Oxide Precursor Research Articles

Amorphous metal-organic frameworks-derived In2O3 microstructures with abundant oxygen vacancies for superior chlorine gas sensing performance

Metal-organic frameworks (MOFs) are characterized by their porous structures, which provide an exceptionally large specific surface area and a precisely controlled composition. Amorphous MOFs (aMOFs) integrate the diverse properties of MOFs with those of amorphous materials, such as hierarchical morphology and abundant deficiencies. Therefore, aMOFs serve as promising precursors for metal oxides with porous structures and rich vacancies. NH2-MIL-68 (In) is a novel indium-MOF material with promising features. In this research, the amorphous NH2-MIL-68 (In) (aNH2-MIL-68 (In)) was chosen as the template. Indium oxide rough straight rods (a-In2O3 RSRs) with extensive oxygen vacancies were prepared, where a- indicates that the precursor is amorphous. As a result, the a-In2O3 RSRs sensor demonstrated an outstanding gas sensing response towards 2 ppm chlorine (Cl2) at a low temperature of 160℃. This study is the first to report that the aMOFs can be employed as gas sensing materials with superior Cl2 detection capabilities, offering a promising method for real-time gas monitoring.

Enhanced lithium-ion storage through anchoring nanocrystalline MoO2/C microspheres in rGO nanosheets: Boosting pseudocapacitance and facilitating rapid conversion

Both crystalline and amorphous MoO2 exhibit distinct advantages for lithium-ion battery applications, with the former favoring lithium-ion intercalation and the latter undergoing complete lithiation via a conversion reaction. However, their sluggish lithium-ion insertion rates and inadequate charge transfer kinetics hinder their full potential. To address these challenges, we have developed a controllable approach that integrates liquid-phase dispersion of the HxMoO3/C and graphene oxides (GO) precursors followed by freeze-drying and low-temperature calcinations, aiming to merit the ionic conductivity of MoO2/C nanocrystallite and the electronic conductivity of reduce graphene oxides (rGO), respectively. This facile method yields bubble-sheet-like MoO2/C@rGO composites, where the quantitatively strategic incorporation of rGO can effectively mitigate recrystallization and surface oxidation of MoO2 nanocrystals. Furthermore, the approximately 70 % volume shrinkage of HxMoO3/C precursors into MoO2/C can create a flexible void space between the microspheres and the rGO coating for better accommodating volume variations during lithiation. Electrochemical measurements show that MoO2/C@rGO delivers high initial coulombic efficiency (ICE, e.g., up to 71.3 % at 100 mA g⁻¹), impressive rate performance (e.g., achieving 60 mA h g⁻¹ at 1 A g⁻¹, and 34.1 % retention from 0.1 to 2 A g⁻¹) and excellent cyclability (e.g., retaining 98.9 % of its capacity after 200 cycles) when employed as an intercalation-type anode material above 1.00 V (vs. Li/Li⁺). Remarkably, electrochemical analysis indicates that the capacitive contribution is dominant during high-rate applications (e.g., up to 73.06 % ratio at a scan rate of 0.50 mV s⁻¹), exhibiting a pseudocapacitive behavior. Additionally, MoO2/C@rGO exhibits enhanced ICE (e.g., up to 76.9 % at 100 mA g⁻¹), accelerated activation (e.g., achieving peak performance within 10 cycles at 100 mA g⁻¹), superior rate performance (e.g., achieving 446 mA h g⁻¹ at 2 A g⁻¹), and remarkable cyclability (e.g., maintaining 510 mA h g⁻¹ with 88.9 % capacity retention over 600 cycles at 1 A g⁻¹) when applied as a conversion-type anode material at between 1.00 and 3.00 V (vs. Li/Li⁺). To elucidate the mechanisms underlying the high-rate performance and the increased capacity, ex-situ XRD, ex-situ SEM, ex-situ TEM, and electrochemical analysis were carried out. No evident phase transition or material pulverization can be observed upon cycling above 1.00 V; therefore, the structural evolution is entirely single-phase or solid-solution, which accompanies with pseudocapacitive characteristic. However, the diffraction peaks downshift, the eminent of LixMoO2+δ, the pulverization, and the gradual amorphization of MoO2 can be observed upon cycling, indicating an sequential intercalation-to-conversion activation from a crystalline state to an amorphous state.

