Although the rechargeable lithium–sulfur battery system has attracted significant attention due to its high theoretical specific energy, its implementation has been impeded by multiple challenges, ...especially the dissolution of intermediate lithium polysulfide (Li2S n ) species into the electrolyte. Introducing anchoring materials, which can induce strong binding interaction with Li2S n species, has been demonstrated as an effective way to overcome this problem and achieve long-term cycling stability and high-rate performance. The interaction between Li2S n species and anchoring materials should be studied at the atomic level in order to understand the mechanism behind the anchoring effect and to identify ideal anchoring materials to further improve the performance of Li–S batteries. Using first-principles approach with van der Waals interaction included, we systematically investigate the adsorption of Li2S n species on various two-dimensional layered materials (oxides, sulfides, and chlorides) and study the detailed interaction and electronic structure, including binding strength, configuration distortion, and charge transfer. We gain insight into how van der Waals interaction and chemical binding contribute to the adsorption of Li2S n species for anchoring materials with strong, medium, and weak interactions. We understand why the anchoring materials can avoid the detachment of Li2S as in carbon substrate, and we discover that too strong binding strength can cause decomposition of Li2S n species.
Abstract
Electrochemical reduction of CO
2
to multi-carbon fuels and chemical feedstocks is an appealing approach to mitigate excessive CO
2
emissions. However, the reported catalysts always show ...either a low Faradaic efficiency of the C
2+
product or poor long-term stability. Herein, we report a facile and scalable anodic corrosion method to synthesize oxygen-rich ultrathin CuO nanoplate arrays, which form Cu/Cu
2
O heterogeneous interfaces through self-evolution during electrocatalysis. The catalyst exhibits a high C
2
H
4
Faradaic efficiency of 84.5%, stable electrolysis for ~55 h in a flow cell using a neutral KCl electrolyte, and a full-cell ethylene energy efficiency of 27.6% at 200 mA cm
−2
in a membrane electrode assembly electrolyzer. Mechanism analyses reveal that the stable nanostructures, stable Cu/Cu
2
O interfaces, and enhanced adsorption of the *OCCOH intermediate preserve selective and prolonged C
2
H
4
production. The robust and scalable produced catalyst coupled with mild electrolytic conditions facilitates the practical application of electrochemical CO
2
reduction.
Designing highly active and bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts has attracted great interest toward metal–air batteries. Herein, an efficient ...solution to the search for MXene‐based bifunctional catalysts is proposed by introducing non‐noble metals such as Fe/Co/Ni at the surfaces. These results indicate that the ultrahigh activities in Ni1/Ni2‐ and Fe1/Ni2‐modified MXene‐based double‐atom catalysts (DACs) for bifunctional ORR/OER are better than those of well‐known unifunctional catalysts with low overpotentials, such as Pt(111) for the ORR and IrO2(110) for the OER. Strain can profoundly regulate the catalytic activities of MXene‐based DACs, providing a novel pathway for tunable catalytic behavior in flexible MXenes. An electrochemical model, based on density functional theory and theoretical polarization curves, is proposed to reveal the underlying mechanisms, in agreement with experimental results. Electronic structure analyses indicate that the excellent catalytic activities in the MXene‐based DACs are attributed to the electron‐capturing capability and synergistic interactions between Fe/Co/Ni adsorbents and MXene substrate. These findings not only reveal promising candidates for MXene‐based bifunctional ORR/OER catalysts but also provide new theoretical insights into rationally designing noble‐metal‐free bifunctional DACs.
Ni1/Ni2‐ and Fe1/Ni2‐modified MXene‐based double‐atom catalysts (DACs) show the most promising bifunctional oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) catalytic performances. The bifunctional catalytic activities of DACs improve with increasing strain. Theoretical models are presented for plotting the polarization curves of OER/ORR catalysis to demonstrate the bifunctional catalytic performance of the studied catalysts.
Gaseous nitrous acid (HONO) has the potential to greatly contribute to the atmospheric oxidation capacity. Increased attention has been paid to in-particle nitrite or nitrous acid, N(III), as one of ...the HONO sources. However, sources and formation mechanisms of N(III) remain uncertain. Here, we study a much less examined reaction of Fe(II) and nitrate as a source of N(III). The N(III) production was indirectly probed by its multiphase reaction with SO2 for sulfate production. Particles containing nitrate and Fe(III) were irradiated for generating Fe(II). Sulfate production was enhanced by the presence of UV and organic compounds likely because of the enhanced redox cycle between Fe(II) and Fe(III). Sulfate production rate increases with the concentration of iron–organic complexes in nitrate particles. Similarly, higher concentrations of iron–organic complexes yield higher nitrate decay rates. The estimated production rates of N(III) under simulated conditions in our study vary from 0.1 to 3.0 μg m–3 of air h–1. These values are comparable to HONO production rates of 0.2–1.6 ppbv h–1, which fall in the values reported in laboratory and field studies. The present study highlights a synergistic effect of the coexistence of iron–organic complexes and nitrate under irradiation as a source of N(III).
