Differential Electrochemical Mass Spectroscopy and X-ray Diffraction. The as-prepared intergrowth material, based on the environmentally benign Mn, exhibits a reversible capacity of 226 mAh g-1 at C/20 rate with excellent cycling stability stemming from the redox reactions of oxygen and manganese. Our work isolates the role of P2 structural intergrowth and thereby introduces a novel strategy to enhance the reversibility and kinetics of anionic redox reactions in sodium layered cathodes without compromising capacity.

Sn-doped cobalt containing perovskite as the cathode for highly active SOFCs

One potential solution to the challenges of energy storage and conversion is the utilization of solid oxide fuel cells (SOFCs), which offer a versatile pathway for the generation of renewable fuels. However, the advancement of SOFC technology faces significant obstacles, including sluggish oxygen reaction kinetics, insufficient durability, and poor round-trip efficiency, primarily due to the limitations of the air electrode. To address these challenges, we present a novel Sn doped cathode BaCo0.4Fe0.5-xSnxYb0.1O3−δ (BCFSYx), designed to enhance electrochemical performance at lower temperatures. The finding demonstrates that BaCo0.4Fe0.425Sn0.075Yb0.1O3-δ (BCFSY075) displays favorable oxygen reduction reaction (ORR) performance and achieves the best power density. Furthermore, the polarization process exhibits a reduced reliance on temperature, hence enabling the potential for consistent operation at low temperatures.

FOXM1 Upregulates O-GlcNAcylation Level Via The Hexosamine Biosynthesis Pathway to Promote Angiogenesis in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) presents significant challenges in treatment and prognosis because of its aggressive nature and high metastatic potential. This study aims to investigate the role of the hexosamine biosynthesis pathway (HBP) and its association with HCC progression and prognosis. We identified SPP1 and FOXM1 as hub genes within the HBP pathway, showing their correlation with poor prognosis and late-stage progression. In addition, the analysis uncovered the complex participation of the HBP pathway in nutrients and oxygen reactions, PI3K-AKT signaling, AMPK activation, and angiogenesis regulation. The disruption of these pathways is pivotal in influencing the growth and progression of HCC. Targeting the HBP presents a promising therapeutic approach to modulate the tumor microenvironment, thereby enhancing the efficacy of immunotherapy. In addition, FOXM1 was identified as the HBP pathway regulator, influencing cellular O-GlcNAcylation level and VEGF secretion, thereby promoting angiogenesis in HCC. Inhibition of O-GlcNAcylation significantly hindered angiogenesis, which is suggested as a potential avenue for therapeutic intervention. Our research demonstrates the practicality of using the HBP-related gene as a prognostic marker in liver cancer patients and suggests targeting FOXM1 as a novel avenue for personalized therapy.

Rapid determination of the 87Sr/86Sr ratio in water samples using ICP-MS/MS without concentration matching and matrix matching

We present a rapid method for determining the 87Sr/86Sr ratio in water samples using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) in the oxygen reaction mode, thus eliminating the need for Sr purification. With O2 as the reaction gas, Sr+ ions undergo a mass shift, measured at m/z 102 and 103. Our investigation into the interference elimination, concentration effects, and matrix effects revealed that the 87Sr/86Sr determination method is robust, yielding a value of 0.7101 ± 0.0010 (2SD) for the NIST SRM 987 standard, consistent with the reference value of 0.71034 ± 0.00026 (2SD). This accuracy was maintained even with a Rb/Sr ratio of 100. Further, this method was insensitive to the concentration ratio of Sr in the sample and standard (from 0.1 to 10) and exhibited negligible sample matrix effects, as shown by the average values for an IAPSO seawater standard, calibrated with pure Sr and matrix-matched Sr standard solutions, yielding 87Sr/86Sr ratios of 0.7091 ± 0.0006 (2SD) and 0.7092 ± 0.0008 (2SD) respectively, which were consistent with the literature values. Subsequently, real water samples were analyzed using the proposed method, yielding good results.

