Oxide Fluoride Research Articles

On the thermodynamics of Barium Oxyfluoride precursor in YBCO growth via the MOD process

Abstract Barium Oxyfluoride plays an important role, as a precursor species, in the nucleation and growth of YBa2Cu3O7−δ (YBCO) via the low fluorine metal organic decomposition (MOD low-fluorine) route. In this contribution, we present a study on the thermodynamics of oxyfluoride by processing experimental data on YBCO growth on LaAlO3 (LAO) substrates. The analysis allows one to determine the standard enthalpy and the standard entropy changes for oxyfluoride formation from barium oxide and barium fluoride. To identify the thermodynamically more favorable route to oxyfluoride formation in the MOD low-fluorine process, the free energy change for the formation of the precursor, through reactions involving gas water, has been determined. The free energy of formation via fluoride and water indicates higher stability of oxygen rich oxyfluoride for P HF 2 P H 2 O < 10 − 6 . In the framework of nucleation theory, the present results are needed to study the effect of precursor composition on film orientation.

Synthesis of calcium-based nanofertilizer and its efficacy towards reduction of oxidative stress and fluoride uptake in rice (Oryza sativa L.)

The phytotoxicity of fluoride and its build-up in agricultural plants and subsequently the entry into the food chain is a serious threat to human health. The present study highlighted the green synthesis of calcium oxide nanoparticles (CaO NPs) and characterization using UV-Vis spectrophotometer, TEM, SEM, EDX, XRD, and FTIR. Further, synthesized CaO NPs (0, 10, and 50 mg/L) were applied on fluoride-stressed (10 mg/L) rice seedlings to check its possible ameliorative effects towards growth and fluoride accumulation in different parts of rice seedlings. Characterization revealed that nanoparticles were crystalline (46.72 %) and spherical in shape, with an average diameter of 20–25 nm. Results of the seedling growth analysis revealed that CaO NPs inhibited the translocation of fluoride in rice plants, which in turn decreased the phytotoxicity caused by fluoride, including lipid peroxidation and chlorosis, and enhanced the overall growth of seedlings. The co-exposure of CaO NPs with fluoride also showed a reduction in the fluoride-induced oxidative stress, as demonstrated by lower MDA, O2•- contents, and activity of antioxidant enzymes (CAT, SOD, and POD) as compared to fluoride treatment alone. The application of CaO NPs also restored potassium content in seedlings grown under fluoride stress. Furthermore, the highest reduction of fluoride accumulation by 65 and 76 % in roots and shoots was recorded at 50 mg/L of CaO NPs treatment, respectively. Therefore, the present study clearly indicated the ameliorative potential of CaO NPs towards fluoride stress in rice. However, a field study is needed to establish the social acceptance of this valuable nanofertilizer in fluoride-contaminated areas.

The Efficacy of Nano Magnesium Oxide and Nano Silver Fluoride on Canal Cleanliness and Smear Layer Removal (An In Vitro Study).

The Efficacy of Nano Magnesium Oxide and Nano Silver Fluoride on Canal Cleanliness and Smear Layer Removal (An In Vitro Study).

Constructing 3D porous network channel on PP-based separator to achieve homogeneous deposition of lithium ions for lithium metal battery

Lithium metal anode is broadly regarded as one of the most promising anode materials for batteries due to its extremely high specific capacity, very low redox potential, and mass density. Nevertheless, non-uniform deposition of lithium ions hinder the practical application of lithium metal batteries (LMBs). Herein, it was essential to design a separator with high electrolyte affinity to inhibit the non-uniform deposition of lithium ions. In this work, the wettability and electrolyte uptake of the polypropylene (PP) separator were remarkably improved by introducing reduced graphene oxide (rGO) and polyvinylidene fluoride (PVDF) to the surface of the separator through one-sided coating. The composite separator resulted in lithium ion with high conductivity (1.35 × 10–3 S cm-1) and transfer number (0.63). After assembling the rGO/PVDF@PP separator into the LiFePO4||Li battery and conducting the test, it was found that the specific discharge capacity could still reach 136 mAh g-1 after 100 cycles at 1C. Furthermore, After 1000 h of cycling in the assembled Li‖Li symmetric battery, there is no obvious generation of lithium dendrites on the surface of the lithium metal, indicating the successful suppression of lithium dendrites by the composite separator. This study offers a promising pathway for producing large quantities of new composite separators with high levels of safety.