Microstructure and magnetic properties of Fe-Al2O3 nanocomposites prepared by a versatile facile combustion-based route

Fe-Al2O3 nanocomposites with Al2O3 nanoparticles uniformly dispersed have been successfully prepared via a versatile facile and scalable combustion-based route with two steps. Firstly, the homogenous mixed oxide precursor composed with α-Fe2O3, γ-Fe2O3 and Al2O3 was prepared by solution combustion synthesis. Subsequently, Fe-Al2O3 nanocomposites with Al2O3 nanoparticles evenly dispersed were prepared by hydrogen reduction of the mixed oxide precursor. The effects of the various reduction temperatures on the phase composition, morphology, grain size and magnetic properties of the Fe-Al2O3 nanocomposites were investigated in details. The results show that the Fe-Al2O3 nanocomposites prepared at as low as 400 °C present a connected network structure with an average grain size of about 17 nm, which have a saturation magnetization of 125.3 emu/g, and a coercivity of 721.2 Oe. With the increase of reduction temperature, the average grain size, and saturation magnetization of the Fe-Al2O3 nanocomposites increase gradually, while the coercivity decrease. When the reduction temperature is increased to 500 °C and 600 °C, the grain size increases to about 27 nm and 37 nm, the saturation magnetization increases to 153.6 emu/g and 177.1 emu/g, and the coercivity decreases to 634.6 Oe and 467.8 Oe, respectively.

A novel and facile strategy for the preparation of highly reactive NiMo/γ-Al2O3 hydrodesulfurization catalyst

Traditionally, the commercial Ni(Co)Mo(W)/Al2O3 hydrodesulfurization (HDS) catalysts were prepared with corresponding oxidation precursors and then sulfured with CS2 or H2S, which is complex and time-consuming. Herein, a novel “O-S exchanging” strategy was proposed to directly synthesize a series of highly efficient Ni-MoS2/Al2O3 HDS catalysts with various Mo loading using MoS42− solution as a novel active precursor, and their catalytic performances were evaluated for 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS. The experimental results showed that under the same reaction conditions, the catalyst with 15 wt% MoO3 (S-CAT-15) exhibited a HDS rate up to 99.8 % for 240 h, which was not only nearly two times higher than that of O-CAT-15 counterpart prepared by the conventional oxidation precursor with the same metal loading, but also even 1.6 times higher than that of O-CAT-20 with a higher metal loading, demonstrating its excellent HDS performance and outstanding stability. The deep characterization analyses unveiled that the superior HDS performance of S-CAT-15 was attributed to this novel strategy, which not only notably improved the sulfidation of Mo species, but also considerably promoted the decoration of Ni atoms onto the edges of MoS2 slabs forming more reactive Type-II Ni-Mo-S sites, thereby remarkably enhancing the HDS performances of S-CAT catalysts. This work may offer a novel protocol to guide the fabrication of more efficient industrial hydrogenation catalysts in the future.

Self-supported bifunctional porous Ni–Fe-based electrode via one-step reduction method for efficient water splitting

Efficient, inexpensive, and robust bifunctional electrodes are crucial for water splitting. Herein, the three-dimensional hierarchical porous nickel-iron (Ni–Fe)- based monolith is directly fabricated through a one-step reduction approach of their oxide precursors under a hydrogen atmosphere. The Ni–Fe alloy as the active material of water splitting is simultaneously formed during the reduction process and water is the only by-product, which is facile and environmentally friendly. The effects of the reduction temperatures and the Fe contents on the microstructures and composition of the obtained Ni–Fe samples are systematically investigated. The optimized Ni–Fe-based monolith is used as a self-supporting electrode for oxygen evolution reaction, its electro-oxidized derivatives show a low overpotential of 217 mV at 10 mA cm−2 and an ultralow Tafel slope of 31 mV dec−1 in 1 M KOH. Furthermore, the electrolyzer consisting of the bifunctional electrode demonstrates outstanding performance of 1.49 V at 10 mA cm−2 and exceptional long-term stability over 1000 h at 50 mA cm−2, surpassing the majority of alkaline electrolyzers utilizing Ni–Fe-based electrodes.