Erastin was initially discovered as a small molecule compound that selectively kills tumor cells expressing ST and RAS
V12
and was later widely investigated as an inducer of ferroptosis. Ferroptosis ...is a recently discovered form of cell death caused by peroxidation induced by the accumulation of intracellular lipid reactive oxygen species (L-ROS) in an iron-dependent manner. Erastin can mediate ferroptosis through a variety of molecules including the cystine-glutamate transport receptor (system X
C
−
), the voltage-dependent anion channel (VDAC), and p53. Erastin is able to enhance the sensitivity of chemotherapy and radiotherapy, suggesting a promising future in cancer therapy. We hope that this review will help to better understand the role of erastin in ferroptosis and lay the foundation for further research and the development of erastin-based cancer therapies in the future.
In addition to core, logging, and other previous research results, this paper determines the fault development and tectonic evolution process of the Baxian sag with the Paleogene rift stage based on ...3D seismic data. The Paleogene tectonic evolution of the sag can be divided into three episodes and six evolution stages, and three types of faults are identified: intensely active normal, active normal, and weakly active normal. One first-order sequence, three second-order sequences, and fourteen third-order sequences of the Paleogene Baxian sag were created, and fifteen sequence boundaries were recognised. According to the rifting background and sedimentary facies development characteristics of each episode, five combination types of the depositional system associations were identified, including alluvial fan-fluvial and braided-delta-lacustrine in an early rifting episode, delta-lacustrine and nearshore subaqueous fan-lacustrine in the middle rifting episode, and fluvial-flood plain in the late rifting episode. Six response models of filling and the evolution process in Paleogene Baxian sag were concluded. The multi-episodes tectonic cycles of faulted lake basins resulted in complex paleogeomorphology and variable provenance supply, forming abundant sequence structure patterns and different filling and evolution processes of faulted lake basins. The stable rifting stage is favourable to form and preserve high-quality source rock, and develop various sedimentary facies and sandbody types, which is a potential area for exploration of a lithologic stratigraphic oil and gas reservoir.
•A novel ZnO nanowires/macroporous SiO2 composite support was used to immobilize horseradish peroxidase through in-situ cross-linking method using long-spaced epoxy cross-linker.•The formed ...nanobiocatalyst can provide many block-free channels for mass transfer and allow the cross-linked HRP to take a proper orientation for exposing of active site.•The positive-charged ZnO nanowires played an important role in promoting both the immobilization of HRP and the reaction between HRP and dyes.•Immobilized HRP exhibited satisfied efficiency in the decolorization of azo dyes.•The storage stability and reusability of HRP were greatly improved through the immobilization.
A ZnO nanowires/macroporous SiO2 composite was used as support to immobilize horseradish peroxidase (HRP) by in-situ cross-linking method. Using diethylene glycol diglycidyl ether (DDE) as a long-chained cross-linker, it was adsorbed on the surface of ZnO nanowires before reaction with HRPs, the resulted composite was quite different from the traditional cross-linking enzyme aggregates (CLEAs) on both structure and catalytic performance. The immobilized HRP showed high activity in the decolorization of azo dyes. The effect of various conditions such as the loading amount of HRP, solution pH, temperature, contact time and concentration of dye were optimized on the decolorization. The decolorization percentage of Acid Blue 113 and Acid black 10 BX reached as high as 95.4% and 90.3%, respectively. The immobilized HRP gave the highest decolorization rate under dye concentration as 50mg/L and reaction time of 35min. The immobilized HRP exhibited much better resistance to temperature and pH inactivation than free HRP. The storage stability and reusability were greatly improved through the immobilization, from the decolorization of Acid blue 113 it was found that 80.4% of initial efficiency retained after incubation at 4°C for 60 days, and that 79.4% of decolorization efficiency retained after 12 cycles reuse.
Dissolved iron (Fe) and manganese (Mn) share common sources and sinks in the global ocean. However, Fe and Mn also have different redox reactivity and speciation that can cause their distributions to ...become decoupled. The Arctic Ocean provides a unique opportunity to compare Fe and Mn distributions because the wide Arctic continental shelves provide significant margin fluxes of both elements, yet in situ vertical regeneration inputs that can complicate scavenging calculations are negligible under the ice of the Arctic Ocean, making it easier to interpret the fate of lateral gradients. We present here a large-scale case study demonstrating a three-step mechanism for Fe and Mn decoupling in the upper 400 m of the Western Arctic Ocean. Both Fe and Mn are released during diagenesis in porewaters of the Chukchi Shelf, but they become immediately decoupled when Fe is much more rapidly oxidized and re-precipitated than Mn in the oxic Chukchi Shelf water column, leading to Fe hosted primarily in the particulate phase and Mn in the dissolved phase. However, as these shelf fluxes are transported toward the shelf break and subducted into the subsurface halocline water mass, the loss rates of all species change significantly, causing further Fe and Mn decoupling. In the second decoupling step in the shelf break region, the dominant shelf species are removed rapidly via particle scavenging, with smallest soluble Fe (sFe < 0.02 µm) being least subject to loss, while colloidal Fe (0.02 µm < cFe < 0.2 µm), dissolved Mn (dMn), and non-lithogenic particulate Fe (pFexs) are all lost at similarly rapid rates. In the third decoupling step, once these species are swept >1000 km offshore with the prevailing current into the low-particle waters of the open Arctic, cFe and dMn appear conserved, while pFe, dFe, and sFe are very slowly removed with variable log-scale distances of transport: pFe ≪ dFe < sFe. To assess the role of physicochemical speciation on these trends, we observed that Fe(II) was a small (∼7%) fraction of total dFe in the upper 400 m of the Arctic, even over the shelf (∼2%). Also, colloidal contribution to dFe was very low (∼20%) in the open Arctic, in contrast to dFe in the North Atlantic, which is composed much more by colloids (≥50%). Throughout the Western Arctic Ocean, Fe and Mn are thus decoupled as a result of distinct oxidation kinetics and different scavenging rates within high- and low-particle regimes. As the “scavengers of the sea”, the relative distribution of particulate Fe and Mn phases across the Arctic Ocean shelf and slope, respectively, will play an important role in determining the distribution and ultimate sediment burial site for other scavenging-prone trace elements. Additionally, we suggest that the future effects of climate change, including loss of sea ice that could impact the formation of the halocline, might change distributions of Fe and Mn species in the future Western Arctic.