Composite Electrolytes with Li2CO3‐Free Garnets Achieved by One‐Step Poly(propylene carbonate) Treatment for High‐Rate and Long‐Life Solid Lithium Batteries

AbstractGarnet‐based composite electrolytes show great potential in building high‐energy‐density solid lithium batteries. However, naturally formed Li2CO3 on garnets owing to air exposure hinders the Li‐ion transport and triggers undesirable performance deterioration. Based on the reaction between basic Li2CO3 and poly(propylene carbonate) (PPC) with a product of propylene carbonate (PC), composite electrolytes with homogeneously distributed Li2CO3‐free garnets as well as PC are fabricated in one step without the post‐treatment of garnet powders in both polyethylene oxide (PEO) and polyvinylidene fluoride (PVDF)‐based electrolytes. The formed PC component further decreases the crystallization of PEO and reduces the grain size of PVDF, leading to improved ion transport in PEO and the suppression of PVDF dehydrofluorination. Consequently, the PPC‐treated garnets enable high ionic conductivities of 3.40 × 10−4 and 1.75 × 10−4 S cm−1 at 30 °C, respectively, in PEO:garnet and PVDF:garnet electrolytes, as well as great electrochemical stability against Li‐metal with a lifespan over 1000 h in Li symmetrical cells at 0.1 mA cm−2. Superior stable cycles are thus realized in both LiFePO4|PEO:garnet|Li and LiNi0.6Co0.2Mn0.2O2|PVDF:garnet|Li cells. These above results demonstrate that the one‐step treatment used here helps the enhancement of Li‐ion transport in composite electrolytes, thus essential for building high‐rate and long‐life solid lithium batteries (SLBs).

Effect of oleic acid modified GO‐LaF3 on lubrication characteristics of 10# white oil

AbstractTo study the synergistic lubricating effects of graphene oxide (GO) and lanthanum fluoride (LaF3), and find a new anti‐wear additive, oleic acid surface‐modified graphene oxide‐lanthanum fluoride (OA‐GO‐LaF3, OGL) composite nano‐additive was prepared by hydrothermal method by using oleic acid as the modifier. The morphology, structure, composition, element valence, thermal stability and tribological properties of nano additives were characterised by a series of modern characterisation methods. Results show that OGL has a higher degree of graphitization, smaller particle size, more homogeneous disperse, higher LaF3 load and stronger thermal stability than that of GL. The tribological properties of OGL which is modified by oleic acid are better than unmodified GL. Analysis of the friction mechanism shows that both OGL and GL can generate LaF3 physical adsorption films through adsorption during the friction process and tribochemical reactions film containing lanthanum compounds, carbon oxide compounds, and iron oxide compounds on the friction surface. These physical adsorption films and chemical reaction film can improve lubrication.

The influence of sodium fluoride on the dissolution kinetics of metallic titanium in citric acid solution using the rotating disc method

This study reports the effect of sodium fluoride on the dissolution kinetics of pure metallic titanium in a citric acid solution. The effects of sodium fluoride concentration, citric acid concentration, temperature, stirring speed, and disc surface area were examined. The dissolution rate of titanium increases strongly with increasing citric acid and sodium fluoride concentrations. Fluoride ions react with hydrogen ions to form hydrofluoric acid, which removes the passive layer of titanium dioxide. An increase in the concentration of NaF and acid causes the formation of a brown layer on the surface of titanium. X-ray diffraction and SEM-EDX analyses showed that the layer composition is mostly of titanium fluoride (TiF3) and titanium fluoride oxide (TiOF2). A mixed kinetic model with an activation energy of 26.4 kJ/mol can be used to explain the reaction kinetics.

