Entropic Effects Research Articles

Theory of Faults (ToF): Numerical Quality Management in Complex Systems

The purpose of this manuscript is to provide general system theory concepts and practical tools for management under complexity. Built environments and infrastructure are produced, operated, and maintained by information systems; they are also integral components of information systems themselves. These systems are self-organized and teleonomic. The complexity inherent in built environments and infrastructure systems poses a challenge to research, hindering forecasting and the implementation of managerial tools. The use of faults, which are complex systems’ responses to penetrating risk, provide us with databases of and windows into complex systems. This manuscript presents an explicatory theory (ToF), develops it mathematically, expands it through numerical experiments, validates it by case studies, and relates it to practice by expert contributions. A statistical analysis provides a phase parameter, descriptive statistics elucidate trending and emergent behaviors, digital signal processing expounds the effects of signals on information overload, and a directed-network analysis portray morphology, entropy, and time effects. The novelty of ToF is in the application of complexity theory to construction to produce data analysis tools and a managerial framework.

Effects of high entropy combined with Cu/Ag doping on the thermoelectric properties of Bi2Sr2Co2Oy ceramics

Effects of high entropy combined with Cu/Ag doping on the thermoelectric properties of Bi2Sr2Co2Oy ceramics

Excellent Electrochemical Performance and Air Storage Stability of Na-Ion Layered Oxide Cathodes Benefiting from Enhanced Ce-O Binding Energy.

The widespread application of layered oxides is constrained by their low electrochemical performance and complex irreversible phase transition. The high entropy oxide NaNi0.25Fe0.15Mn0.3Ti0.1Sn0.05Co0.05Li0.1O2 (HEO) is synthesized by leveraging the entropy stabilization effect, which offers a partial solution to this issue, but electrochemical performance and air stability imperative to be improved. On the high entropy oxide HEO, due to the strong bond energy of Ce-O, the introduction of Ce4+ improves the specific discharge capacity and reduces the battery gas production problem. It also improves the air stability. NaNi0.25Fe0.15Mn0.3Ti0.1Sn0.03Ce0.02Co0.05Li0.1O2 (HEO-Ce2) demonstrated a specific discharge capacity of 160 mA h g-1 at 0.1 C. The discharge-specific capacity retention rate of the material is 86%, after air exposure for 10 days. The high entropy effect and introduction of Ce4+ provide a viewpoint for a layered oxide of sodium-ion batteries.

10-Fold Increase in Hydrogen Atom Transfer Reactivity for a Series of S = 1 FeIV═O Complexes Over the S = 2 [(TQA)FeIV═O]2+ Complex via Entropic Lowering of Reaction Barriers by Secondary Sphere Cycloalkyl Substitution.

Nonheme iron enzymes utilize S = 2 iron(IV)-oxo intermediates as oxidants in biological oxygenations. In contrast, corresponding synthetic nonheme FeIV═O complexes characterized to date favor the S = 1 ground state that generally shows much poorer oxidative reactivity than their S = 2 counterparts. However, one intriguing exception found by Nam a decade ago is the S = 1 [FeIV(O)(Me3NTB)]2+ complex (Me3NTB = [tris((N-methyl-benzimidazol-2-yl)methyl)amine], 1O) with a hydrogen atom transfer (HAT) reactivity that is 70% that of the S = 2 [FeIV(O)(TQA)]2+ complex (TQA = tris(2-quinolylmethyl)amine, 3O). In our efforts to further explore this direction, we have unexpectedly uncovered a family of new S = 1 complexes with HAT reaction rates beyond the currently reported limits in the tripodal ligand family, surpassing oxidation rates found for the S = 2 [FeIV(O)(TQA)]2+ complex by as much as an order of magnitude. This is achieved simply by replacing the secondary sphere methyl groups of the Me3NTB ligand with larger cycloalkyl-CH2 (R groups in 2OR) moieties ranging from c-propylmethyl to c-hexylmethyl. These 2OR complexes show Mössbauer data at 4 K and 1H NMR spectra at 193 and 233 K that reveal S = 1 ground states, in line with DFT calculations. Nevertheless, they give rise to the most reactive synthetic nonheme oxoiron(IV) complexes found to date within the tripodal ligand family. Our DFT study indicates transition state stabilization through entropy effects, similar to enzymatic catalysis.

