Salt Method Research Articles

MXene: A Roadmap to Sustainable Energy Management, Synthesis Routes, Stabilization, and Economic Assessment.

MXenes with their wide range of tunability and good surface chemistry provide unique and distinctive characteristics offering potential employment in various aspects of energy management applications. These high-performance materials have attracted considerable attention in recent decades due to their outstanding characteristics. In the literature, most of the work is related to specific methods for the preparation of MXenes. In this Review, we present a detailed discussion on the synthesis of MXenes through different etching routes involving acids, such as hydrochloric acid, hydrofluoric acid, and lithium fluoride, and non-acidic alkaline solution, electrochemical, and molten salt methods. Furthermore, a concise overview of the different structural, optical, electronic, and magnetic properties of MXenes is provided corresponding to their role in supporting high thermal, chemical, mechanical, environmental, and electrochemical stability. Additionally, the role of MXenes in maintaining the thermal management performance of photovoltaic thermal systems (PV/T), wearable light heaters, solar water desalination, batteries, and supercapacitors is also briefly discussed. A techno-economic and life cycle analysis of MXenes is provided to analyze their sustainability, scalability, and commercialization to facilitate a comprehensive array of energy management systems. Lastly, the technology readiness level of MXenes is defined, and future recommendations for MXenes are provided for their further utilization in niche applications. The present work strives to link the chemistry of MXenes to process economics for energy management applications.

Growth mechanism of high-aspect ratio zirconia whisker by molten salt method

Growth mechanism of high-aspect ratio zirconia whisker by molten salt method

The effect of synthesis temperature on structural, morphological, and band gap energy of plate-like Bi4Ti2.95V0.05O12 prepared by molten NaCl/KCl salt method

Vanadium (V)-doped Bi4Ti3O12 compound is reported to have good photocatalyst properties; however, efforts still need to improve the ability of the photocatalyst through various strategies, such as controlling the morphology and particle size. The molten salt method is one of the simple synthesis methods reported successful in synthesizing Bi4Ti3O12 compounds with plate-like/sheet morphology and reported having good photocatalyst activity. One of factor influenced to particle compound obtained by molten salt method is synthesis temperature. Therefore, in this work, V-doped Bi4Ti3O12 (Bi4Ti2.95V0.05O12) was prepared through the molten salt NaCl/KCl method at various synthesis temperatures: 700, 750, and 800?C and the effect of temperature synthesized on (a) structural (b) morphological, and (c) band gap energy were studied. These studies used X-ray diffraction data (diffractogram), scanning electron microscope (SEM) and diffuse reflectance ultraviolet-visible spectroscopy. The diffractograms showed that the target compound was successfully obtained at all temperature synthesis. The crystallographic data indicated that temperature synthesis determined the lattice parameter values. However, there are no clear trend changes that is possibly due to changes in the valence of the V atom. The synthesis temperature also causes increasing the crystallite size but does not affect the crystallinity samples. SEM images showed that all samples had plate-like/sheets morphology and the particle size became larger at higher temperature. It indicated that the particle growth rate was faster than nucleation rate. Meanwhile, the result of Kubelka-Munk calculation showed that all samples had relatively same band gap energy value (Eg(1) was ~ 2.90, and Eg(2) was ~1.85 eV.

Microstructure and performance of carbon fiber reinforced aluminum matrix composites with molybdenum carbide coating on carbon fibers

In this work, a molybdenum carbide coating on the surface of short carbon fibers prepared using molten salt method was proposed to ameliorate the interfacial bonding and improve the performance of carbon fiber/Al composites. The carbon fiber/Al composites were produced using vacuum hot pressing. The characteristics of molybdenum carbide coating were analyzed. Besides, the microstructures, bending strength and thermal properties of the carbon fiber/Al composites were explored. Furthermore, the interfacial thermal resistance of the composites was investigated in relation to theoretical evaluations derived from the combined Maxwell-Garnett effective medium approach and acoustic mismatch model schemes. The results indicated that a homogeneous Mo2C coating with a thickness of 0.5 μm was obtained by proper molar ratio of carbon fibers, MoO3 and chloride salts mixture and heated at 1000 °C for 60 min. The Mo2C coating greatly enhanced the bond between the aluminum matrix and carbon fiber, leading to improvements in the densification behavior and bending strength of the coated composites. The enhanced thermal properties including improved thermal conductivity and reduced coefficient of thermal expansion (CTE) were also achieved by the Mo2C coating. The in-plane thermal conductivity of 60 vol.% Mo2C-coated carbon fiber/Al composite was 221 W·m−1·K−1 enhanced by 92% compared to that of uncoated composite and the CTE was 6.0 × 10–6 K−1 which was suitable for electronic packaging materials.