Phase Equilibrium Study of Rare Earth Oxide–Fluoride Salt System: A Review

The applications of rare earth metals and alloys are becoming increasingly widespread and there is a strong market demand. Currently, most of the production enterprises adopt the fluoride–oxide system for electrolytic preparation of rare earth metals and alloys. The solubility of rare earth oxides in molten salt directly affects the selection of operational parameters in the electrolysis process. When the added amount of RE2O3 is less than its solubility, it leads to a decreased electrolytic efficiency. Conversely, an excessive amount of oxide is prone to settle at the bottom of the electrolytic cell, impeding smooth production. The RE2O3 solubility in the fluoride salt can be represented by the phase equilibrium of the RE2O3-REF3-LiF system. The isothermal lines in the primary phase field of rare earth oxide represent the solubility of the oxide in the fluoride salt at the corresponding temperature. This paper outlines the research methods and experimental results on the phase equilibria of the RE2O3-REF3-LiF system. The characteristics and existing problems in the current phase equilibrium study are analyzed. The solubility data of RE2O3 are expressed in the forms of ternary and pseudo-binary phase diagrams of the RE2O3-REF3-LiF system, providing theoretical guidance for the establishment of an accurate and reliable rare earth electrolysis system database and the optimization of electrolytic processes.

Effect of zinc nanoparticles on the mechanical properties and stability of the resin-dentin bonded interface

To evaluate the effect of zinc oxide and zinc fluoride nanoparticle solution (ZNS) as pretreatment on the mechanical properties and stability of resin-dentin bonded interface. Pretreatment solutions were applied after phosphoric acid: 5 and 10% Zinc Oxide (ZO5; ZO10); 1.5 and 3% Zinc Fluoride (ZF1.5 and ZF3); 0.2% chlorhexidine (CHX-positive control) and no pretreatment (NC-negative control). The treated teeth were restored and stored for 24 h and 12 m prior to microtensile bond strength (µTBS) testing (n = 8). Failure mode, nanohardness (NH) and young’s modulus (YM) (n = 3) were also evaluated. In situ zymography (n = 3) and interface morphology (n = 3) were evaluated after 24 h. The antibacterial activity was determined by minimum inhibitory (MIC) and bacterial (MBC) concentration. The µTBS was evaluated by two-way mixed ANOVA and NH and YM data were analyzed by two-way mixed repeated-measures ANOVA (α = 0.05). In situ zymography, interface morphology, MIC and MBC were descriptively analyzed. The µTBS of ZF3, ZO10 and CHX was maintained over time, while for ZF1.5 and Z05 it was increased. Mixed failures were the most prevalent for all groups. ZF3 presented higher values of NH and YM with incorporation of nanoparticles being observed within the hybrid layer on the interface morphology image. CHX presented the lowest enzymatic activity followed by ZO5. MIC and MBC for ZO were 62.5 µg/mL and ZF 3.25 µg/mL, respectively. Pretreatment with ZNS, specially zinc fluoride, seems to be a promising method to increase the longevity of restorations.

Post-annealing-free BaOxFy/LiF-based stack electron-selective contacts for high efficiency crystalline silicon solar cells featuring ultra-low contact resistivity

In silicon heterojunction and tunnel oxide passivating contact crystalline silicon (c-Si) solar cells based on successful passivating contacts technologies, an annealing activation step is indispensable to achieve a suitably low contact resistivity (ρc), which is a costly and non-ideal process. Here, combined with a calcium aluminium (Ca:Al) alloy electrode, a low work function barium oxide and lithium fluoride (BaOxFy/LiF) stack electron-selective contact (ESC) without an annealing activation step on c-Si solar cells clinches an ultra-low ρc of 1.4 mΩ·cm2 delivering a power conversion efficiency (PCE) of 20.5 %. The BaOxFy/LiF/Ca:Al stack structure is built by BaOx/LiF/Ca/Al hybrid structure via a facile continuous thermal evaporation process. As a proof of concept, the stacked BaOxFy/LiF/Ca:Al/Al contact is applied to the rear side of c-Si solar cells, achieving a PCE of 20.5 % with an open-circuit voltage of 625.7 mV, an impressive fill factor of 83.5 % and a short-circuit current density of 39.2 mA/cm2. With the aid of a transient photovoltage setup, the carrier recombination mechanism of the stacked BaOxFy/LiF/Ca:Al structure is explored. This work demonstrates an alternative idea for undoped ESCs, showing potential for next-generation cost-effective ultrathin-slice c-Si solar cells (∼80 μm) with high efficiency, and low-parasitic light absorption losses.