Cyanopyridine adducts of SiF4 and SiCl4

Abstract The formation of cyanopyridine (CN-py) adducts of silicon tetrahalides was investigated for 3- and 4-cyanopyridine in combination with SiF4 and SiCl4. Whereas bubbling of SiF4 through toluene solutions of 3-CN-py and 4-CN-py afforded white precipitates, which should possess the respective composition SiF4(CN-py)2, addition of SiCl4 did not cause any precipitation. Upon storage of the toluene solution of SiCl4 and 4-CN-py at 6 °C for several weeks, some crystals of the composition SiCl4(4-CN-py)2 ⋅ 2 (4-CN-py) ⋅ (toluene) were obtained. The use of SiCl4 as the solvent (i.e. SiCl4 in large excess) and dissolving 4-CN-py therein gave access to a crystalline adduct of the composition SiCl4(4-CN-py)2 ⋅ 2 (4-CN-py). 3-CN-py instead recrystallized from SiCl4 without forming an adduct with the silane. Computational analyses (B2T-PLYP level) of the single-point energy differences between starting materials SiX 4 (X = F, Cl) and ‘pyridine’ (‘pyridine’ = pyridine, 3-CN-py, 4-CN-py) and their adducts SiX 4(‘pyridine’)2 revealed the tendencies toward adduct formation to decrease in the order SiF4 > SiCl4 as well as pyridine >> 4-CN-py > 3-CN-py. For SiCl4 with 4- and 3-CN-py, the energy of adduct formation (−7.0 and −5.7 kcal mol−1, respectively) is easily compensated by entropy effects at room temperature. Whereas the former explains as to why cyanopyridines and SiCl4 may co-exist without noticeable adduct formation, the crystal structures of the adducts SiCl4(4-CN-py)2 ⋅ 2 (4-CN-py) ⋅ (toluene) and SiCl4(4-CN-py)2 ⋅ 2 (4-CN-py) reveal the additional stabilization of these solids by co-crystallization with 4-cyanopyridine, which eventually enabled the isolation of the SiCl4(4-CN-py)2 moiety in a solid. Partial decomposition (hydrolysis) during attempts of recrystallization of SiF4(4-CN-py)2 and SiF4(3-CN-py)2 afforded crystals of the ionic compounds [4-CN-PyH]+[SiF5(4-CN-py)]– and [3-CN-PyH]+ 2[SiF6]2–, respectively.

Solvent Effects and Internal Functions Control Molecular Recognition of Neutral Substrates in Functionalized Self-Assembled Cages.

A suite of internally functionalized Fe4L6 cage complexes has been synthesized with lipophilic end groups to allow dissolution in varied solvent mixtures, and the scope of their molecular recognition of a series of neutral, nonpolar guests has been analyzed. The lipophilic end groups confer cage solubility in solvents with a wide range of polarities, from hexafluoroisopropanol (HFIP) to tetrahydrofuran, and the hosts show micromolar affinities for neutral guests, despite having no flat panels enclosing the cavity. These hosts allow interrogation of the effects of an internal functional group on guest binding properties, as well as solvent-based driving forces for recognition. Introducing polar effects to the interior of the cavity enhances guest binding affinity in nonpolar solvents; adding space-filling aliphatic groups reduces affinity in all cases. While high dielectric solvents such as acetonitrile strongly favor guest binding, "low dielectric, high polarity" solvents such as HFIP strongly occupy the cavity and prevent guest recognition. Analysis of the cage optical transitions shows that the guests interact with the central ligand cores and reside in close proximity to the internal functions. These results have implications for supramolecular catalysis: balancing directed host:guest interactions (e.g., H-bonds) with entropic effects from solvent displacement is essential for reactions in these (and related) biomimetic hosts.

Microstructural design opportunities and phase stability in the spray-formed AlCoCr0.75Cu0.5FeNi high entropy alloy

Designing a microstructure with controlled morphology is one of the determining factors for the optimum performance of a material. High entropy alloys (HEAs) have gained significant attention due to their enhanced mechanical and functional properties compared to conventional alloys, particularly based on opportunities for microstructural design. In this fast-developing field, varied thermal treatments can be applied to engineer a material as per the requirements. In the present work, we have studied the effect of thermal treatment on the microstructural modifications in the spray-formed AlCoCr0.75Cu0.5FeNi HEA. The alloy was characterized by using a light microscope, scanning electron microscope equipped with EDS detector and electron probe micro analyzer (EPMA). The elemental distribution and microstructural evolution of the alloy were studied by giving the heat treatments at different time-temperature spaces. The evolution of phases and their composition were correlated with the CALPHAD predicted property diagram and phase composition. It is observed that at a higher temperature of 1300°C, the alloy shows the simple solid solution phases to be more stable due to the high entropy effect, which brings down the Gibbs free energy of the system. The formation of the disordered BCC, FCC and their derivatives along with the sigma phase were observed in the temperature range of 600-1000°C. This work also draws attention to why understanding the microstructural evolution and solidification behaviour is important in designing the HEAs to meet the industrial promises and the role of entropy, enthalpy and slow diffusion kinetics are discussed.