Preparation of GO/BiOI composites and their degradation performance in Congo red solution

GO/BiOI photocatalytic nanocomposites were synthesized through a hydrolysis precipitation method, utilizing (Bi(NO3)3·5H2O) as the bismuth precursor and graphene oxide (GO) as the substrate. The removal effect of the material on Congo red (CR) in water was investigated by taking CR as the target pollutant. The composite’s structure and characteristics were examined through various analytical methods, including XRD, BET, FT-IR, FE-SEM, TEM, and UV–Vis techniques. The findings indicate that the integration of GO with BiOI preserves the layered crystalline structure of BiOI and mitigates particle aggregation. The specific surface area of the GO/BiOI composites increased significantly, from 21.98 m2/g for BiOI to 80.2586 m2/g, and the bandgap was decreased from 1.94 eV to 1.82 eV. The GO/BiOI photocatalytic degradation conformed to the first-order kinetic model. When the initial concentration of CR was 20 mg/L, the rate constant was the largest, and the correlation coefficient was 0.9988. At a dosage of 200 mg/L for GO/BiOI, with an initial concentration of 20 mg/L for CR solution, a pH level of 5, and under LED illumination at 12 W, the composite material achieved a CR removal efficiency of 96.09 %. After being reused five times, the removal rate could still reach more than 90 %.

Constructing a novel Bi2MoO6/TiO2/Ti3C2 composite with efficient carrier separation for excellent photocatalytic purification of TC

Photocatalytic removal of tetracycline (TC) from wastewater is an advantageous method with green and efficient potentials, while the low light utilization and severe charge carrier recombination of conventional photocatalysts limit their practical application. The TiO2/Ti3C2 derived from in-situ partly oxidation of Ti3C2 MXene precursors on which Bi2MoO6 (BMO) was tightly loaded was synthesized via a facile hydrothermal synthesis route. The introducing TiO2/Ti3C2 accelerated the transfer of electrons, improving the efficiency of electron-hole separation, thus strengthened the photocatalytic performance. Under optimum conditions, the BMO/TiO2/Ti3C2 composite significantly removed 87.54 % TC from wastewater within 150 min, which was higher than the original counterparts and remained almost unchanged after four cycles. The active species trapping experiments and ESR analysis displayed that •O2- played a dominant role in TC degradation. The possible degradation pathways were also deduced through liquid chromatography-mass spectrometry (LC-MS) analysis experiments, demonstrating that the terminal products of degradation were mainly CO2 and H2O, confirming the potential of BMO/TiO2/Ti3C2 photocatalyst for the environmentally friendly treatment of antibiotic pollutants in wastewater.

Oxidative hydrothermal carbonization to fabricate versatile magnetic biochar for Fenton-like degradation of phenolic compounds

Magnetic biochar (MBC) has drawn great attention as a versatile catalyst for advanced oxidation elimination of pollutants from aqueous solution with synergy of iron species and carbon matrix. Herein, an MBC was manufactured by oxidative hydrothermal carbonization employing potassium ferrate as precursor and internal oxidant for Fenton-like degradation of phenols in aqueous solution. This unique oxidative hydrothermal carbonization allowed multiple iron species to be introduced with persistent free radicals (PFRs), providing diverse catalysis sites for activating H2O2 into reactive oxygen species (ROSs) for efficient degradation of phenols. Moreover, graphite structure was generated with abundant oxygen functional groups, benefiting to accelerating Fe3+/Fe2+ cycle by electron shuttle and transfer. The catalysis degradation efficiency was up to 99.74 % with 44.4 % of total organic carbon (TOC) removal rate for 75 mg L−1 of phenol using 0.2 g L−1 MBC dosage. Satisfactory recyclability was achieved for the MBC as the catalysis degradation efficiency slightly decreased from 99.74 % to 87.95 % after five times recycling. Moreover, the MBC catalysis system exhibited extensive applicability in real water matrices and for degradation of different phenols with high efficiency. Serving as a demonstration of oxidized magnetic biochar for efficient Fenton-like degradation of phenols, this work highlighted the great potential of oxidative hydrothermal carbonization in preparation of high performance magnetic biochar.

A General Approach for Metal Nanoparticle Encapsulation Within Porous Oxides.