Technological Advances and Market Developments of Solid-State Batteries: A Review.

Batteries are essential in modern society as they can power a wide range of devices, from small household appliances to large-scale energy storage systems. Safety concerns with traditional lithium-ion batteries prompted the emergence of new battery technologies, among them solid-state batteries (SSBs), offering enhanced safety, energy density, and lifespan. This paper reviews current state-of-the-art SSB electrolyte and electrode materials, as well as global SSB market trends and key industry players. Solid-state electrolytes used in SSBs include inorganic solid electrolytes, organic solid polymer electrolytes, and solid composite electrolytes. Inorganic options like lithium aluminum titanium phosphate excel in ionic conductivity and thermal stability but exhibit mechanical fragility. Organic alternatives such as polyethylene oxide and polyvinylidene fluoride offer flexibility but possess lower ionic conductivity. Solid composite electrolytes combine the advantages of inorganic and organic materials, enhancing mechanical strength and ionic conductivity. While significant advances have been made for composite electrolytes, challenges remain for synthesis intricacies and material stability. Nuanced selection of these electrolytes is crucial for advancing resilient and high-performance SSBs. Furthermore, while global SSB production capacity is currently below 2 GWh, it is projected to grow with a >118% compound annual growth rate by 2035, when the potential SSB market size will likely exceed 42 billion euros.

Effects of Y and Ho doping on microstructure evolution during oxidation of extraordinary stable Hf-B-Si-Y/Ho-C-N films up to 1500 °C

Hard, and optically transparent amorphous Hf6B12Si29Y2C2N45 and Hf5B13Si25Ho3C2N48 films were prepared by reactive pulsed dc magnetron co-sputtering and annealed up to 1500 °C in air. The evolved microstructures were studied by X-ray diffraction and transmission electron microscopy to understand the Y- and Ho– doping effects on thermal stability and oxidation behavior. A three-layered microstructure developed in both annealed films. A fully oxidized layer formed at the top surface consisting of cubic fluorite Hf(Y/Ho)O2 nanoparticles embedded in an amorphous SiOx-based matrix. The oxide layer is about 36 % thinner compared to undoped films with similar composition [1]. A recrystallized structure formed at the bottom of both films composed mainly of Hf(Y/Ho)N and α-/β-Si3N4. All Hf(Y/Ho)N in the middle layer was oxidized producing vertically oriented Hf(Y/Ho)O2 nanocolumns surrounded by Si3N4 nanocrystalline. The Y- and Ho– doping found to stabilize the cubic fluoride oxide structure and promoted its (1 1 1) columnar texture. The oxidation mechanism of Si3N4 nanodomains occurs via formation of β-SiO2 first followed by its transformation to amorphous SiOx. It is suggested that substitution of Hf4+ with Y3+ and Ho3+ ions within the Hf(Y/Ho)O2 formed an anion vacancy defect structure to preserve charge neutrality affecting the oxidation mechanism in the doped films.

Amorphization of Inorganic Solid Electrolyte Interphase Components and Its Impact on Enhancing Their Transport and Mechanical Properties.

The safety and cycle life of lithium-ion batteries (LIBs) are largely determined by the solid electrolyte interphase (SEI) formed on the surface of the anode. However, there is still a lack of understanding regarding the structure and properties of the individual SEI components. Among others, lithium oxide (Li2O), lithium carbonate (Li2CO3), and lithium fluoride (LiF) are known to be the main components of the inorganic SEI layer in conventional LIBs, but their intrinsic protective roles remain controversial. Herein, we present the transformational effects of their amorphous phase on the mechanical and transport characteristics, based on first-principles calculations. Our studies clearly demonstrate that their amorphous phases exhibit significantly improved Li-ion conductivity when compared to the crystalline structures. Additionally, among them, amorphous LiF emerges as a frontrunner for fast Li+ ion transportation, reversing the conventionally understood hierarchy. Under ambient conditions, the amorphous phases of LiF, Li2O, and Li2CO3 are thermodynamically unstable and tend to undergo recrystallization. However, this work highlights that exceptionally ductile and resilient amorphous phases can form if SEI formation and growth would involve some admixing of lithiophilic impurities like nitrogen (N) within the host matrices.