High Entropy Oxide Duplex Yolk-Shell Structure with Isogenic Amorphous/Crystalline Heterophase as a Promising Anode Material for Lithium-Ion Batteries.

Achieving composition and structure regulation on high entropy materials is a big challenge but will give this kind of new materials a huge boost in energy storage. Herein, a novel high entropy oxide ((CrMnFeCoNi)3O4) duplex yolk-shell structure (DYSHEO) with isogenic amorphous/crystalline heterophase are designed and successfully prepared through a simple microthermal solvothermal reaction followed by mesothermal calcination. The microthermal solvothermal reaction results in high entropy precursor with duplex yolk-shell structure, while the mesothermal calcination (annealing temperature at 450°C) realizes the precursor transformation to (CrMnFeCoNi)3O4 (DYSHEO-450) with isogenic amorphous/crystalline heterophase structure. The high entropy effect, the duplex yolk-shell structure, and the isogenic amorphous/crystalline heterophase endow DYSHEO-450 great advantages as lithium-ion battery anode including reducing ion migration obstruction, accommodating volume expansion, and alleviating the stress. Accordingly, DYSHEO-450 exhibits high capacities of 1721 mAh g-1@0.5A g-1, and 1356 mAh g-1@1 A g-1 after 500 cycles with a capacity retention rate of 90.3%. It also shows excellent performances in practical application as anode of a coin-type full cell. This work provides new ideas and directions for the structural regulation of high-entropy materials.

The Operando Nature of Isobutene Adsorbed in Zeolite H-SSZ-13 Unraveled by Machine Learning Potentials Beyond DFT Accuracy.

Unraveling the nature of adsorbed olefins in zeolites is crucial to understand numerous zeolite-catalyzed processes. A well-grounded theoretical description critically depends on both an accurate determination of the potential energy surface (PES) and a reliable account of entropic effects at operating conditions. Herein, we propose a transfer learning approach to perform random phase approximation (RPA) quality enhanced sampling molecular dynamics simulations, thereby approaching chemical accuracy on both the determination and exploration of the PES. The proposed methodology is used to investigate isobutene adsorption in H-SSZ-13 as prototypical system to estimate the relative stability of physisorbed olefins, carbenium ions and surface alkoxide species (SAS) in Brønsted-acidic zeolites. We show that the tert-butyl carbenium ion formation is highly endothermic and no entropic stabilization is observed compared to the physisorbed complex within H-SSZ-13. Hence, its predicted concentration and lifetime are negligible, making a direct experimental observation unlikely. Yet, it remains a shallow minimum on the free energy surface over the whole considered temperature range (273-873 K), being therefore a short-lived reaction intermediate rather than a transition state species.

The Operando Nature of Isobutene Adsorbed in Zeolite H−SSZ−13 Unraveled by Machine Learning Potentials Beyond DFT Accuracy

AbstractUnraveling the nature of adsorbed olefins in zeolites is crucial to understand numerous zeolite‐catalyzed processes. A well‐grounded theoretical description critically depends on both an accurate determination of the potential energy surface (PES) and a reliable account of entropic effects at operating conditions. Herein, we propose a transfer learning approach to perform random phase approximation (RPA) quality enhanced sampling molecular dynamics simulations, thereby approaching chemical accuracy on both the determination and exploration of the PES. The proposed methodology is used to investigate isobutene adsorption in H−SSZ−13 as prototypical system to estimate the relative stability of physisorbed olefins, carbenium ions and surface alkoxide species (SAS) in Brønsted‐acidic zeolites. We show that the tert‐butyl carbenium ion formation is highly endothermic and no entropic stabilization is observed compared to the physisorbed complex within H−SSZ−13. Hence, its predicted concentration and lifetime are negligible, making a direct experimental observation unlikely. Yet, it remains a shallow minimum on the free energy surface over the whole considered temperature range (273–873 K), being therefore a short‐lived reaction intermediate rather than a transition state species.

