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Covalent Organic Frameworks as a Decorating Platform for Utilization and Affinity Enhancement of Chelating Sites for Radionuclide Sequestration
The potential consequences of nuclear events and the complexity of nuclear waste management motivate the development of selective solid-phase sorbents to provide enhanced protection. Herein, we show that two dimensional covalent organic frameworks (COFs) with unique structures possess all the traits to be well-suited as a platform for the deployment of highly efficient sorbents such that they exhibit remarkable performance, as demonstrated by uranium capture. The chelating groups laced on the open one dimensional channels exhibit exceptional accessibility, allowing significantly higher utilization efficiency. In addition, the two dimensional extended polygons packed closely in an eclipsed fashion bring chelating groups in adjacent layers parallel to each other, which may facilitate their cooperation, thereby leading to high affinity towards specific ions. As a result, the amidoxime functionalized COFs far outperform their corresponding amorphous analogues in terms of adsorption capacities, kinetics, and affinities
Synergistic Cr[subscript 2]O[subscript 3]@Ag Heterostructure Enhanced Electrocatalytic CO[subscript
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Enhancing and Extinguishing the Different Emission Features of 2D (EA(1-)(x)FA(x))(4)Pb3Br10 Perovskite Films
2D hybrid perovskites are attractive for optoelectronic devices. In thin films, the color of optical emission and the texture of crystalline domains are often difficult to control. Here, a method for extinguishing or enhancing different emission features is demonstrated for the family of 2D Ruddlesden-Popper perovskites (EA(1-)(x)FA(x))(4)Pb3Br10 (EA = ethylammonium, FA = formamidinium). When grown from aqueous hydrobromic acid, crystals of (EA(1-)(x)FA(x))(4)Pb3Br10 retain all the emission features of their parent compound, (EA)(4)Pb3Br10. Surprisingly, when grown from dimethylformamide (DMF), an emission feature, likely self-trapped exciton (STE), near 2.7 eV is missing. Extinction of this feature is correlated with DMF being incorporated between the 2D Pb-Br sheets, forming (EA(1-)(x)FA(x))(4)Pb3Br10 center dot(DMF)(y). Without FA, films grown from DMF form (EA)(4)Pb3Br10, retain little solvent, and have strong emission near 2.7 eV. Slowing the kinetics of film growth strengthens a different emission feature, likely a different type of STE, which is much broader and present in all compositions. Films of (EA(1-)(x)FA(x))(4)Pb3Br10 center dot(DMF)(y) have large, micron-sized domains and homogeneous orientation of the semiconducting sheets, resulting in low electronic disorder near the absorption edge. The ability to selectively strengthen or extinguish different emission features in films of (EA(1-)(x)FA(x))(4)Pb3Br10 center dot(DMF)(y) reveals a pathway to tune the emission color in these compounds.
Manipulating Copper Dispersion on Ceria for Enhanced Catalysis: A Nanocrystal-Based Atom-Trapping St
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Dendrite-Free and Performance-Enhanced Lithium Metal Batteries through Optimizing Solvent Compositions and Adding Combinational Additives
The instability of lithium (Li) metal anode due to the dendritic growth and low Coulombic efficiency hinders the practical application of the well-regarded high-energy-density Li metal batteries. Here we report the systematic studies of improving the stability of Li metal anode and the electrochemical performances of the related Li metal batteries through the addition of combinational additives and the optimization of solvent compositions in dual-salt/carbonate electrolytes. A dendrite-free and high Coulombic efficiency of 98.1% for Li metal anode is achieved. The well protection of the Li metal anode and the excellent cyclability and rate capability of the 4-V Li metal batteries have been obtained. This is attributed to the formation of a robust, denser, more polymeric and higher ionic conductive surface film on the Li metal anode via the electrochemical reductive decompositions of the electrolyte components and the ring-opening polymerization of additives and cyclic carbonate solvents. The key findings of this work emphasize that the optimization of solvent compositions and the manipulation of the additives are facile and effective to enhance the Li metal battery performances.
Enhanced Stability of Li Metal Anodes by Synergetic Control of Nucleation and the Solid Electrolyte Interphase
Use of a protective coating on a lithium (Li) metal anode (LMA) is an effective approach to enhance its coulombic efficiency and cycling stability. Here we report a facile approach to produce uniform silver (Ag) nanoparticle-decorated LMAs for high-performance Li metal batteries (LMBs). This effective treatment can lead to well controlled nucleation and the formation of a stable solid electrolyte interphase (SEI). Ag nanoparticles embedded in the surface of Li anodes induced uniform Li plating/stripping morphologies with reduced overpotential. More importantly, cross-linked lithium fluoride (LiF) networks formed during Ag+ reduction enabled a highly stable SEI layer. Based on the Ag-LiF decorated anodes, LMBs with LiNi1/3Mn1/3Co1/3O2 cathode (~1.8 mAh cm-2) can retain >80% capacity over 500 cycles. The similar results were also obtained when the same approach was applied to the design of stable sodium (Na) anodes. These results indicate that synergetic control of the nucleation and SEI is an efficient approach to stabilize rechargeable metal batteries.