Encapsulation of metal nanoparticles within oxide materials has been shown as an effective strategy to improve activity, selectivity, and stability in several catalytic applications. Several approaches have been proposed to encapsulate nanoparticles, such as forming core-shell structures, growing ordered structures (zeolites or metal-organic frameworks) on nanoparticles, or directly depositing support materials on nanoparticles. Here, a general nanocasting method is demonstrated that can produce diverse encapsulated metal@oxide structures with different compositions (Pt, Pd, Rh) and multiple types of oxides (Al2O3, Al2O3-CeO2, ZrO2, ZnZrOx, In2O3, Mn2O3, TiO2) while controlling the size and dispersion of nanoparticles and the porous structure of the oxide. Metal@polymer structures are first prepared, and then the oxide precursor is infiltrated into such structures and the resulting material is calcined to form the metal@oxide structures. Most Pt@oxides catalysts show similar catalytic activity, demonstrating the availability of surface Pt sites in the encapsulated structures. However, the Pt@Mn2O3 sample showed much higher CO oxidation activity, while also being stable under aging conditions. This work demonstrated a robust nanocasting method to synthesize metal@oxide structures, which can be utilized in catalysis to finely tune metal-oxide interfaces.

Structures and NMR Solution Dynamics of Diorganotin Complexes with Bulky Quadridentate Salen‐ and Salphen‐Type Schiff Bases (N2O2) Incorporating Diazenylpyridyl Side Arms

AbstractA series of six complexes [n‐Bu2Sn(L1)]⋅S (S=Benzene/toluene, mixed/partial) (1), [Ph2Sn(L1)]n⋅S (S=Benzene) (2), [Bz2Sn(L1)] (3), [n‐Bu2Sn(L2)]n (4), [Ph2Sn(L2)] (5) and [Bz2Sn(L2)] (6) were synthesized using diorganotin(IV) oxide precursors and two new bis‐Schiff bases containing N2O2 donor atoms. The Schiff bases, H2L1 and H2L2, were prepared by reacting ethane‐1,2‐diamine or benzene‐1,2‐diamine with 2‐hydroxy‐5‐(pyridin‐3‐yldiazenyl)benzaldehyde in absolute ethanol. Compounds 1–6 were characterized by IR and NMR spectroscopies, as well as by solid‐state single‐crystal X‐ray diffraction (except for 3 and 6). In all the complexes the bis‐Schiff bases occupy the equatorial positions and the R groups are in axial sites. However, while 1 and 5 are discrete molecules where the tin atoms adopt distorted octahedral geometries, 2 and 4 are monoperiodic polymers with the metal cations in pentagonal bipyramidal environments. Although solid state crystallographic results revealed asymmetrical molecular configurations, solution NMR studies proved symmetric arrangements for all the compounds. Tin NMR spectroscopy confirmed that all complexes are six‐coordinate in solution, despite variations in solid‐state coordination. Further analysis using Hirshfeld surface and fingerprint plots provided insights into intermolecular interactions in compounds 1, 2, 4, and 5. This comprehensive study underscores the structural diversity and solution‐state dynamics of organotin(IV) complexes synthesized using novel Schiff bases.

Study on Oxygen Plasma-Based Copper Etching Process

A plasma-based, room-temperature copper etch process using the chlorine- or bromine-containing feed gas was reported. This simple process could potentially replace the chemical mechanical polishing method in preparing copper interconnects. However, the chlorine- and bromine-containing gases are corrosive and must be handled with expensive equipment following stringent safety procedures. In this paper, the oxygen plasma-based copper etch process is presented. The copper film was converted into a porous and polycrystalline copper oxide film which was subsequently dissolved in a dilute hydrochloric acid solution. The copper film was expanded when converted into an oxide film. The oxidation precursors, i.e., oxygen radicals and ions, were generated in the plasma phase and then transported through the oxide layer to the underneath copper film where the oxidation reaction proceeded. The oxide growth rate is affected by plasma parameters, such as pressure and power, and the kinetics of the oxidation reaction. This new oxygen plasma-based process is a simple solution for preparing copper interconnects for nano and microelectronic products.

Global Temperature Dependency of Biogenic HCHO Columns Observed From Space: Interpretation of TROPOMI Results Using GEOS‐Chem Model

AbstractTemperature is the principal driver of global atmospheric formaldehyde (HCHO) and its primary oxidation precursor biogenic volatile organic compounds (BVOCs). We revisit such a temperature (T‐) dependency globally, leveraging TROPOMI HCHO column data. We find substantial variations in the T‐dependency of biogenic HCHO across plant functional types (PFTs), with the highest over Broadleaf Evergreen Tropical Trees (doubling every 6.0 K ± 4.1 K) and lowest over Arctic C3 Grass (doubling every 30.8 K ± 9.6 K). The GEOS‐Chem model interprets HCHO columns' T‐dependency at the PFT level (r = 0.87), with a 16% discrepancy on average. The discrepancy can be explained by BVOC emissions T‐dependency for Broadleaf Evergreen Tropical Trees and Warm C4 Grass and can be attributed to the insensitivity of HCHO columns to BVOC emissions for other PFTs. Our findings underscore a potentially magnified variation of BVOC emissions by GEOS‐Chem and MEGAN therein, particularly in regions experiencing greater temperature variations.

