Chemical Stability Research Articles

A new luminescent material based on bismuth(III): Synthesis, structural characterization, DFT calculations, Hirshfeld surface, thermal behavior, vibrational and optical properties

Bismuth-halide-based hybrid materials are desirable in luminescent applications due to low toxicity and chemical stability. (C8H12N)4Bi2Cl10, was elaborated by the slow evaporation technique at room temperature. Single-crystal X-ray diffraction analysis indicates that the compound belongs to the monoclinic crystal system with the centrosymmetric space group P21/c. The formula unit comprises four protonated organic cations (C8H12N)4+, one [Bi2Cl10]4− dimer. The organic layers are inserted between the inorganic ones and connected with N-H…Cl and C-H…Cl hydrogen bonds to build a three dimensional network. The infrared IR and Raman studies which were recorded at room temperature in the 500–4000 cm−1 and 50–4000 cm−1 frequency regions, respectively, confirmed the existence of vibrational modes that correspond to the organic and inorganic groups. The optimized molecular structure and vibrational frequencies were calculated by the Density Functional Theory (DFT) method using the B3LYP level employing level employing a LANL2DZbasis set. It shows a good agreement between the calculated and the experimental vibrational frequencies. Hirshfeld surface analysis of close intermolecular interactions in this compound enables the identification and examination of molecular shapes. The crystal exhibits thermal stability up to 160 °C using the Thermogravimetric analysis TGA. The optical properties were characterized experimentally by UV–visible absorption studies and photoluminescence measurements. The Photoluminescence spectrum shows a green luminescence peak which is attributed to excitonic emissions within the chlorobismuthate octahedron. HOMO-LUMO orbital energies were studied by using DFT calculations.

Elucidating the effect of different divalent metals (Mn, Co, Cu, and Zn) on optical, photocatalytic degradation, reusability and ionizing radiation attenuation properties of lanthanum ferrite nanoparticles

Ferrite nanoparticles are promising materials in various fields due to their unique magnetic and chemical stability, remarkable utilization in photocatalytic degradation, and ionizing radiation attenuation properties. So, in the present work, M0.45La0.1Fe1.45O4 (M = Zn, Mn, Cu, and Co) ferrite nanoparticles (MLF nanoparticles) have been explored as a means for improving optical, photocatalytic degradation, reusability, and ionizing radiation attenuation properties. The obtained optical band gaps are 2.44 ± 0.01 eV, 2.20 ± 0.01 eV, 1.93 ± 0.01 eV and 1.70 ± 0.01 eV for the CuLF, ZnLF, CoLF, and MnLF, respectively. The optical band gaps of all the MLF nanoparticles lie within the visible range, indicating their potential as photocatalysts under visible light. The MnLF nanoferrite shows the best degrading efficiency at 97.29 % for methylene blue dye with outstanding stability and enhanced recyclability. In addition, according to the gamma-ray attenuation characteristics of the MLF nanoparticles, the sample ZnLF shows a promising ability for radiation attenuation due to its higher mass attenuation coefficient in comparison with the mass attenuation coefficient of the other MLF nanoparticles. Also, the ZnLF sample has the highest effective atomic number, and this is due to the high atomic number of Zn element in comparison with the other MLF nanoparticles.

“Nano-fishnet” shaped PCL/PU-based composite membrane as superhydrophobic oil-water separator

Nowadays, there is a growing interest in the development of eco-friendly oil-water separation membranes with selective wettability. However, the poor mechanical property often limits their applications. Herein an environmentally friendly polycaprolactone/polyurethane-based composite membrane (PCL/PU4@PDA@SA) was prepared by coaxial electrospinning. The PCL/PU4@PDA@SA was ingeniously designed with PCL distributed in fibers and PU produced in the nodule of “nano-fishnet”. The PCL fibers bonded by PU had good mechanical properties and excellent stability. The “nano-fishnet” combining SA with low surface energy endowed the superhydrophobicity of PCL/PU4@PDA@SA surface. Due to its multi-stage pore structure, the PCL/PU4@PDA@SA demonstrated superior efficiency in oil-water separation. Even after 10 cycles, the separation efficiency was still higher than 99.54%. Additionally, the PCL/PU4@PDA@SA membrane had good self-cleaning performance, friction durability, and chemical stability. This research highlighted a way to design a sustainable separator with controllable composition distribution and morphology.