In-situ preparation and ablative resistance of multicomponent refractory carbide ceramic gradient coatings

In this work, the gradient multicomponent carbide ceramic coatings were prepared in-situ on graphite matrix using the molten salt method, and their high temperature ablation resistance was investigated. Our results demonstrate the successful preparation of (HfTi)C, (HfTiZr)C, and (HfTiZr)C–TaC ceramic coatings with a gradient distribution on the graphite matrix by altering the types of raw materials. Thermodynamic calculations and analyses indicate that the smaller the Gibbs free energy gap between different carbides, the easier the solid solution multicomponent ceramic coating is formed. After 200 s of oxy-acetylene torch ablation, it was observed that the (HfTi)C, (HfTiZr)C, and (HfTiZr)C–TaC coatings effectively protected the graphite matrix with mass ablation rates of 6.47 mg s−1, 0.61 mg s−1, and 0.51 mg s−1, respectively. The low mass loss of (HfTiZr)C and (HfTiZr)C–TaC coatings can be attributed to the synergistic protective effect of different oxides formed by oxidation of different elements.

Effect of Carbon Support on the Properties of Fe, N, S Co-Doped ORR Catalysts Prepared by Molten Salt Method

In recent years, the development of sustainable and environmentally friendly catalysts for various electrochemical processes has become a major focus in the fields of energy storage and fine chemicals. Efficient and cost-effective oxygen reduction reaction (ORR) catalysts are crucial for the advancement of fuel cells and metal-air batteries. This study explores the use of rice husk-based porous carbon (RHPC) with a hierarchically porous structure as a support material for sustainable ORR catalysts. The performance of RHPC was compared with other commercial carbon materials, such as acetylene black (AB) and coconut shell carbon (YP-50), evaluating key properties including particle size, specific surface area, oxygen-containing functional groups, degree of graphitization, and hydrophilicity/hydrophobicity. Compared to AB, which has higher conductivity, and YP-50, which has a greater abundance of oxygen functional groups, RHPC demonstrated significant advantages as a catalyst support. The resulting Fe-NS/RHPC catalyst exhibited high activity (E1/2 = 0.858 V vs RHE, J = 4.83 mA cm−2), outperforming the standard Pt/C (E1/2 = 0.844 V vs RHE, J = 4.99 mA cm−2). When tested in a liquid Zn-air battery, the Fe-NS/RHPC catalyst achieved a peak power density of 116.2 mW cm−2 and a capacity of up to 792.5 mAh g−1.

Quality changes due to refrigerated storage in a traditional dry-cured pork belly salted with glasswort or KCl as partial substitutes for NaCl.

Glasswort represents a novel alternative to KCl for replacing sodium in meat products. To evaluate the effects of Na reduction on the quality changes of a traditional dry cured belly due to storage, fresh bellies were dry-salted with 2% NaCl (BCON), with 2% of a mixture containing 50% NaCl and 50% KCl (BKCl) or with 1% of a mixture of 90% NaCl and 10% powdered glasswort (BGW), dry-cured, sliced, vacuum packaged and stored under refrigeration for 60 days. The BKCl and BGW bellies were lower in sodium by one-third to one-half compared to BCON (with 1.6 g Na/100 g). Neither BKCl, nor BGW significantly differed from BCON in free fatty acids (FFA) before and after storage, whereas BGW showed almost twice as much 2-methylbutanal content as BCON. All bellies showed microbiological stability during storage. Micrococcaceae was the most abundant microbial group with values of 105 to 106 colony-forming units g-1. The BGW presented higher Micrococcaceae counts (approximately one log unit) but lower microbial biodiversity than BCON. The two alternative dry salting methods reduced the sodium content in bellies, at the same time as ensuring chemical and microbiological stability during refrigerated vacuum storage. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Molten salt synthesis of MnO2/Mn2O3 composite as a high-performance cathode material for rechargeable button zinc‑manganese ultra-high temperature battery