Modeling impacts of indoor environmental variables on secondary organic aerosol formation

There are numerous air pollutants indoors including chemicals emitted from building environments as well as outdoor-origin species due to human activities. Despite the significance of indoor air quality, the atmospheric process indoors is not well studied. In this study, the secondary organic aerosol (SOA) formation from the oxidation of α-pinene blended with toluene was simulated under varying indoor environments (lamps, NO2, ozone, and inorganic seed) using the UNIfied Partitioning Aerosol Reaction (UNIPAR) model. Explicitly predicted lumping species produced during the atmospheric oxidation of precursors are used in the model and they process multiphase partitioning and aerosol phase reactions. The performance of the model was demonstrated using indoor chamber experiments in both dark conditions (ozonolysis) and light conditions with commercialized fluorescent or LED lamps. α-Pinene SOA was dominated by ozonolysis even in the presence of indoor light. Toluene, which is known to be photochemically processed, was oxidized in the dark condition with OH radicals that were derived from ozonolysis products of α-pinene. At given dark simulation conditions (10 ppb α-pinene, 30 ppb ozone, and 50 ppb of toluene), toluene contributed 15 % of SOA mass. α-Pinene SOA was insensitive to hygroscopicity of inorganic seed, but toluene blended with α-pinene increased the sensitivity to seed conditions due to the formation of oligomeric matter via aqueous reactions of reactive toluene products. In the presence of NO2. α-pinene SOA formation significantly increased with increasing NO2 owing to the reaction of α-pinene with nitrate radicals to form low volatile products. This study concludes that ozone and NO2, intruded from outdoors to indoors, effectively oxidize terpenes and furthermore aromatic hydrocarbons with OH radicals originating from ozonolysis of terpenes. The reaction paths with ozone and nitrate radicals are more effective at forming SOA than that with OH radical under the indoor light condition with commercialized lamps.

Structure and Magnetic Properties of the n = 3 Ruddlesden-Popper Oxyfluoride La0.5Sr3.5Fe3O7.5F2.6.

Ruddlesden-Popper (RP) compounds of the general formula (AX)(ABX3)n with their unique sequence of perovskite-like (ABX3) and rock-salt-like units (AX) promise applications in diverse fields such as catalysis and superconductivity. Fluorination of RP oxides often leads to dramatic changes in the material properties, caused by differences in the atomic and electronic structure. While current research focuses on fluorination of n = 1 type RP oxides (A2BO4), n = 3 RP oxyfluorides have remained elusive. We present the synthesis of the first iron-based n = 3 RP oxyfluoride, La0.5Sr3.5Fe3O7.5F2.6, which was obtained from an oxide precursor by topochemical fluorination with poly(vinylidene fluoride). Joint Rietveld refinements of neutron and powder X-ray diffraction data were used to determine the crystal structure. Best results were obtained in the space group Pbca (No. 61) with a = 5.5374(1) Å, b = 5.5441(1) Å, and c = 29.2541(2) Å. The effect of the aliovalent incorporation of fluoride ions is particularly evident with respect to changes in structure and magnetic properties. The magnetic behavior was studied using field- and temperature-dependent magnetization measurements, Mößbauer spectroscopy, and neutron diffraction. Additional magnetic Bragg reflections observed in the room-temperature neutron data were successfully refined in the space group Pbca (61.1.497 in Opechowski-Guccione notation), indicating a G-type antiferromagnetic ordering with a surprisingly high Néel temperature above 300 K. This strong increase of TN by several hundred Kelvin compared to the parent oxide is particularly remarkable.