Synthesis and characterization of fluorenone derivatives with electrical properties explored using density functional theory (DFT)

This study provides thorough computational and experimental assessments of four types of novel synthesized thiosemicarbazones. The compounds were effectively synthesized using a condensation reaction between thiosemicarbazide and fluorenone, producing a remarkable range of 70–88%. Additional chemical structures were examined utilizing spectroscopic methods, including Fourier-transform infrared spectroscopy (FTIR), NMR spectroscopy, and ultraviolet-visible spectroscopy. The computational analyses utilized DFT using the M06/6-311G (d, p) technique. The electrical characteristics, including the stability of orbitals via energy exchange between a donor and acceptor, can be evaluated by natural bond orbital (NBO) analysis. The nonlinear optical (NLO) properties were analyzed to detect any prohibited energy gaps. FTIR and UV-visible data were computed using the identical M06/6–311G (d, p) level of theory. The NBO test has confirmed the occurrence of charge separation due to the efficient transfer of electrons from the donor to the acceptor unit over the π bridge. The molecular chemical softness and hardness are dependable indications of a molecule’s chemical stability. A significant magnitude of the absolute value of polarizability and hyper-polarizability indicates considerable dispersion of electric charge. The outcomes derived from Density Functional Theory (DFT) generally align well with experimental findings.

Silane-free superhydrophobic coatings from ball-milled nanosand using eco-friendly polymeric modifiers

A simple immersion method is proposed to develop durable superhydrophobic cotton fabric from low-cost, fluorine and silane-free eco-friendly materials, to address the growing environmental concerns led by hazardous surface modifiers. Herein, silica sand nanoparticles (SS NPs) were synthesized by mechanical ball-milling approach, from a least reported silica abundant natural source, Cherthala sand. Cherthala a small town in the Alappuzha district of Kerala is noted for its high quality sand with 96.5% silica. The synthesis of SS NPs was optimized based on ball-to-powder weight ratio (BPR) and milling time using Central Composite Design of response surface methodology. Minimum crystallite size (∼26 nm) and maximum turbidity (355 NTU) were obtained for the trial loaded with 20:1 BPR and processed for 10 hours. In a traditional nano-coating approach, the milled SS NP was employed as the roughness-enhancer along with polymeric binder for adhesion; silicone oil and stearic acid to lower the surface energy. The standardized coating mixture exhibited maximum water contact angle 158.9 ± 7.6°, long-term water repellency, chemical stability after 12 hours standing in acidic and alkaline pH and more than five detergent washing cycles. The coated fabrics were resilient to O2-plasma, UV-irradiation and adhesive peel test. The study also presented the practical scope of the developed eco-friendly coatings for oil-water separation and in wearable smart textiles. Thus, the present work offers a scalable sustainable route to develop silica NP-based functional textiles with same comfort, touch-proof, and breathability.