Herein, a novel rechargeable button zinc‑manganese ultra-high temperature battery is first reported for the efficient utilization and conversion of thermal and electrical energy. The battery system uses zinc anode, Zn-K-Cl molten salt electrolyte and MnO2/Mn2O3 composite cathode to work at 300 °C. In this study, MnO2/Mn2O3 composites were synthesized by molten salt method, and the crystal structure of the materials was adjusted by adding reduced graphene oxide (rGO). The results showed that the spherical nanoparticles and nanobelts of MnO2/Mn2O3 composite cathode materials increased the active sites and ion transport channels of the electrochemical reaction, thus providing high coulombic efficiency. By modifying with rGO, the MnO2/Mn2O3 (Mn-O-2) composite cathode material exhibits excellent electrochemical performance in the button zinc‑manganese ultra-high temperature battery. The as-prepared button ultra-high temperature battery exhibits a relatively high specific capacity (300 and 175 mAh g−1 at 1 mA cm−2 and 30 mA cm−2) and competent cyclability (> 95 % coulombic efficiency after 50 cycles). This work firstly and systematically reveals the role of the Mn cathode materials and shows that the application in button molten salt batteries.

Spontaneous Electrochemical Reconstruction of NiNb2O6@C for High-Rate Lithium-Ion Batteries

Niobium oxides are widely active in the arena of lithium-ion batteries due to their distinctive structure and rapid charging capability, nevertheless facing the serious challenge from their inherently low electrical conductivity. Herein, a molten salt method is proposed to prepare nickel niobate (NiNb2O6) anode materials for lithium-ion batteries, and a carbon coating derived from mesophase pitch is fabricated to construct NiNb2O6@C composites. Importantly, NiNb2O6@C undergoes spontaneous electrochemical reconstruction to generate metallic Ni and amorphous Nb2O5 during the initial charge/discharge cycle. The presence of the outer carbon layer not only serves as a uniform conductive coating to improve the conductivity and thereby deliver superior rate performance, but also effectively inhibits the stripping of Ni0 to guarantee a great cycling stability. The synergistic effects of the dual conductive interfaces, consisting of the carbon layer and the Mott-Schottky heterojunction between amorphous Nb2O5 and metallic Ni, culminate in exceptional electrochemical performance. Specifically, NiNb2O6@C-10% delivers impressive specific capacity of 436.3 mAh g−1 at 0.5C and conspicuous cycling stability, maintaining 86.3% capacity retention after 800 cycles at 10C. This work underscores the substantial potential of nickel niobate anode materials in advancing the development of next-generation lithium-ion batteries.

A simple and feasible method for preparing chromium carbide coating on graphite through binary NaCl-KCl molten salt

Due to excellent high temperatures resistance and wear resistance, graphite showed great potential apply in refractory materials. However, the porosity defects caused by the layered stacked structure of graphite would lead to easy permeability, which would result in reducing material’s lifetime. Surface coating technology was considered to be an ideal method to solve the problems through a stable coating on the surface of graphite. But existing methods have some disadvantages, such as high-cost and complex processes. In this work, a simple, low-cost and green molten salt method was designed. This method successfully prepared a Cr7C3 coating on the graphite surface. The effect of reaction time and temperatures on the chromium carbide coating was investigated by SEM and EDS. The results showed that the thickness of the coating layer increased gradually with the increase in reaction time or reaction temperature, and finally stabilized at about 8 μm. In addition, the reasons behind the formation of Cr7C3 coatings were discussed in terms of both the molten salt reaction and Gibbs free energy, as well as the effect of the coating structure on adhesion. Based on this method, it could not only effectively address the structure defects of graphite, but also showed simple preparation processes and low cost, which would promote the development of graphite materials in high-temperature resistant materials.