Development of Potential Electrocatalyst: Highly Multiporous WO3–rGO Nanocomposites for Enhancing Electrocatalytic Oxygen Evolution Reactions

AbstractThe development of sustainable energy technologies, such as fuel cells and metal–air batteries, necessitates the use of a highly efficient electrocatalyst for the oxygen evolution process. The fabrication of WO3–rGO nanocomposites results in the formation of a multiporous nanostructure. The catalytic activity of highly multiporous WO3–rGO nanocomposites containing multiporous nanostructures is shown to be significant. The catalyst has the potential to facilitate highly reactive anodic oxygen reactions, hence augmenting the synergistic impact of interfacial charge transfer and the porous structure of WO3–rGO nanocomposites. The findings of this work indicate that the use of WO3–rGO nanocomposites as electrocatalysts exhibits a considerable overpotential value of 350 mV, a Tafel slope of 67 mV dec−1, good stability, roughness factor, and turnover frequency for the process of oxygen evolution in real‐world scenarios.

Understanding the interplay between electrocatalytic C(sp3)‒C(sp3) fragmentation and oxygenation reactions

Understanding the interplay between electrocatalytic C(sp3)‒C(sp3) fragmentation and oxygenation reactions

LuxA Gene From Enhygromyxa salina Encodes a Functional Homodimeric Luciferase.

Several clades of luminescent bacteria are known currently. They all contain similar lux operons, which include the genes luxA and luxB encoding a heterodimeric luciferase. The aldehyde oxygenation reaction is presumed to be catalyzed primarily by the subunit LuxA, whereas LuxB is required for efficiency and stability of the complex. Recently, genomic analysis identified a subset of bacterial species with rearranged lux operons lacking luxB. Here, we show that the product of the luxA gene from the reduced luxACDE operon of Enhygromyxa salina is luminescent upon addition of aldehydes both in vivo in Escherichia coli and in vitro. Overall, EsLuxA is much less bright compared with luciferases from Aliivibrio fischeri (AfLuxAB) and Photorhabdus luminescens (PlLuxAB), and most active with medium-chain C4-C9 aldehydes. Crystal structure of EsLuxA determined at the resolution of 2.71 Å reveals a (β/α)8 TIM-barrel fold, characteristic for other bacterial luciferases, and the protein preferentially forms a dimer in solution. The mobile loop residues 264-293, which form a β-hairpin or a coil in Vibrio harveyi LuxA, form α-helices in EsLuxA. Phylogenetic analysis shows EsLuxA and related proteins may be bacterial protoluciferases that arose prior to duplication of the luxA gene and its speciation to luxA and luxB in the previously described luminescent bacteria. Our work paves the way for the development of new bacterial luciferases that have an advantage of being encoded by a single gene.

Magnetic Properties of Reactive Oxygen Species and their Possible Role in Cancer Therapy

Spin-depending internal magnetic interactions in oxygen are crucial for the chemistry and photobiology of this molecule. Photosynthesis, respiration, and many other life-supporting oxygen reactions are governed by enzymes that use fine magnetic forces to overcome the spin-forbidden character of all aerobic metabolism. Life on Earth occurs on the border between combustion and oxidative phosphorylation, and this balance is largely dependent on reactive oxygen species. ROS can cause apoptosis or cell necrosis, and ROS also controls homeostasis through numerous signaling functions. Until recently, biochemists had not paid attention to internal magnetic interactions that influence the chemical activity of such ROS as superoxide ion, singlet oxygen, peroxynitrite, and many others. The role of superoxide dismutase, the oldest enzyme on the Earth, which provides superoxide concentration control, stresses the importance of the O2-• species as the precursor of many other ROS. Spin-orbit coupling in O2-• and O2 species are the main internal magnetic interactions that could influence cancer growth and be connected with cancer therapy.