FORMING HYDRATE COMPOUNDS SYSTEM 3СaO·Al2O3·3CaSO4·32H2O DURING THE ALUMINATE CEMENT MINERALS HYDRATION

Problem statement. The use of modifying additives and research of their influence on the thermodynamic and hydrodynamic stability of the solidification structure of 3СaOAl2O3·3CaSO432H2O ettringite will lead to an increase in water resistance, improvement of technological factors, which in turn will contribute to the expansion of the scope of application of composites based on such additives. By means of adjusting the water-solid ratio, you can control properties of the initial composite: you can obtain the necessary structure and water resistance. Research of the effect caused by additives on the composites of the CaO–Al2O3–SO3–H2O system and the subsequent development of their compositions will provide an opportunity to control the hydration processes, form highly basic ettringite with the amount of chemically bound water in it reaching 46 %. Purpose of the article – to conduct a research on modification of the ettringite phase aimed at increasing its stability. Conclusions. Stabilization of ettringite composite of optimal composition (70 % of alumina cement and 30 % of gypsum) was determined based on the results of toponymic reactions of transition of the system from the macro-system to the micro- and nanosystem when changing time, by conducting X-ray phase analysis after 3, 7, 14 and 28 days. According to the selected research methodology, semi-aqueous gypsum was modified with alumina cement. Experimentally determined was optimal amount of the modifier (70 % of alumina cement) which is necessary to increase physical and mechanical properties, as well as to form necessary mineralogical composition of the modified binder. During hydration of modified binders based on alumina cement and gypsum, formation of ettringite occurs, which makes it possible to form the necessary structure and basic physical and mechanical properties.

Chiral Supramolecular Proton Conductors: Harnessing Highly Charged Zirconium-Amino Acid Oxo-Clusters.

Incorporation of amino acid capping molecules (alanine (Ala), methionine (Met), phenylalanine (Phe), tryptophan (Trp), tyrosine (Tyr), and valine (Val)) in their zwitterionic form into archetypal [Zr6(μ3-O)4(μ3-OH)4]12+ clusters creates supramolecular frameworks in which the assembly of these highly charged discrete units with chloride counterions provides a unique combination of porosity, chirality, and proton conductivity. The supramolecular frameworks assembled from these cluster entities (i.e., ZrAla, ZrMet, ZrPhe, ZrTrp, ZrTyr, and ZrVal) are based on the counterbalancing of the cationic hexanuclear entities by chloride anions. The resulting structures provide porous structures (except ZrVal) with variability of chemical and structural stability based on their supramolecular interactions. Among these compounds, ZrPhe and ZrVal remain stable due to the presence of a double chelation-like interaction involving four hydrogen bonds formed between a chloride anion, two ammonium groups, and two coordinated water molecules from two adjacent hexanuclear units. The presence of multiple acidic proton positions and strong hydrogen-bond donor/acceptor groups on the water channels gives rise to easy proton conduction pathways within the structures. In fact, ZrPhe and ZrVal, together with ZrTyr, exhibit high proton conductivity values with varying dependencies on the atmospheric humidity. Finally, the correlation between proton conduction and porosity is discussed.

Pyrroloquinoline quinone exhibiting peroxidase-mimicking property for colorimetric assays

BackgroundSmall molecule mimics offer the advantages of easy preparation, good thermodynamic stability, and reproducible catalytic activity. However, most of the reported organic artificial mimics face challenges including low catalytic activity, oxidative self-destruction, and auto-aggregation into inactive dimers. Therefore, novel organic mimics with high catalytic activity as well as good thermal and environmental stability are highly desirable. ResultsWe found that pyrroloquinoline quinone (PQQ), a nutritionally important growth factor, displayed significant peroxidase-like activity to catalyze the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into blue oxidized TMB (oxTMB) by H2O2. Its catalytic activity surpassed that of other organic small molecules reported previously, including fluorescein derivatives and adenosine/guanosine triphosphate. Based on the reduction of oxTMB by the enzymatically generated ascorbic acid (AA), the PQQ/TMB-based system was used to monitor alkaline phosphatase (ALP) activity with ascorbic acid 2−phosphate (AAP) as the substrate. This sensing system allowed for the determination of ALP with a detection limit of 1 mU/mL. Furthermore, we discovered that PQQ can coordinate with Cu2+ to form metal-organic nanoparticles. The building blocks of two active cofactors endowed the nanoparticles with impressive functionalities for biocatalytic applications. With Cu-PQQ nanoparticles as signal labels, colorimetric immunoassays of prostate specific antigen (PSA) were achieved with a lowest detectable concentration down to 0.1 pg/mL. SignificanceThis work is valuable for the design of novel biosensors by utilizing PQQ as an artificial enzyme because of its high catalytic activity, good stability, ease of storage, and simple chemical structure.