Preparation of Low Melting Temperature Lithium-Based Binary Salts and Their Physicochemical Properties

Achieving carbon neutrality demands the development of high-performance Li-ion secondary batteries (LIB), driven by a pressing need for electric vehicles and renewable energy storage. Molten salt electrolytes offer promise for enhancing safety and performance due to their exceptional thermal stability and high Li+ transport numbers(1). However, the high operating temperature range of molten salts, stemming from high melting temperatures, presents a significant challenge. In this study, we propose Li salts with low melting points achieved through increased entropy and eutectic effects by mixing multi-Li salts. Our focus lies on the anion structure of fluorosulfonyl compounds, aiming to create salts with low melting points. Through mixing of an asymmetric anion salt (Li[N(SO2 CF3)(SO2F)], LiFTA) and versatile Li salts (Li[N(SO2F)2], LiFSA and Li[N(SO2CF3)2)], LiTFSA) we identified compositions with melting points lower than those of individual salts. We investigated the preparation scheme of the salt mixtures, their bulk properties, and electrochemical characteristics.Preparation of mixed salts was conducted in an Ar-filled glove box. Two salts from LiFTA, LiFSA, and LiTFSA were mixed in prescribed molar ratios, dissolved in acetonitrile (AN), and removed AN by heating at 373 K~413 K. The absence of residual AN in the Li mixed salt was confirmed through thermogravimetry (TG-DTA) and differential scanning calorimetry (DSC). The thermal properties of mixed salts were evaluated using TG-DTA and DSC. Ionic conductivity (σ) of the mixed Li salts was measured from 403 K to 263 K, with an alternating current (AC) amplitude of 500 mV over a frequency range of 500 kHz to 50 mHz.For low melting point LiFTA (T m = 376 K), pulsed-field gradient NMR (PFG-NMR) was obtained to measure self-diffusion coefficients (D) of each nucleus (Li+, FTA-) above T m (413 K~378 K). Compared to Li+, FTA- exhibited higher values of D, with activation energies of 74 kJ mol-1 for Li+ and 71 kJ mol-1 for FTA- (Figure 1). The difference in D between Li+ and FTA- suggests individual diffusion of the cation and anion. Figure 2 illustrates DSC profiles of each Li salt (LiFSA, LiTFSA) and mixed salts (LiFSA/LiTFSA). Mixing LiFSA and LiTFSA revealed a eutectic effect in the salt mixtures, particularly evident in the mixed salt Li([FSA]0.6[TFSA]0.4), which exhibited the lowest T m at 391 K. This melting point was lower than that of single salts, highlighting the effectiveness of mixing two versatile Li salts. Furthermore, highly amorphous nature was observed in Li([FSA]0.2[TFSA]0.8) through DSC analysis. The incorporation of LiFTA into the mixed salts (Li([FSA]0.6[TFSA]0.4)) holds promise for fabricating mixed salts with even lower T ms. Figure 3(a) displays DSC profiles of each Li salt (LiFTA, LiFSA) and mixed salts (LiFTA/LiFSA), while Figure 3(b) also depicts those of each Li salt (LiFTA, LiTFSA) and mixed salts (LiFTA/LiTFSA). The prepared mixed salts resulted in either transparent, highly viscous liquids or transparent to white solids. Mixed salts using LiFTA and LiTFSA became complete amorphous, indicating the potential for further reduction in melting points or the creation of supercooled Li ionic liquids.The Arrhenius plot of the ionic conductivity (σ) for Li([FSA]0.6[FTA]0.4) is presented in Figure 4. At 403 K, σ was rather low and 0.18 mS cm-1, which can be attributed to strong interactions between Li+ and the anion in the absence of solvents, resulting in high viscosity and reduced mobility. The conductivities exhibited close values between Li([FSA]0.6[FTA]0.4) and LiFTA. LiFTA showed a change from VFT to Arrhenius-type temperature dependence at 308 K, whereas Li([FSA]0.6[FTA]0.4) revealed stronger supercooling behavior compared to LiFTA.(1)Y. Yamada, A. Yamada, J. Electrochem. Soc., 162, A2406-A2423 (2015). Figure 1

(Invited) Redefined Battery Science and Engineering after 100 Years of Debye-Hückel Theory