Synthesis and Ionic Conductivity of Fluoride–Oxide Composites in NdF3–Nd2O3 and NdF3–SrF2–Nd2O3 Systems

Synthesis and Ionic Conductivity of Fluoride–Oxide Composites in NdF3–Nd2O3 and NdF3–SrF2–Nd2O3 Systems

Effect of Gadolinium Oxide and Gadolinium Fluoride in Borophosphate Glasses Doped with Tb2O3 Content

The melt-quenching process synthesized gadolinium oxide and fluoride in borophosphate glasses doped with terbium ions (Tb3+). The effect of fluoride compounds and their impacts on physical, optical, and luminescent properties have been investigated. The glasses absorbed near-infrared, visible light, and ultraviolet photons. The bright green emission circa 542 nm via the 5D4 → 7F5 radiative state of Tb3+ originated. Depending on the excitation, there are several sorts of ultraviolet, visible light, and X-ray. The values of decay time are in the order of milliseconds (ms). The Gd3+-Tb3+ energy transfer is vital in green emission under 275 nm excitation. According to the results obtained in this work, the developed glasses can be suitable candidates for green emission medium.

Wearable Nano-Based Gas Sensors for Environmental Monitoring and Encountered Challenges in Optimization.

With a rising emphasis on public safety and quality of life, there is an urgent need to ensure optimal air quality, both indoors and outdoors. Detecting toxic gaseous compounds plays a pivotal role in shaping our sustainable future. This review aims to elucidate the advancements in smart wearable (nano)sensors for monitoring harmful gaseous pollutants, such as ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2), hydrogen sulfide (H2S), sulfur dioxide (SO2), ozone (O3), hydrocarbons (CxHy), and hydrogen fluoride (HF). Differentiating this review from its predecessors, we shed light on the challenges faced in enhancing sensor performance and offer a deep dive into the evolution of sensing materials, wearable substrates, electrodes, and types of sensors. Noteworthy materials for robust detection systems encompass 2D nanostructures, carbon nanomaterials, conducting polymers, nanohybrids, and metal oxide semiconductors. A dedicated section dissects the significance of circuit integration, miniaturization, real-time sensing, repeatability, reusability, power efficiency, gas-sensitive material deposition, selectivity, sensitivity, stability, and response/recovery time, pinpointing gaps in the current knowledge and offering avenues for further research. To conclude, we provide insights and suggestions for the prospective trajectory of smart wearable nanosensors in addressing the extant challenges.

Synergistic Antimicrobial Effect of Cold Atmospheric Plasma and Redox-Active Nanoparticles.

Cold argon plasma (CAP) and metal oxide nanoparticles are well known antimicrobial agents. In the current study, on an example of Escherichia coli, a series of analyses was performed to assess the antibacterial action of the combination of these agents and to evaluate the possibility of using cerium oxide and cerium fluoride nanoparticles for a combined treatment of bacterial diseases. The joint effect of the combination of cold argon plasma and several metal oxide and fluoride nanoparticles (CeO2, CeF3, WO3) was investigated on a model of E. coli colony growth on agar plates. The mutagenic effect of different CAP and nanoparticle combinations on bacterial DNA was investigated, by means of a blue-white colony assay and RAPD-PCR. The effect on cell wall damage, using atomic force microscopy, was also studied. The results obtained demonstrate that the combination of CAP and redox-active metal oxide nanoparticles (RAMON) effectively inhibits bacterial growth, providing a synergistic antimicrobial effect exceeding that of any of the agents alone. The combination of CAP and CeF3 was shown to be the most effective mutagen against plasmid DNA, and the combination of CAP and WO3 was the most effective against bacterial genomic DNA. The analysis of direct cell wall damage by atomic force microscopy showed the combination of CAP and CeF3 to be the most effective antimicrobial agent. The combination of CAP and redox-active metal oxide or metal fluoride nanoparticles has a strong synergistic antimicrobial effect on bacterial growth, resulting in plasmid and genomic DNA damage and cell wall damage. For the first time, a strong antimicrobial and DNA-damaging effect of CeF3 nanoparticles has been demonstrated.