Chiral recognition of amino acids through homochiral metallacycle [ZnCl2L]2.

Chiral recognition holds tremendous significance in both life science and chemistry. The ability to differentiate between enantiomers is crucial because one enantiomer typically holds greater biological relevance while its counterpart is often not only unnecessary but also potentially harmful. In this regard, homochiral metallacycle [ZnCl2L]2 is used in this study to understand and differentiate between the R and S enantiomers of amino acids (alanine, proline, serine, and valine). The electronic, geometric, and thermodynamic stabilities of the amino acid enantiomers inside the metallacycle are determined through various analyses. The greater interaction energy (Eint) is obtained for the ser@metallacycle complexes i.e., -33.03 and -30.75 kcal mol-1, respectively for the S and R enantiomers. The highest chiral discrimination energy of 3.11 kcal mol-1 is achieved for ala@metallacycle complexes. Regarding the electronic properties, the frontier molecular orbital (FMO) analysis indicates that the energy gap decreases after complexation, which is confirmed through density of states (DOS) analysis. Moreover, natural bond orbital (NBO) analysis determines the amount and direction of charge transfer i.e., from metallacycle towards amino acids. The maximum NBO charge transfer is observed for S-pro@metallacycle complex i.e., -0.291 |e|. Electron density difference (EDD) analysis further proves the direction of charge transfer. Noncovalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses demonstrate that the noncovalent interactions present between the host and guest are the weak van der Waals forces and hydrogen bonding. The results of NCI and QTAIM analyses for all the complexes are in alignment with those of the interaction energy (Eint) and chiral discrimination energy (Echir) analyses, i.e., significantly greater non-bonding interactions are observed for the complexes with greater Echir, i.e., for ala@metallacycle. Overall, our analyses demonstrate the excellent chiral discrimination ability of metallacycle towards chiral molecules, i.e., for enantiomers of amino acids through host-guest supramolecular chemistry.

Shielding Fluoride Ion Basicity through Diurea Coordination for Nonaqueous Fluoride Shuttle Batteries.

The strong basicity of fluoride ions leads to detrimental nucleophilic attack on organic components in the electrolytes, such as β-hydrogen elimination reactions with organic cations and solvents, converting "naked" F- into corrosive and unstable bifluoride (HF2-) ions. These reactions significantly constrain the choice of suitable solvents and salts to develop electro(chemical) stable fluoride ion electrolytes. In this work, we replaced the triple water ligands typically present in industrialorganic fluoride salts with dual 1,3-diphenylurea (DPU) coordination via hydrogen bonding interaction. This modification successfully suppressed the Lewis basicity of fluoride ions, providing long-term chemical stability (over 1000 hours) acrossa wide range of aprotic solvents, a broadened electrochemical stability window (-2.5 ~ 0.9 V vs. Ag+/Ag) and high ionic conductivity (1.7 mS cm-1) at room temperature. Additionally, the weaker hydrogen bonding in F--DPU coordination, compared to the conventional boron-based anion acceptor (AA) strategy that relies on intensive Lewis acid-base interactions, facilitates faster (de)fluorination kineticsat the electrode. The proposed room temperature fluoride ion batteries sustain improved electrochemical performance by pairing with the Pb-PbF2 anode and BiF3 or Ag cathode.