A novel low-cobalt single-crystal lithium-rich manganese-based layered oxide cathodes with enhanced electrochemical performances

Single-crystal (SC) morphology of lithium-rich manganese-based layered oxides (LLOs) cathode materials, due to their stable structure and absence of excess grain boundaries, holds promise for addressing issues such as oxygen loss and poor cycle stability in traditional polycrystalline (PC) cathode materials. In this study, a low-cobalt SC LLOs cathode material with excellent electrochemical performances is successfully synthesized by the molten salt method and the appropriate calcination temperature. The SC LLOs cathode calcined at 900 °C exhibits superior physical properties. Its particle size of D50 is 332 nm, which results in an optimal average Li+ diffusion coefficient (DLi+) value of 10−10.29 cm2 s−1. At C/10 (1C = 250 mA g−1), it delivers the first discharge capacity of 242 mAh g−1 with an initial Coulombic efficiency (ICE) of 73.8 %. After 200 cycles at C/3, it maintains the capacity retention of 80.8 %. This work extensively elaborates on the influence of calcination temperature on the particle size, physical properties and electrochemical stability of low-cobalt SC LLOs cathode materials, which would provide effective guidance for the design of high-performance SC cathode materials.

Molecular docking and molecular dynamics simulation of wheat gluten-derived antioxidant peptides acting through the Keap1-Nrf2 pathway.

In our previous study, we successfully identified five peptides from wheat gluten: Ala-Pro-Ser-Tyr (APSY), Leu-Tyr (LY), Pro-Tyr (PY), Arg-Gly-Gly-Tyr (RGGY) and Tyr-Gln (YQ). Molecular docking and molecular dynamics simulation methods were employed to investigate the interaction between these antioxidant peptides and the Kelch-like ECH-associated protein 1 (Keap1 protein), revealing the molecular mechanism of their non-competitive binding. In addition, the total antioxidant capacity of the five peptides was determined using the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) method. The affinities of APSY, LY, PY, RGGY and YQ were -8.9, -8.3, -8.5, -9.1 and - 7.9 kcal mol-1, respectively. The five peptides effectively bound to Keap1 protein through hydrogen, π-σ, π-alkyl and alkyl interactions. Significant roles were observed for the P1 pocket residue ARG-415 and the P3 pocket residue ALA-556 in the interactions of the Keap1-peptide complexes. Molecular dynamics simulations further elucidated the dynamic process of peptide binding to the Keap1 protein. All five peptides formed stable complexes with Keap1 protein, with van der Waals forces playing crucial roles in these complex systems, indicative of the peptides' strong binding ability to Keap1 protein. The van der Waals forces were -178.74, -123.11, -134.36, -132.59, and -121.44 kJ mol-1 for the Keap1-APSY, Keap1-LY, Keap1-PY, Keap1-RGGY and Keap1-YQ complexes, respectively. These peptides exhibited excellent antioxidant effects. Among them, the YQ peptide exhibited the highest total antioxidant capacity, with an activity value of 1.18 ± 0.06 mmol Trolox equivalent (TE) L-1 at a concentration of 0.10 mg mL-1. The RGGY, PY, LY and APSY peptides followed in descending order, with activity values of 0.91 ± 0.05, 0.72 ± 0.06, 0.62 ± 0.04 and 0.60 ± 0.05 mmol TE L-1, respectively. These results unveiled the molecular mechanism by which the five antioxidant peptides act on active pockets through the Keap1-Nrf2 signaling pathway, providing a theoretical basis for the development of antioxidants. © 2024 Society of Chemical Industry.