In any electrochemical system, electrode potential is the central variable that regulates the driving force of redox reactions. However, quantitative understanding of the electrolyte dependence has been limited to the classic Debye-Hückel theory that approximates the Coulombic interactions in the electrolyte under the dilute limit conditions. Therefore, accurate expression of electrode potential for most of practical electrochemical systems has been a holy grail of electrochemistry research for over a century. Here we show that the ‘liquid Madelung potential’ based on the conventional explicit treatment of solid-state Coulombic interactions enables quantitatively accurate expression of the electrode potential, with the Madelung shift obtained from molecular dynamics reproducing a hitherto-unexplained huge experimental shift for several battery electrode. Furthermore, incorporating the effects of entropy and polarization dynamics could polish the theoretical model to perfectly fit the experimental data. Thus, a long-awaited method for the description of the electrode potential in any electrochemical system is now available after 100 years of classical Debye-Hückel theory.[1] P. Debye & E. Hückel, Physikalische Zeitschrift, 24, 185 (1923), [2] N. Takanaka, et al., and A. Yamada, Denki Kagaku, 91, 140 (2023) [3] S.Ko, et al., and A. Yamada, Next Energy, 100014 (2023), [4] S. Ko, et al.,and A. Yamada, Nature Sustain., 6, 1705 (2023), [5] N. Takenaka, et al., and A.Yamada, Nature Comm., 15, 1319 (2024)

Comparison of dU/dQ, Voltage Decay, and Float Currents via Temperature Ramps and Steps in Li‐ion Batteries

In this study, the effect of temperature changes on the voltage decay and current behavior of lithium‐ion cells is investigated, focusing on a comparison between open‐circuit voltage (OCV) measurements and float current [[EQUATION]] measurements. Using our self‐developed advanced Floater system, the voltage decay rates [[EQUATION]] from OCV and float current measurements for three different cell types are assessed. Temperature ramps and steps, ranging from 5°C to 50°C, are applied to capture the impact of entropic effects and aging mechanisms. Both methods effectively capture aging dynamics, showing strong agreement between ramp and step measurements. Deviations arise only in cases of strong entropy effects due to differences in measurement strategies. The findings confirm that float currents do not introduce additional aging beyond that captured by OCV measurements. The relationship between OCV and float current is governed by differential capacity [[EQUATION]], which varies with cell voltage and temperature. Furthermore, strong deviations from classical differential voltage analysis but high agreement with local pulse measurements are observed, especially at low depths of discharge. This can be explained by the hysteresis effect of graphite. These findings highlight the benefits of high‐precision float current measurements in aging studies, particularly in contrast to simpler OCV methods.

FCC-Based High Entropy Alloy (AlFeCoNiCu) Catalysts for Electrochemical Ammonia Production from Nitrate

Ammonia (NH₃) is one of the most important materials for human activities, finding versatile applications in areas such as fertilizers, hydrogen carrier, and carbon-free energy fuel. Traditionally, NH₃ is produced through the energy-intensive Haber-Bosch (HB) process, resulting in considerable CO₂ emissions. As an alternative, electrochemical NH₃ production is gaining attentions. The electrochemical nitrate reduction reaction (NO₃RR) has been explored due to its advantages, including a low energy barrier, high nitrogen source solubility in the electrolyte, and high activity. In order to produce NH3 electrochemically, transition metal-based alloys have been employed as catalysts due to their features such as high conductivity, synergy effects, and low cost. However, transition metal catalysts suffer from low NH3 selectivity and high activity of hydrogen evolution reaction (HER), which is a competitive reaction. Recently, high-entropy alloy (HEA) catalysts have been employed as catalysts due to their features such as high entropy effect, lattice distortion, cocktail effect, and sluggish diffusion. To enhance the activity and selectivity of the NO₃RR, we developed FCC-based HEA (AlFeCoNiCu) electrocatalyst. The FCC-based HEA catalysts demonstrated a yield rate exceeding 9.88 mg h-1 cm-2 and a faradaic efficiency (FE) of 90.2 % at -0.6 V vs. RHE in 0.1 M NO₃- and 1 M KOH solution. This research is expected to contribute not only to the efficient production of ammonia under ambient conditions but also to the exploration of HEAs catalysts for enhancing the NO3RR pathway.