Preparation of highly hydrophobic melamine sponge for oil-water separation through copolymerization deposition

The frequent occurrence of petrochemical spills and the uncontrolled discharge of oily industrial wastewater have caused serious water pollution problems. In this study, a novel modified melamine sponge, namely U-HDA@MS, was prepared by a simple, environmentally friendly, and cost-effective method using urushiol, a natural polymer, as the major modifier. The reaction mechanism of the precipitation copolymerization of urushiol and 1,6-hexamethylenediamine (HDA) and the in-situ deposition of the copolymer were investigated by chemical structure and microscopic morphology analyses. It was found that the self-polymerization of urushiol and the copolymerization of urushiol and HDA produced ethanol-insoluble copolymers. Subsequently, the deposition of the copolymers formed a coating with a micro/nano hierarchical structure and a large number of hydrophobic groups on the sponge skeleton, making U-HDA@MS highly hydrophobic and oleophilic. The water contact angle reached 145° without silanization modification, and the absorption capacity for carbon tetrachloride was up to 122 g/g. The outstanding chemical stability of the deposited coating made U-HDA@MS durable in harsh conditions. It maintained stable hydrophobicity and high absorption capacity over a wide pH range. Absorption-squeezing and continuous absorption experiments verified the outstanding reusability and oil-water selectivity of U-HDA@MS. This demonstrates its promising application in oil-water separation and petrochemical spill cleanup.

Stoichiometry-Regulated Synthesis of Three Adenine-Based Coordination Polymers for Catalytic Excellence through the Synergistic Amalgamation of Coordinative Unsaturation and Lewis Basic Sites.

Nucleobase adenine is a promising candidate for synthesizing fascinating coordination polymers (CPs) due to the presence of five potential metal-ion binding centers. In recent years, CPs have emerged as promising Lewis acid-base centers containing heterogeneous catalysts for a wide range of organic transformations. However, the crucial role of stoichiometric regulations of the starting materials and their consequential impact on catalytic performance are rarely studied. Herein, we have synthesized three adenine (Ad)-based cadmium CPs with 5-nitro isophthalic acid (H2NIPA) by a mixed linker approach by tuning the substrate's stoichiometric proportion. The single-crystal X-ray diffraction analysis of the synthesized CPs, SSICG-11, [Cd(Ad)(NIPA)(H2O)]·H2O; SSICG-12, [Cd(Ad)2(NIPA)(H2O)]; and SSICG-13, [Cd4(Ad)(NIPA)3]·H2O·DMF, reveals that these three compounds exhibit distinct asymmetric units, each reflecting varying precursor proportions. Due to their high chemical stability and the presence of both Lewis acidic-basic sites, SSICG-11-13 were employed as heterogeneous catalysts for Hantzsch and Strecker reactions. However, SSICG-12 is more efficient due to its capacity to form an open metal sites (OMSs) and the presence of a higher number of adenine moieties. Overall, this study demonstrated the stoichiometrically controlled synthesis of adenine-based CPs and dissected their efficiency as a heterogeneous catalyst by correlating their structures and compositions.

Structural properties, thermodynamic stability and reaction pathways for solid-state synthesis of Bi2WO6 polymorphs.

This study presents a density functional theory (DFT) investigation into the structural, electronic, and optical properties, thermodynamic stability, phase competition, and reaction pathways of Bi2WO6, a notable compound within the Aurivillius family of oxides. We examine three distinct polymorphs of Bi2WO6: the low-temperature orthorhombic phase (P1), the intermediate-temperature orthorhombic phase (P2), and the high-temperature monoclinic phase (P3). Electronic structure analysis indicates band gaps of 2.339 eV (P1), 2.312 eV (P2), and 2.128 eV (P3), with the valence band primarily composed of O 2p states and the conduction band of Bi 6p and W 5d states. Optical properties, including the dielectric function and absorption spectra, show distinct behaviors for each phase, particularly P3. Elastic and phonon property analyses confirm the mechanical and dynamical stability of all three phases, with the P1 phase exhibiting the highest bulk modulus and stiffness among the polymorphs. Our effective mass calculations suggest that the P3 phase may have better charge carrier mobility compared to the P1 and P2 phases. Structural optimizations reveal marginal differences in total energy among these phases, suggesting their potential coexistence or easy phase transitions under varying conditions. Detailed Gibbs free energy calculations confirm that the P1 phase is the most stable at low temperatures, in agreement with experimental data in the literature. We also construct a chemical reaction network to explore feasible reaction pathways for the solid-state synthesis of Bi2WO6 from Bi2O3 and WO3 precursors, identifying several low-cost reaction pathways, including both direct and multi-step routes involving intermediates such as Bi14WO24 and Bi2W2O9.