Preparation of high-density green body based on binder jetting 3D printing using spheroidized SiC powder

Silicon carbide (SiC) ceramic stands as a critical material in the realm of high-performance engineering ceramics. However, Crafting SiC ceramics with intricate structures and superior mechanical properties presents notable challenges in shaping, sintering, and processing. Binder jetting (BJ) additive manufacturing has the outstanding advantages of high forming efficiency and no thermal deformation, especially suitable for printing complex structure SiC components.; however, BJ printed green bodies often exhibit low density, resulting in high residual silicon content and diminished strength of the final components. In this work, we introduce a novel strategy to fabricate high-strength SiC components with complex geometries by improving the density of printed SiC green bodies. This method involves modifying the morphology of SiC powder through the molten salt method to increase the density of BJ 3D printed green bodies from 1.24 ± 0.13 g/cm³ to 2.01 ± 0.03 g/cm³, followed by a reactive melt infiltration process. The resulting RB-SiC ceramics display exceptional flexural strength, averaging 280.60 ± 33.05 MPa, and an elastic modulus of 294.67 ± 4.90 GPa. These values represent some of the highest for flexural strength and elastic modulus reported among 3D-printed SiC composites. With its robust mechanical performance and streamlined fabrication process, this strategy holds substantial promise for the production of structural SiC ceramics.

Synthesis and characterization of Mn-doped g-C3N4/ZnO nanocomposite for photocatalytic degradation and antibacterial activity applications

The current study involves the investigation of photocatalytic degradation of malachite green dye and antibacterial activity by Mn-doped g-C3N4/ZnO nanocomposite. The molten salt method was used to synthesize g-C3N4 and Mn-doped g-C3N4. The co-precipitation method was used to synthesize ZnO, g-C3N4/ZnO, and Mn-doped g-C3N4/ZnO. The nanocomposite was effectively synthesized and analyzed by XRD, FT-IR, UV–Vis DRS, PL, SEM with EDAX, HR-TEM, BET, EIS and lifetime analysis. Photocatalytic degradation activity was tested under different conditions, namely initial concentration of malachite green, solution pH, catalyst dosage, and time. When Mn is doped with g-C3N4, it improves the ability of g-C3N4/ZnO composite to remove and degrade 10 ppm of malachite green by about 13 % in 90 min under simulated sunlight exposure. The synthesized photocatalyst degrades 10 ppm of malachite green with a degradation efficiency of 95.6 % at 90 min and also 100 ppm of the same dye was degraded by 80.8 % in 90 min. The study of photocatalytic mechanism showed that reactive oxygen species, such as holes and superoxide radicals, are very important in breaking down dyes. Under dark condition, the Mn-doped g-C3N4/ZnO nanocomposite has adsorption and desorption efficiencies of ∼70 % and ∼50 %, respectively in 10 ppm dye. The reusability and stability of the nanocomposite was retained for up to five consecutive photocatalytic degradation processes. The antibacterial property of the synthesized nanocomposite was also investigated. The composite has shown activity against S. aureus and E. coli. This research shows that the synthesized catalyst has good photocatalytic as well as antibacterial activities.

Synthesis, phase structure and dielectric properties of CoTiTa2O8 by molten salt method for LTCC application

Synthesis, phase structure and dielectric properties of CoTiTa2O8 by molten salt method for LTCC application

Enhanced performance of Mo-doped TiNb2O7 anode material for lithium-ion batteries via KOH sub-molten salt synthesis

TiNb2O7 (TNO) as an electrode material for lithium-ion batteries (LIBs) has relatively high safety and high theoretical capacity, making it an excellent alternative to the graphite anode. Nevertheless, its practical application is limited by its sluggish ionic and electronic conductivity. To address this challenge, Mo-doped TiNb2O7 (Mo-TNO) is synthesized via a KOH sub-molten salt method followed by calcining process. In this method, the low-cost raw materials are co-dissolved and then coprecipitated to achieve homogeneous mixing and particle refinement, further ensuring the uniformity of calcined products. The doping of Mo6+ facilitates cation mixing and charge compensation, leading to reduced charge transfer resistance and enhanced electronic conductivity. The reversible specific capacity of Mo-TNO after 300 cycles is maintained at 148 mA h g−1 with a high capacity-retention of 80 % at 5C. Even at 30C, it still exhibits a better capacity of 100.2 mA h g−1, much higher than the pristine TNO (58.9 mA h g−1). Furthermore, the full battery employing Mo-TNO as an anode and commercial LiNi0.6Co0.2Mn0.2O2 (NCM) as a cathode exhibits superior electrochemical performances with promising application prospect. These findings underscore the significant potential of Mo-TNO as a high-rate and long-life anode material for LIBs.