Unlocking advanced sodium storage performance: High-entropy modulates crystallographic sites with reversible multi-electron reaction

Poor migration dynamics and low energy density are the main challenges of Na3V2(PO4)3 as a cathode material for sodium ion batteries. Herein, a nanoscale polyhedron high-entropy cathode of Na3V1.47(Fe,Al,Ga,Mg,Mn)0.5Mo0.01Nb0.02(PO4)3 is designed to modify the crystal structure and enhance the electrons transfer. Distributed nanoparticles improve the electrolyte interface, promoting rapid migration of Na+, while the abundant specific surface area offers extra sites for Na+ storage. High entropy and multi-metal synergistic effects increase the number of occupied Na(1) and Na(2) sites, maintaining multiple redox couples (V3+/4+/5+ and Mn2+/3+/4+) and obtaining a reversible 2.18-electron reaction. Consequently, the high-entropy cathode of Na3V1.47(Fe,Al,Ga,Mg,Mn)0.5Mo0.01Nb0.02(PO4)3 delivers excellent specific capacity of 130.2 mAh g−1 at 0.5 C, achieving high energy density of 448.3 Wh kg−1, and exhibiting the capacity retention of 95 % after 500 cycles at 5 C and 86.5 % after 1000 cycles at 15 C, respectively. In situ XRD, ex situ XAS and DFT calculations reveal the influence of structural evolution, valence changes, and high-entropy effects on chemical kinetics. This study provides a guideline for designing advanced polyanionic phosphate cathode materials for sodium ion batteries.

Effect of different Ga species in Ga-ZSM-5 on dehydrogenation performance of cyclohexane to benzene

Ga-containing ZSM-5 can effectively promote the dehydrogenation process in the methanol-to-aromatics (MTA) process. However, the forms of gallium species are diversity. It remains elusive which active gallium species has the best dehydrogenation activity. The catalytic activity of dehydrogenation of eight different Ga species (GaH2+, GaO+, Ga2O22+, GaH2+, Ga(OH)2+, Ga(OH)2+, GaH(OH)+, Ga+) in Ga-ZSM-5 was investigated by using DFT calculations in the dehydrogenation of cyclohexane to produce benzene as a model reaction. The DFT results combined with microkinetic calculation results suggested that GaH2+, Ga(OH)2+ and Ga2O22+, especially Ga2O22+, are the most likely species responsible for dehydrogenation. Interaction forces between metal ions and reactants and reactant activation energies show an inverted volcano type relationship. Enthalpy and entropy effects analysis indicate that the dehydrogenation of cyclohexane to benzene on Ga species is dominated by the enthalpy barrier. This opens up the prospect of better understanding the effect of dehydrogenating active species in Ga-doped ZSM-5 on the catalytic reaction.

Lapachol, a natural food component, interacts with human serum albumin: Insights of its impact on the pharmacokinetics of clinically used drugs

Lapachol (LAP), a natural 1,4-naphthoquinone used in popular medicine in South America, is an antioxidant and antimicrobial compound in teas and infusions and used as a food additive; however, its interactive profile with the main protein carrier of compounds in the human bloodstream (human serum albumin, HSA) was not still characterized. Additionally, the impact of LAP in binding clinically drugs to albumin is still unknown. Thus, the present work describes the interaction HSA:LAP using different biophysical techniques, i.e., 1H saturation-transfer difference nuclear magnetic resonance (1H STD-NMR), isothermal titration calorimetry (ITC), steady-state and time-resolved fluorescence measurements combined with molecular docking calculations. LAP interacts with subdomain region IIA (site I), mainly driven by enthalpy effects, while subdomain region IB (site III) was identified as the second binding site, mainly driven by entropy effects. The binding is spontaneous, strong (binding constant average, Kaverage ≈ 4.45 × 105 M−1), and there is a positive cooperativity in the presence of ibuprofen, with the LAP structure fully buried into the protein cavities. Overall, LAP might impact the residence time (pharmacokinetic profile) of drugs that bind to subdomains regions IIA and IB of albumin, e.g., warfarin, phenylbutazone, diflunisal, naproxen, camptothecin, doxorubicin, daunorubicin, suramin, and tyrosine kinase inhibitors.