Thermodynamic characteristics of nitrifiers reveal the potential NOB inhibition strategies at low temperatures

Nitrification is a highly temperature-sensitive biological process, yet relatively little research has explored thermodynamic characteristics of enzyme-catalyzed nitrification processes in wastewater treatment systems. In this study, a variety of thermodynamic models were employed to evaluate thermodynamic characteristics of four activated sludge samples cultivated under various temperatures (10, 15, and 20 °C) and ammonia nitrogen concentration (40 mg/L and 300 mg/L). Results revealed a higher maximum temperature (Tmax) for ammonia oxidizing bacteria (AOB) compared to nitrite oxidizing bacteria (NOB), suggesting the robust resistance to high temperatures of AOB. Conversely, the lower minimum temperature (Tmin) of NOB indicated its stronger tolerance to low temperatures. Notably, both low temperatures and high-ammonia nitrogen concentrations are conducive to the competition of Nitrotoga over Nitrospira, resulting in Nitrotoga emerging as the dominant NOB within 10∼15 °C. Moreover, heat capacity (ΔCpǂ) of enzymes exhibited a similar trend across all samples, i.e. HAO > AMO > NOR, indicating that HAO exhibited the strongest thermodynamic stability, followed by AMO, and NOR has the worst thermodynamic stability. Additionally, the difference in optimal temperature (Topt) between dominant AOB-Nitrosomonas and dominant NOB-Nitrotoga cultivated at high nitrogen concentration and low temperature could reach up to +8.13 °C, enabling selective inactivation of NOR through thermal treatment at Topt,AOB ∼ Topt,NOB. However, despite insignificant differences in Topt,AOB and Topt,NOB under low-temperature and low-ammonia nitrogen concentration, the smaller the difference between Tmax and Top (Tmax-Topt) of NOB and smaller D-value of NOR made NOB more susceptible to inhibition than AOB. However, the presence of low-abundance Nitrospira renders thermal treatment alone inadequate for complete NOB inhibition, combing it with other strategies is necessary for effective inhibition. Therefore, the fundamental differences in thermodynamic characteristics of AOB and NOB determine the potential of NOB inhibition strategies at low temperatures.

Fabrication of MXene-TiO2 nanotube composite and their electrochemical study in acidic and alkaline medium

MXenes, a novel class of two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, have emerged as promising electrocatalysts for the hydrogen evolution reaction (HER) due to their remarkable electrical conductivity, exceptional structural and chemical stability, and large active surface area. In this study, we synthesized a 1D/2D Ti3C2 MXene-TiO2 nanotube (TNT) composite via electrostatic self-assembly method. Field emission scanning electron microscopy (FE-SEM) confirmed the distinctive accordion-like, multilayered morphology of Ti3C2Tx MXene, while X-ray diffraction (XRD) provided the crystalline phase of the composite. High-resolution transmission electron microscopy (HR-TEM) revealed an average particle size of 38.41 nm for the MXene-TNT nanocomposite. Additionally, X-ray photoelectron spectroscopy (XPS) confirmed the composite composition, highlighting the synergistic integration of MXene and TiO2 nanotube that enhances electrical interactions and contributes to superior catalytic performance. Electrochemical performance was assessed using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) in both acidic and alkaline media. Among the composites, the MXene-TNT (1:10) loading demonstrated a low Tafel slope of 65 mV/dec in acidic media, indicative of enhanced mass transfer properties. In alkaline media, the MXene-TNT (1:5) composite exhibited a Tafel slope of 160 mV/dec for HER, with kinetic performance proving more favorable in the acidic environment. Additionally, the composite displayed a Tafel slope of 149 mV/dec for the oxygen evolution reaction (OER) in acidic media. This study demonstrates a feasible approach for developing high-performance, cost-effective electrocatalytic materials for efficient hydrogen production, utilizing MXene as a co-catalyst.