Physiology, gene expression, and behavior as potential indicators of oxidative stress in piglets

The goal of the current study was to develop a pig model to investigate oxidative stress with a low negative impact on piglet welfare. Four independent trials (A, B, C, and D) were performed using a single intraperitoneal shot of lipopolysaccharide (LPS) as an immune challenge, aiming to assess the minimal LPS dose for piglets of different age to trigger a measurable acute oxidative stress response in healthy animals. In trial A, piglets received an LPS dose of 25 µg/KgBW at 41 days post-weaning (p.w.). In trial B, piglets received 25 µg/KgBW of LPS at 28 days p.w., in trials C And D, piglets were injected with 50 µg/KgBW of LPS at 21 days p.w., respectively. Piglets were randomly allocated either to the T1) Control group with saline solution (Ctrl), or T2) LPS challenge (LPS). The oxidative stress response was measured through the enzymatic activity of glutathione peroxidase (GPx), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT), in both plasma and intestinal tissues. Intestinal gene expression of oxidative stress and inflammatory markers was assessed. Discomfort behaviors (panting, prostration, trembling, and vomits) were also recorded. Plasmatic and intestinal oxidative stress response was inconsistent across the four trials even when the dose and pig age were similar, possibly due to individual variability. Relative gene expression differences of anti-inflammatory cytokines (IL10), oxidation precursor (iNOS), and antioxidant markers (GPx4, MnSOD, and CAT) were detected between Ctrl and LPS treatment (P < 0.05) when assessed. Behavioral observations were sensitive to the LPS dose relative to Ctrl (P < 0.05) in all four trials. These results suggest that behavioral observations can be used as a non-invasive methodology to detect the presence of oxidative stress in pigs in challenging conditions. Behavioral observations were more sensitive than other indicators (i.e., biomarkers and gene expression) in the current study. However, a sensitivity scale system needs to be developed to qualify and rank the impact of oxidative stress in pigs.

Speciation of the Oxide Phase of Molybdenum‐Based HDS Catalysts Enhanced with Organic Additives Using an EXAFS/Raman Coupling Methodology

AbstractThe ability to gain access to the speciation of hydrodesulfurization (HDS) catalysts used for removing sulfur and nitrogen from transportation fuels is becoming a key feature in the understanding and improvement of their catalytic activity with the aim of reducing greenhouse gas emissions of fossil fuels. A novel coupling methodology between Raman spectroscopy and X‐ray absorption spectroscopy (XAS) was developed, which allows for precise qualitative and quantitative analysis of the oxide phase of Mo‐based catalysts. This enabled the detailed study of various impregnation parameters and the characterization of HDS catalysts before sulfidation. To illustrate this methodology, the effects of two additives (triethylene glycol and citric acid) were studied. The results demonstrated that organic additives exert a profound influence on the speciation of oxide precursors of molybdenum‐based catalysts. The presence of these additives enhances the dispersion of Keggin or Dawson heteropolyanions (HPAs) on the support by maintaining a high phosphorus‐to‐molybdenum ratio in solution. This is achieved by two strategies: triethylene glycol (TEG) exhibits a pronounced affinity for alumina hydroxyls, while citric acid compensates for phosphate adsorption through the formation of a stable Mo‐citrate complex.

Total Synthesis of (±)-Baphicacanthcusine A Enabled by Sequential Ring Contractions.

Reported herein is the first total synthesis of the poly-pseudoindoxyl natural product baphicacanthcusine A. The synthesis leverages the oxidative rearrangement of indoles to pseudoindoxyls to install vicinal pseudoindoxyl heterocycles in a diastereoselective manner. Key steps include an acid-mediated cyclization/indole transposition, two diastereoselective oxidative ring contractions, and a site-selective C-H oxygenation. The synthesis of the oxidation precursors was guided by recognition of an element of hidden symmetry. This work provides a foundation for the chemical synthesis of other poly-pseudoindoxyl alkaloids.

Modified structure of vanadium oxide via cadmium doping and in-situ activation for high-performance aqueous zinc ion storage

Vanadium oxides are promising cathode materials for aqueous zinc-ion batteries, but they suffer from severe crystal collapse and poor electrical/ionic conductivity. Herein, we successfully synthesized the designed cadmium-doped, carbon-coated vanadium oxide precursor with abundant oxygen vacancies (Cd0.015V2O3-x@C) using a straightforward one-pot thermal reduction method, followed by in-situ activation to form a high-performance cathode material, Cd0.004V2O5-y·nH2O@C. We find that the interlayered water dramatically reduces the electrostatic force between zinc ions and V2O5-y layers, meanwhile, abundant oxygen vacancies and cadmium doping alter the material’s band structure, resulting in enhanced electronic and ionic conductivities. Leveraging these advantages, the phase transitioned Cd0.004V2O5-y·nH2O@C cathode delivers a remarkably high capacity of 420 mAh/g (0.2 A/g), an excellent rate capability of 198 mAh/g (20.0 A/g), and an outstanding capacity retention of 78.5 % after 3500 cycles (20 A/g). This synergistic structure modification strategy of elemental doping and in-situ activation offers a novel approach to design high-performance vanadium oxide-based cathodes for advanced aqueous batteries.