Enhancing hydrogen‐dependent growth of and carbon dioxide fixation by Clostridium ljungdahlii through nitrate supplementation
Abstract Synthesis gas (syngas) fermentation via the Wood–Ljungdahl pathway is receiving growing attention as a possible platform for the fixation of and renewable production of fuels and chemicals. However, the pathway operates near the thermodynamic limit of life, resulting in minimal adenosine triphosphate (ATP) production and long doubling times. This calls into question the feasibility of producing high‐energy compounds at industrially relevant levels. In this study, we investigated the possibility of co‐utilizing nitrate as an inexpensive additional electron acceptor to enhance ATP production during ‐dependent growth of Clostridium ljungdahlii , Moorella thermoacetica , and Acetobacterium woodii . In contrast to other acetogens tested, growth rate and final biomass titer were improved for C. ljungdahlii growing on a mixture of and when supplemented with nitrate. Transcriptomic analysis, labeling, and an electron balance were used to understand how electron flux was partitioned between and nitrate. We further show that, with nitrate supplementation, the ATP/adenosine diphosphate (ADP) ratio and acetyl‐CoA pools were increased by fivefold and threefold, respectively, suggesting that this strategy could be useful for the production of ATP‐intensive heterologous products from acetyl‐CoA. Finally, we propose a pathway for enhanced ATP production from nitrate and use this as a basis to calculate theoretical yields for a variety of products. This study demonstrates a viable strategy for the decoupling of ATP production from carbon dioxide fixation, which will serve to significantly improve the fixation rate and the production metrics of other chemicals from and in this host.
Selective Host-Guest Interaction between Metal Ions and Metal-Organic Frameworks Using Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy
The host–guest interaction between metal ions (Pt²⁺ and Cu²⁺) and a zirconium metal–organic framework (UiO-66-NH₂) was explored using dynamic nuclear polarization-enhanced ¹⁵N{¹H} CPMAS NMR spectroscopy supported by X-ray absorption spectroscopy and density functional calculations. The combined experimental results conclude that each Pt²⁺ coordinates with two NH₂ groups from the MOF and two Cl⁻ from the metal precursor, whereas Cu²⁺ do not form chemical bonds with the NH₂ groups of the MOF framework. Density functional calculations reveal that Pt²⁺ prefers a square-planar structure with the four ligands and resides in the octahedral cage of the MOF in either cis or trans configurations.
Giant Pressure-Induced Enhancement of Seebeck Coefficient and Thermoelectric Efficiency in SnTe
The thermoelectric properties of polycrystalline SnTe have been measured up to 4.5 GPa at 330 K. SnTe shows an enormous enhancement in Seebeck coefficient, greater than 200 % after 3 GPa, which correlates to a known pressure-induced structural phase transition that is observed through simultaneous in situ X-ray diffraction measurement. Electrical resistance and relative changes to the thermal conductivity were also measured, enabling the determination of relative changes in the dimensionless figure of merit (ZT), which increases dramatically after 3 GPa, reaching 350 % of the lowest pressure ZT value. The results demonstrate a fundamental relationship between structure and thermoelectric behaviours and suggest that pressure is an effective tool to control them.
Highly Enhanced Curie Temperature in Ga-Implanted Fe3GeTe2 van der Waals Material
Among many efforts in the research of van der Waals (vdW) magnetic materials, increasing the Curie temperature above room temperature has been at the center of research in developing spintronics technology using vdW materials. Here an effective and reliable method of increasing the Curie temperature of ferromagnetic Fe3GeTe2 vdW materials by Ga implantation is reported. It is found that implanting Ga into Fe3GeTe2 by the amount of 10-3 Ga Å-3 could greatly enhance the Fe3GeTe2 Curie temperature by almost 100%. Spatially resolved microdiffraction and element-resolved X-ray absorption spectroscopy show little changes in the Fe3GeTe2 crystal structure and Fe valence state. In addition, the Ga implantation changes the Fe3GeTe2 magnetization from out-of-plane direction at low temperature to in-plane direction at high temperature. The result opens a new opportunity for tailoring the magnetic properties of vdW materials beyond room temperature.