Effect of alkali/alkaline modifiers on Pr3+ ions doped lead boro-tellurite glasses for lasing material applications

Pr3+ incorporated Lead boro-tellurite glasses were prepared and their structural and optical performance was explored through absorption, luminescence and decay measurements. The oscillator strengths deliberated from the absorption spectral features were used to estimate the Judd-Ofelt (J-O) intensity parameters. The emission spectral features recorded monitoring an excitation at 610 nm exhibits two intense peaks located at 496 nm; 3P0 → 3H4 transition pertains to blue emission and similarly at 543 nm; 3P1 →3H5 transition refers to green emission. Radiative parameters for the 3P0 → 3H4, 3P0→3H5 and 3P0 →3F2 transitions are evaluated and the modifications observed by changing the alkali/alkaline modifiers on the Lead boro-tellurite glasses were reported. The glasses lie in the province of intense blue & green emission is observed through CIE diagram. Especially glasses with higher correlated color temperature values mainly used for roads covered with fog and also for tunnel lighting purposes. Radiative parameters consequent to the salient emission bands elucidate the aptness of the glass materials for the manufacture of photonic equipment's. Decay studies explored the non-exponential behaviour. It is concluded that, modifiers activated Pr3+ doped oxide and oxy fluoride incorporated glass system is aptly appropriate for optoelectronic gadget applications.

Ce & F multifunctional modification improves the electrochemical performance of LiCoO2 at 4.60 V

Lithium cobalt oxide (LiCoO2) is proverbially employed as cathode materials of lithium-ion batteries attributed to the high theoretical capacity, and currently, it is developing towards higher cut-off voltages in the pursuit of higher energy density. However, it suffers from serious structural degradation and surface side reactions, in particular, at the voltage above 4.60 V, leading to rapid decay of the battery life. Taking into account the desirable oxygen buffering property and the fast ion mobility characteristic of cerium oxide fluoride, in this work, we prepared Ce & F co-modified LiCoO2 by using the precursors of Ce(NO3)3·6H2O and NH4F, and evaluated the electrochemical performance under voltages exceeding 4.60 V. The results indicated that the modified samples have multiphase heterostructure of surface CeO2−x and unique CeOF solid solution phase. At 3.0–4.60 V and 25 °C, the preferred sample LCO-0.5Ce-0.3F has a high initial discharge specific capacity of 221.9 mA h g−1 at 0.1 C, with the retention of 80.3% and 89.6% after 300 cycles at 1 and 5 C, comparing with the pristine LCO (56.4% and 22.6%). And at 3.0–4.65 V, its retention is 64.0% after 300 cycles at 1 C, versus 8.5% of the pristine LCO. Through structural characterizations and DFT calculations, it suggests that Ce4+ & F− co-doping suppresses the H3 to H1/3 irreversible phase transition, stabilizes the lattice structure, and reduces the redox activity of the lattice oxygen by modulating the Co 3d–O 2p energy band, consequently improving the electrochemical performance of LiCoO2 at high voltages.

Gas-phase epoxidation of Hexafluoropropene using molecular oxygen and alkali doped CuO catalyst: Mechanism and kinetics

The study investigated the partial oxidation of hexafluoropropene over CuO catalyst with molecular oxygen in a continuous flow fixed bed reactor. The catalysts were characterized using various techniques, and the results confirmed catalyst's structure-reactivity correlation. The major products were hexafluoropropene oxide (HFPO) and carbonyl fluoride, with minor trifluoroacetyl fluoride produced when the catalyst had significantly declined in primary activity. The maximum selectivity of 52.5% HFPO was obtained at 13.4% hexafluoropropene conversion at 4.5 bar and 453 K. The proposed redox mechanism kinetic model was in adequate agreement with the experimental data (R2 = 0.97 for COF2 and 0.67 for HFPO).