Improving Amniotic Fluid Index with L-Arginine Supplementation

Background: Oligohydramnios, characterized by a low Amniotic Fluid Index (AFI), is associated with adverse pregnancy outcomes, including fetal growth restriction, preterm labor, and low birth weight. Effective interventions for improving AFI are critical, particularly in resource-limited settings. L-Arginine, a nitric oxide precursor, has shown promise in enhancing uteroplacental circulation and increasing AFI. This study aimed to evaluate the efficacy of L-Arginine supplementation in improving AFI and associated maternal and neonatal outcomes in pregnant women with oligohydramnios in Bangladesh. Methods: This study was conducted at Islami Bank Hospital over one year (July 2023 to June 2024), involving 90 pregnant women diagnosed with oligohydramnios. Participants received daily L-Arginine supplementation, and AFI was measured before and after the intervention. Maternal and neonatal outcomes, including gestational age at delivery, birth weight, and neonatal intensive care unit (NICU) admissions, were recorded. Statistical analysis was performed using paired t-tests, with p &lt; 0.05 considered statistically significant. Results: The mean AFI increased significantly from 5.4 cm (SD ±1.7) before the intervention to 8.6 cm (SD ±2.1) after supplementation, with a mean difference of 3.2 cm (p &lt; 0.001). Low birth weight was observed in 20% of the neonates, while 17.78% required NICU admission. There was a notable improvement in neonatal outcomes with L-Arginine supplementation. Conclusion: L-Arginine supplementation significantly improved AFI and neonatal outcomes, making it a viable intervention for managing oligohydramnios in pregnant women. Further research is recommended to confirm these findings in larger populations.

Ammonium perchlorate catalyzed with novel n-Al modified on ZIF-67 with silane coupling agent: Superior catalytic activity, advanced decomposition kinetics and mechanisms

Ammonium perchlorate (AP) is commonly utilized as an oxidizer in composite solid propellants (CSPs), and the thermal decomposition of AP has a significant impact on the combustion behaviour of CSPs. Aluminum nanoparticles (n-Al) as a prospective metal fuel have received a lot of interest, however properly extracting energy from n-Al remains a great challenge. Native oxide layer limits the energetic performance of n-Al by impeding sufficient combustion and slowing down mass/heat transport. Development of the high energy storage based on metastable intermolecular composite (MIC) is always a desirable way. This group of hybrid materials uses zeolitic imidazole framework (ZIF) as the precursors of the metal oxides as the oxidizers in conventional nanothermite. Coating n-Al on the surface of ZIF-67 with a silane coupling agent to erase or disturb the oxide layer on the n-Al surface improves n-Al combustion. n-Al@ZIF-67 was synthesized and integrated into AP matrix. The catalytic activity of n-Al@ZIF-67 on AP decomposition was assessed via DSC and TGA/DTG. Whereas n-Al@ZIF-67/AP nanocomposite demonstrated decomposition enthalpy of 2350 J/g; pure AP demonstrated 836 J/g, ZIF-67/AP demonstrated 1680 J/g, and n-Al/AP demonstrated 1170 J/g. While Al@ZIF-67/AP nanocomposite demonstrated one decomposition temperature at 327 oC; pure AP decompose at two decomposition stages at 298 oC, and 453 oC. n-Al@ZIF-67/AP showed a violent reaction with high intensity of flame, and micro-explosion occurred due to rapidly disrupted oxide layer that covered Al core. Decomposition kinetics was investigated. n-Al@ZIF-67/AP demonstrated apparent activation energy of 125.3 ± 1.23 kJ/mol compared with 173.16 ± 1.95 kJ/mol for pure AP. Co3O4 NPs as the combustion product from ZIF-67 can expose active surface sites; the ability of adsorption of released NH3 gas, which inhibition AP from decomposition, offering efficient combustion. This work provides a new strategy for advanced CSPs by introducing ZIF-67 to construct bifunctional properties for AP decomposition, and n-Al combustion.