Thymoquinone loaded nanoemulgel in streptozotocin induced diabetic wound.

Aim: To treat diabetic wound healing with a novel Thymoquinone (TQ) loaded nanoformulation by using combination of essentials oils.Methods: TQ nanoemulsion (NE) was developed with seabuckthorn & lavender essential oils by phase inversion method and mixture design. Further, DIAGEL is obtained by incorporating NE into 1% carbopol®934. Furthermore, particle size, polydispersity index, thermodynamic stability studies, rheology, spreadability, drug content, in-vitro drug release, ex-vivo permeation, anti-oxidant assay, antimicrobial studies, angioirritance, HAT-CAM assay, in-vitro and in-vivo studies were determined.Results: NE has a particle size of 17.79±0.61nm, 0.206±0.012 PDI & found to be thermodynamically stable. DIAGEL exhibited pseudoplastic behavior, sustained drug release, better permeation of TQ and a drug content of 98.54±0.08%. DIAGEL stored for 6months at room temperature and 2-8°C showed no degradation. Further, an improved angiogenesis, absence of angio-irritancy, remarkable antioxidant and antimicrobial activities against Candida albicans & S. aureus were observed. Cytotoxicity analysis revealed nearly 2.28 -folds higherIC50 value than drug solution. Furthermore, inflammatory mediators were reduced in DIAGEL treated animal groups. The histopathological studies confirmed skin healing with regeneration and granulation of tissue.Conclusion: The novel formulation has strong anti-inflammatory, angiogenesis, antioxidant and appreciable diabetic wound healing properties.

Homeostatic Microfiber-Composed Synthetic Leathers with Chemical Robustness and Undercooling Self-Regulation.

Homeostatic microfiber leathers with temperature self-regulation promise broad applications, ranging from the apparel and automotive interior industries to the home furnishing and healthcare industries. Temperature self-regulation is achieved by phase-change materials containing microcapsules introduced within the leathers. The introduction of phase change microcapsules (PCMs) into microfiber leather faces two formidable challenges: (1) the shell of microcapsules must remain chemically stable against alkalis and organic solvents; (2) PCMs possess the ability to reduce supercooling during which latent heat is released, allowing for the precise and controllable release of latent heat. Here we present a high-performance homeostatic microfiber-composed synthetic leather containing PCMs that can address these two challenges, which not only demonstrate exceptional chemical robustness under alkaline conditions but also offer efficient and precise control over temperature fluctuation and latent heat release by reducing supercooling. Titanium carbide (TiC) known for its high thermal conductivity and alkali resistance has been selected as the shell material for the microcapsules, which can effectively resolve chemical stability issues. Meanwhile, the high thermal conductivity of TiC can be leveraged to enhance heterogeneous nucleation, thus narrowing the temperature range for latent heat release. The resultant microfiber leather shows outstanding capabilities for adjustable thermal energy storage. Our studies offer an effective approach to create homeostatic microfiber-composed synthetic leathers with chemical robustness and undercooling self-regulation, which would be useful in the fields of the textile, biomedical, and healthcare industries.