The effect of entropy on the structure and aqueous durability of nanocrystalline rare-earth zirconate ceramics

A series of compositionally complex A2Zr2O7 nanocrystalline ceramics were successfully prepared using sol-gel and co-precipitation methods. The resultant ceramics possess a cubic defect fluorite structure, with the sol-gel method yielding an average grain size of approximately 50–70 nm, while the co-precipitation method result in an average grain size of about 40–60 nm. Leaching tests revealed that the smaller grain sizes are correlated with higher leaching rates. Furthermore, for ceramics with similar grain sizes, those with higher entropy values exhibited higher leaching rates. The increase in grain boundaries was found to reduce the leaching performance of the rare earth zirconate ceramics, and this effect became more pronounced with increasing entropy. This work provides insights into the selection of entropy values and grain sizes for the high-level radioactive waste matrices, which can be considered as a potential substrate for the simultaneous immobilization of multiple radionuclides.

Effects of A-site configuration entropy on the dielectric properties in tetragonal tungsten bronze ceramics

A series of Sr4.5Ca0.5MTi3Nb7O30 [M = La0.5Nd0.5 (LN), La1/3Nd1/3Sm1/3 (LNS) and La0.25Nd0.25Sm0.25Eu0.25 (LNSE)] ceramics with different A-site configuration entropy were prepared, and the effects of the A-site configuration entropy on the dielectric and ferroelectric properties were investigated. Due to the combined effect of high entropy and solid solution, the best dielectric performance was achieved in the LNS composition, where the dielectric constant remained around 650 in the temperature range of 269–515 K with a change rate of less than 15%. Under the DC high voltage field up to 67 kV/cm, each component's polarization characteristics and dielectric constants obtained good electric field stability and temperature stability under a high electric field.

Misfit Layered Compounds: Insights into Chemical, Kinetic, and Thermodynamic Stability of Nanophases.

ConspectusCompounds with layered structures (2D-materials), like transition metal-dichalcogenides (e.g., MoS2), attracted a great deal of interest in the scientific community in recent years. This interest can be attributed to their unique lamellar structure, which induces large anisotropy in their physicochemical properties. Furthermore, owing to the weak van der Waals interaction between the layers, they can be cleaved along the a-b plane, which allows fabricating single layers with physical properties entirely different from the bulk material. Moreover, stacking layers of different 2D-materials on top of each other has led to a wealth of new observations, for instance, by twisting two layers with respect to each other and producing Moiré lattice. Another outstanding property of inorganic layer compounds is their tendency to form nanotubes, reported first (for WS2) many years ago and subsequently from many other layered compounds.Among the 2D-materials, misfit layer compounds make a special class with an incommensurate and nonstoichiometric lattice made of an alternating layer with rocksalt structure, like LaS (O) and a layer with hexagonal structure, like TaS2 (T). The lack of lattice commensuration between the two slabs leads to a built-in strain, which can be relaxed via bending. Consequently, nanotubes have been produced from numerous MLC compounds over the past decade and their structure was elucidated.Owing to their large surface area, nanostructures are generally metastable and tend to recrystallize into microscopic crystallites via different mechanisms, like Ostwald ripening, or chemically decompose and then recrystallize. The stability of nanostructures at elevated temperatures has been investigated quite scarcely so far. In this perspective, electron microscopy as well as synchrotron-based X-ray absorption and reflection techniques were used to elucidate the chemical selectivity and decomposition routes of rare-earth based MLC nanotubes prepared at elevated temperatures (800-1200 °C).As for the chemical selectivity, entropic effects are expected to dictate the random distribution of the chalcogen atoms on the anion sites of the MLC nanotubes at elevated temperatures. Nonetheless, the sulfur atoms were found to bind exclusively to the rare-earth atom (Ln = La, Sm) of the rocksalt slab and the selenium to the tantalum of the hexagonal TX2 slab. This uncommon selectivity was not found in other kinds of nanotubes like WSe2xS2(1-x). In other series of experiments, the lack of utter symmetry in the multiwall nanotubes leads to exclusions of certain X-ray (0kl) reflections, which was used to distinguish them from the bulk crystallites. The transformation of Ln-based MLC nanotubes into microscopic flakes was followed as a function of the synthesis temperature (800-1200 °C) and the synthesis time (1-96 h). Furthermore, sequential high-temperature transformations of the (O-T) lattice into (O-T-T) and finally (O-T-T-T) phases via deintercalation of the LnS slab was observed. This autocatalytic process is reminiscent of the deintercalation of alkali atoms from different layered structure materials. Annealing at higher temperatures and for longer periods of time eventually leads to the decomposition of the ternary MLC into binary metal-sulfide phases, as well as partial oxidation of the product. This study sheds light on the complex mechanism of high-temperature chemical stability of the nanostructures.