Improvement and Validation of an Analytical Method for Propionic Acid and Salts (Sodium, Calcium, and Potassium) in Foods

Improvement and Validation of an Analytical Method for Propionic Acid and Salts (Sodium, Calcium, and Potassium) in Foods

Contribution of salting on the safety assurance of artisanal “Bagaces” cheese, a Mesoamerican firm dry-salted unripe cheese

The efficacy of salting to ensure the safety of “Bagaces” cheese was assessed. Six producers with different processing practices were visited to develop a standard processing protocol for “Bagaces” cheese making. The effect of two different salting methods (brine or dry direct salting) and two cheese geometries (block or cubes) were assessed on product pH, water activity (Aw) and salt content. Both cheese geometry and salting method significantly influence the salting kinetics (p = 0.0027 and p = 0.0187, respectively), yet based on the physicochemical properties measured and its influence on pathogens growth based on previous studies, salting may not guarantee the safety of the final product as a critical measure of control since the growth of reference pathogens is likely to occur. Therefore, milk pasteurization, refrigeration during cheese storage and distribution, and strict application of good manufacturing practices are required for the safety assurance of this artisanal Mesoamerican cheese.

Sintesis Lapis Empat Fasa Aurivillius Ca1-xBaxBi3,5La0,5Ti4O15 Dengan Metode Lelehan Garam

The four-layer Aurivillius phase Ca1-xBaxBi3.5La0.5Ti4O15 (x = 0.2, 0.4, 0.6, 0.8, and 1) has been synthesized by molten salt method. The effect of varying x on the structure, morphology, and dielectric properties was studied. X-ray diffraction (XRD) and Le Bail refinement revealed that the compounds with the composition x = 0, 0.2, and 0.4 were single-phase product with orthorhombic A21am structure, whereas for higher x value (composition of Ba doped), a Ba2TiO4 impurity is found in products. Changes in unit cell volume were investigated, and the size increased with larger x. The substitution of larger Ba2+ ions resulted in a shorter Ti-O bond, shifting vibration mode to higher wave number that showed in FTIR spectra. SEM images show anisotropic plate-like grain with distributed particle sizes at 1.9 – 3.1μm. The dielectric constant values decrease with increasing x, otherwise the dielectric loss values increase for x = 0 and 0.2, however decrease for x = 0.4. The resulting Aurivillius compound has potential for applications in ferroelectric and piezoelectric devices.

Structural and dielectric properties of Eu3+,B3+ co-doped CoNb2O6 ceramic

The boron co-doped CoNb2O6:xEu3+, yB3+ (x=1, 3, 6, 9, 12 mol%, y=10 mol%) ceramics were obtained by the molten salt method, which has advantageous properties such as short reaction time, low sintering temperature, improved homogeneity, and crystallinity. The ceramic samples were examined by structural and dielectric analyses. In X-ray diffractions, the orthorhombic columbite type CoNb2O6 structure was obtained, and also a minor EuNbO4 phase was detected with increasing Eu3+ doping concentrations. Additionally, increasing Eu3+ concentration led to a slight increase in crystallite size, and two theta peak shifts occurred towards higher angles associated with shrinkage in the lattice or reduction in the lattice constant. In SEM examinations, a slight increase was observed in grain sizes from 1 to 9 mol% Eu3+ in the range of 1-30 m, while some decrease occurred in grain sizes at 12 mol%, and there was an evident increase in plate-shaped and elongated grains. The dielectric constant (ε') of the ceramic samples increased with increasing Eu3+ concentration and reached approximately 35 and 0.24 at 20 Hz for 9 mol% Eu3+, respectively. The increase in dielectric loss with increasing Eu3+ was associated with an increase in ionic conductivity, in which Eu3+ substitution does not suppress oxygen vacancies or make them more ordered.