The Arctic Ocean is a region of great scientific interest, particularly considering the rapid rate at which temperature and sea-ice coverage have changed over the past decade and the projections ...under various climate scenarios. In this context, the marine nutrient-like element cadmium (Cd) and its stable isotope ratios (δ114Cd) provide valuable insights into the modern physical and biological processes in the Arctic. However, few data on the Arctic are available because of the difficulty of accessing this region. Here, we present measurements of dissolved Cd and δ114Cd, and leachable particulate Cd, in the Western Arctic Ocean during the U.S. GEOTRACES GN01 cruise. Broadly, the Arctic Ocean reflects mixing between Pacific and Atlantic end-members. Waters from the Bering Sea just outside the Arctic in the North Pacific have the lightest deep water δ114Cd values yet reported and some of the highest Cd concentrations (∼+0.17‰; ∼1.00 nmol kg−1), reflecting the buildup of isotopically light Cd along the ocean conveyor belt. Conversely, waters in the deep Arctic have the lowest Cd concentrations and highest δ114Cd of any deep ocean (∼0.2 nmol kg−1; ∼+0.5‰) reflecting input of waters from the North Atlantic. More subtle features of mixing can also be observed, for example within the Arctic near the Bering and Chukchi Shelves, where a tongue of high-Cd, low δ114Cd Pacific water lies below the surface. In the surface water, we observe low Cd and higher δ114Cd, reflecting dilution by low-Cd sea ice melt as well as biological uptake in the surface Arctic and over the Bering shelf as waters flow in from the Pacific. Surface water δ114Cd decreases towards the North Pole under the permanent ice zone due to mixing with North Atlantic waters. Other processes of note inferred from our data include Cd input from Bering and Chukchi shelf sediments and an unexplained mechanism causing high δ114Cd found in intermediate waters over the Chukchi Abyssal Plain. Finally, we observe waters in the deep Arctic with lower Cd/PO4 than observed anywhere else in the global ocean, perhaps reflecting differences in North Atlantic circulation and nutrient cycling during the Little Ice Age when the waters were formed, an input of dissolved PO4 originating from PO4 scavenged onto sedimented Fe oxyhydroxide particles, or an input of dissolved PO4 from sedimentary weathering of glacial minerals. Our data provide a means for better understanding biogeochemical cycling in the modern Arctic as well as a baseline for comparison with future biogeochemical change.
Heterogeneous oxidation of SO2 is one of the promising mechanisms to account for high loading of sulfate during severe haze periods in China. Our earlier work reported on the SO2 oxidation by OH and ...NO2 produced during 250 nm nitrate photolysis (Environ. Sci. Technol. Lett. 2019, 6, 86–91). Here, we extend that work to examine sulfate production during nitrate photolysis at 300 nm irradiation, which can additionally generate NO2 – or HNO2, N(III). Flow cell/in situ Raman experiments showed that the reactive uptake coefficient of SO2, γSO2 , can be expressed as γSO2 = 1.64 × p NO3–, where p NO3− is the nitrate photolysis rate in the range of (1.0–8.0) × 10–5 M s–1. Our kinetic model with the p NO3− predicts that N(III) is the main contributor to the SO2 oxidation, followed by NO2 contribution. Furthermore, the addition of OH scavengers (e.g., glyoxal or oxalic acid) does not suppress the sulfate production because of the reduced N(III)-consuming reactions and the high particle pH sustained by their presence. Our calculations illustrate that under characteristic haze conditions, the nitrate photolysis mechanism can produce sulfate at ∼1 μg m–3 h–1 at pH 4–6 and p NO3– = 10–5 M s–1. The present study highlights the importance of in-particle nitrate photolysis in heterogeneous oxidation of SO2 by reactive nitrogen (NO2 –/HNO2 and NO2) under atmospherically relevant actinic irradiation. However, the nitrate photolysis rate constant needs to be better constrained for ambient aerosols.
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