Tailoring hydrogen diffusion pathways in Mg-Ni alloys through Gd addition: A combined experimental and computational study

Magnesium-based alloys represent a promising avenue for solid-state hydrogen storage, yet their practical implementation is impeded by sluggish kinetics and thermodynamic stability. This study presents a systematic investigation into the effects of gadolinium (Gd) and nickel (Ni) content on the microstructure and hydrogen storage properties of Mg-Ni-Gd alloys. Through advanced characterization techniques and density functional theory calculations, we elucidate that Gd preferentially occupies sites in the Mg2Ni phase rather than the Mg matrix, facilitating hydrogen diffusion. The Mg-7.8Ni-2.2Gd alloy demonstrates superior performance, absorbing 5.8 wt% hydrogen at 300 °C, compared to 5.3 wt% for Mg-10Ni under identical conditions. Remarkably, this composition exhibits excellent low-temperature kinetics, absorbing 4.5 wt% hydrogen within 30 min at 120 °C and maintaining 99 % capacity retention after 128 cycles. Post-initial hydrogenation, Gd accumulates at Mg2Ni surfaces, amplifying its role as a “hydrogen pump”. Kinetic analysis using the Chou model for absorption and the Johnson-Mehl-Avrami-Kolmogorov model for desorption provides quantitative insights into the improved hydrogen storage mechanisms. Our computational studies corroborate these experimental findings, revealing that Gd doping in Mg2Ni substantially improves the hydrogen absorption ability, and surface penetration barrier of H atom deeply decreased. This work not only advances our understanding of the complex interplay between composition, microstructure, and hydrogen storage properties in Mg-based alloys but also establishes design principles for high-performance hydrogen storage materials.

Advancements in CdTe Thin‐Film Solar Cells: Is Doping an Effective Strategy for Performance Enhancement?

Cadmium telluride (CdTe) thin‐film solar cells that are introduced in 1970s have emerged as one of the forefront materials of the second generation‐based solar cells. They are preferred as an ideal candidate for the fabrication of reliable and economical photovoltaic systems owing to high optical absorption coefficient, nearly optimum bandgap for ensuring maximum conversion efficiency and chemical stability. The major challenges associated with these solar cells are low concentration of carriers, which limits the photovoltaic parameters notably the open‐circuit voltage and fill factor as well as short life time of absorber minority carriers. This article explores the pivotal role of doping in enhancing the electrical properties and life time of minority carriers of CdTe solar cells through extensive literature study of the complexity of mechanisms and output parameters achieved in various reported works. Doping has been systematically reviewed with emphasis on types of doping, classification of dopants into group I and group V dopants along with a concise summary of different dopants. This comprehensive review not only evaluates the recent advancements of CdTe solar cells but also addresses these issues and provides future perspectives and paves way for development of improved stable and highly efficient cells.

First principle study of physical aspects and hydrogen storage capacity of magnesium-based double perovskite hydrides Mg2XH6 (X = Cr, Mn)

Hydrogen's potential as a clean energy source has propelled hydrogen storage into a pivotal realm of contemporary research. Cutting-edge double perovskite compounds have become a central focus for exploring hydrogen storage applications. The aim is to scrutinize their structural, mechanical, electronic, magnetic, thermoelectric, and hydrogen storage properties. The negative value of enthalpy of formation and approaching value of tolerance factor confirm the thermodynamic and structural stability of studied compositions, leading to the calculation of ground state lattice parameters. The high value of Curie temperature (310 K), particularly for Cr-based composition, exhibits the viable application of this composition at room temperature. Metallic behavior in the spin-up channel and semiconducting nature in the spin-down channel are witnessed in the band structure that ascertains the half-metallic behavior of both compositions, ensuring 100% spin polarization, an essential feature for spintronic devices. Furthermore, employing the BoltzTraP code to analyze thermoelectric characteristics with heightened Seebeck coefficients and reduced thermal conductivity reveals their suitability for thermoelectric devices. Moreover, investigation into the hydrogen storage characteristics of Mg2XH6 (X = Cr, Mn) exhibits notable hydrogen storage capacities of 5.60 wt% for Mg2CrH6 and 5.51 wt % for Mg2MnH6. This study marks the pioneering examination of Mg2XH6 (X = Cr, Mn) double perovskite-type hydrides, promising significant contributions to future research endeavours in hydrogen storage applications.