A New Class of Proton Conductors with Dramatically Enhanced Stability and High Conductivity for Reversible Solid Oxide Cells
Reversible solid oxide cells based on proton conductors (P-ReSOCs) have potential to be the most efficient and low-cost option for large-scale energy storage and power generation, holding promise as an enabler for the implementation of intermittent renewable energy technologies and the widespread utilization of hydrogen. Here, the rational design of a new class of hexavalent Mo/W-doped proton-conducting electrolytes with excellent durability while maintaining high conductivity is reported. Specifically, BaMo(W) 0.03 Ce 0.71 Yb 0.26 O 3-δ exhibits dramatically enhanced chemical stability against high concentrations of steam and carbon dioxide than the state-of-the-art electrolyte materials while retaining similar ionic conductivity. In addition, P-ReSOCs based on BaW 0.03 Ce 0.71 Yb 0.26 O 3-δ demonstrate high peak power densities of 1.54, 1.03, 0.72, and 0.48 W cm –2 at 650, 600, 550, and 500 °C, respectively, in the fuel cell mode. During steam electrolysis, a high current density of 2.28 A cm –2 is achieved at a cell voltage of 1.3 V at 600 °C, and the electrolysis cell can operate stably with no noticeable degradation when exposed to high humidity of 30% H 2 O at –0.5 A cm –2 and 600 °C for over 300 h. Altogether, this work demonstrates the promise of donor doping for obtaining proton conductors with both high conductivity and chemical stability for P-ReSOCs.
Assessing liver function: diagnostic efficacy of parenchymal enhancement and liver volume ratio of Gd-EOB-DTPA-enhanced MRI study during interstitial and hepatobiliary phase
Aim: To assess the efficacy of signal intensity in interstitial and hepatobiliary phase normalized for liver volume, on gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) study, for the evaluation of liver function through the comparison with Child–Pugh (CP), model for end-stage liver disease (MELD), and biochemical tests. Methods: All dynamic Gd-EOB-DTPA MRI studies performed in patients with suspected liver lesions were retrospectively reviewed. The rate of liver-to-muscle ratio on T1 sequence 70 s (interstitial phase) and 20 min (hepatobiliary phase) after injection of Gd-EOB-DTPA was calculated for each MRI study and then normalized for liver volume (irINTnorm and irHEPnorm). Pearson correlation coefficient was computed to assess the correlation among these values and CP and MELD scores, and biochemical tests. Results: A total of 303 MRI studies, performed on 221 patients, were included. Mean age was 63.8 years ± 12.9 with a majority of male patients (186; 61.4%). A total of 186 out of 303 (61.4%) were cirrhotic patients. The irHEPnorm was significantly lower in cirrhotic than non-cirrhotic patients (0.0004 ± 0.0002 to 0.0005 ± 0.0003, p = 0.010). This value had a moderate, significant correlation with Child–Pugh and MELD scores (R = − 0.292, p < 0.0001 and R = − 0.192, p = 0.010, respectively). In particular, irHEPnorm progressively decreased from Child–Pugh A to C (0.0004–0.0002, p < 0.0001) and from MELD ≤ 10 to 19–24 (0.0004–0.0003, p = 0.018). Among biochemical parameters, total bilirubin, GOT, and albumin had the strongest correlation with irHEPnorm (R = − 0.258, − 0.291, and 0.262, p < 0.0001, respectively). No correlations were found between irINTnorm and CP and MELD scores. Conclusion: irHEPnorm value derived from Gd-EOB-DTPA-enhanced MRI is a reliable, non-invasive, useful tool to quantify liver function and to assess the degree of cirrhosis, offering a strict relationship with clinical scores and biochemical parameters. This could help surgeons in clinical decision-making, allowing them to choose the more suitable surgical approach for cirrhotic patients.
Enhancing Building Resilience: Maintaining Energy Efficiency and Thermal Comfort During Power Outages in Cold Climates
The increasing frequency and intensity of extreme weather events, such as heatwaves and cold snaps, present significant challenges to building energy performance and occupant comfort. Highly correlated with climate events are widespread long duration power interruptions that may affect thousands of buildings and millions of customers. This study evaluates the impact of building energy performance and occupant thermal comfort in medium-sized office buildings in a cold climate region. Using energy models representing pre-1980 and 2019 vintages, simulations were conducted to assess energy performance under typical weather conditions and occupant thermal comfort during power interrupted extreme cold snap and heatwave climate events under both current 2020s and future 2050s weather conditions. The results show a projected 33% increase in cooling energy demand and a 19% reduction in heating energy by 2050. Findings reveal that older buildings are more susceptible to cold discomfort during cold snaps, while modern airtight buildings are more vulnerable to overheating during heatwaves. Various passive energy efficiency measures, such as improved infiltration control, thermal windows, solar-controlled windows, and cool envelopes, were evaluated for their ability to mitigate thermal discomforts. Solar controlled windows and weatherstripping contribute to reducing cold thermal discomfort by 21% during a power-interrupted cold snap. Solar-controlled windows were found to reduce hot thermal discomfort by 34% during a future power-interrupted heatwave. The study highlights the importance of targeted retrofitting strategies to enhance thermal resilience, especially during power outages, to ensure occupant safety and comfort during extreme climate events.
Transgenic Ferritin Overproduction Enhances Thermochemical Pretreatments in Arabidopsis
Abstract not provided
Enhanced chemical activity and wettability at adjacent Brønsted acid sites in HZSM-5
Not provided.