Hydrochars derived from real organic wastes as carbonaceous precursors of activated carbons for the removal of NO from contaminated gas streams

The improvement of air quality in densely-populated urban regions constitutes an environmental challenge of increasing concern. In this respect, the abatement of NO emissions, primarily emanating from combustion processes associated with motor-vehicles, along with industrial/domestic combustion systems, represents one of the main problems. Here, three hydrochars from diverse organic residues were used as activated carbon precursors for their evaluation in the NO removal in two potential application scenarios. Hydrochars were physically activated at 800 °C with pure-CO2 or diluted-O2. These materials were tested in a lab-scale biofilter at different conditions (NO concentration, temperature, relative humidity, NO-containing gas and carbon particle size) and in a larger-scale biofilter to evaluate the long-term NO removal capacity. Hydrochar-derived carbons present a relatively well-developed micro- and mesoporous structure, with BET areas of up to 421 m2/g, and a variety of oxygen surface functionalities (carboxylic, lactone, carbonyl and quinone groups), especially concerning CO2-activated carbons. These exhibited an excellent behaviour at low NO concentration (5 ppmv) between 25 and 75 °C with removal capacities of ≈97 % and > 82 %, respectively; and still good-performance (≈66 %) in a more concentrated gas (120 ppmv). Whilst, carbons obtained by diluted-O2 activation from the same hydrochars, evidenced a higher removal capacity loss at high NO concentration. The O2 presence in the gas stream was confirmed as a crucial factor in the NO elimination, since both co-adsorb on the carbon surface favouring NO oxidation to NO2. Besides, the humidity in the airstream diminished the NO removal capacity from 0.88 to 0.51 mgNO/gcarbon, but still remained at 0.54 mgNO/gcarbon, when the carbon (in pellet) was operated at larger-scale biofilter in 9-fold longer test under humid air. Therefore, this study highlights the potential of renewable carbons to serve as cost-effective component in urban biofilters, to mitigate NO emissions from exhaust gases in biomass boilers and urban semi-close areas.

Progress in food packaging applications of biopolymer-nanometal composites - A comprehensive review

Eco-friendly nanotechnology-enabled biopolymers are one of the novel concepts of packaging materials to substitute traditional synthetic polymers and their composites. This article succinctly reviews the recent developments of introducing additional functionalities to biopolymers using metal and metal oxide nanoparticles. The functionality of metal nanoparticles such as silver, zinc oxide, titanium dioxide, copper oxide, gold, and magnesium oxide, as food packaging materials were discussed. The addition of nanoparticles in biopolymers improves mechanical properties, gas barrier properties, durability, temperature stability, moisture stability, antimicrobial activity, antioxidant property, and UV absorbance and can prevent the presence of ethylene and oxygen, hence extending the shelf life of foodstuffs. Other than this, the functional activity of these biopolymer composite films helps them to act like smart or intelligent packaging. The selection of metal nanoparticles, particle migration, toxicological effect, and potential future scope in the food packaging industry are also reviewed.

A review of biocompatible polymer-functionalized two-dimensional materials: Emerging contenders for biosensors and bioelectronics applications

Bioelectronics, a field pivotal in monitoring and stimulating biological processes, demands innovative nanomaterials as detection platforms. Two-dimensional (2D) materials, with their thin structures and exceptional physicochemical properties, have emerged as critical substances in this research. However, these materials face challenges in biomedical applications due to issues related to their biological compatibility, adaptability, functionality, and nano-bio surface characteristics. This review examines surface modifications using covalent and non-covalent-based polymer-functionalization strategies to overcome these limitations by enhancing the biological compatibility, adaptability, and functionality of 2D nanomaterials. These surface modifications aim to create stable and long-lasting therapeutic effects, significantly paving the way for the practical application of polymer-functionalized 2D materials in biosensors and bioelectronics. The review paper critically summarizes the surface functionalization of 2D nanomaterials with biocompatible polymers, including g-C3N4, graphene family, MXene, BP, MOF, and TMDCs, highlighting their current state, physicochemical structures, synthesis methods, material characteristics, and applications in biosensors and bioelectronics. The paper concludes with a discussion of prospects, challenges, and numerous opportunities in the evolving field of bioelectronics.

Europium insertion into MgAl hydrotalcite-like compound to promote the photocatalytic oxidation of nitrogen oxides

Easy synthesis of efficient, non-toxic photocatalysts is a target to expand their potential applications. In this research, the role of Eu3+ doping in the non-toxic, affordable, and easily prepared MgAl hydrotalcite-like compounds (HTlcs) was explored in order to prepare visible light semiconductors. Eu doped MgAl-HTlcs (MA-xEu) samples were prepared using a simple coprecipitation method (water, room temperature and atmospheric pressure) and europium was successfully incorporated into MgAl HTlc frameworks at various concentrations, with x (Eu3+/M3+ percentage) ranging from 2 to 15. Due to the higher ionic radius and lower polarizability of Eu3+ cation, its presence in the metal hydroxide layer induces slight structural distortions, which eventually affect the growth of the particles. The specific surface area also increases with the Eu content. Moreover, the presence of Eu3+ 4f energy levels in the electronic structure enables the absorption of visible light in the doped MA-xEu samples and contributes to efficient electron-hole separation. The microstructural and electronic changes induced by the insertion of Eu enable the preparation of visible light MgAl-based HTlcs photocatalysts for air purification purposes. Specifically, the optimal HTlc photocatalyst showed improved NOx removal efficiency, ∼ 51% (UV-Vis) and 39% (visible light irradiation, 420 nm), with excellent selectivity (> 96 %), stability (> 7 h), and enhanced release of •O2- radicals. Such results demonstrate a simple way to design photocatalytic HTlcs suitable for air purification technologies.

Effect of Coffee Thermocycling on Color Stability and Translucency of CAD-CAM Polychromatic High Translucent Zirconia Compared With Lithium Disilicate Glass Ceramic

AIMS AND OBJECTIVES

To evaluate the effect of coffee thermocycling on color stability and translucency of CAD-CAM polychromatic high translucent zirconia compared with lithium disilicate glass ceramic.

METHODS

Sixteen rectangular plates (14 × 16 × 1.0 mm) of two ceramic materials (IPS E.max CAD (IEC), IPS E.max ZirCAD Prime [IZP]) were prepared. Each specimen was measured for color coordinates using a spectrophotometer following 30,000 cycles of coffee thermocycling. CIELAB formula was used to determine color and translucency differences (ΔE and ΔTP). The means of ΔE and ΔTP were compared using independent samples t-test and were evaluated using their respective 50%:50% perceptibility and acceptability thresholds (PT and AT). One-way analysis of variance was performed to evaluate the translucency parameter (TP) and surface roughness (Ra) of each material.

RESULTS

Mean ΔE values of IEC (4.69) and IZP (4.64) were higher than the AT (ΔE ≤ 2.7) with no significant difference found between the two groups (p = 0.202). Considering the TP, only IEC showed a statistically significant increase in TP value (p < 0.001). However, the mean ΔTP of IEC (3.25) remained within the range of acceptability (1.3 < ΔTP ≤ 4.4).

CONCLUSIONS

Within the limitations of this current study, the color stability of all materials was clinically affected by coffee thermocycling. In terms of translucency, only lithium disilicate glass ceramic was influenced by coffee thermocycling. High translucent zirconia had superior translucency stability compared to lithium disilicate glass ceramic.

High-Pressure Synthesis and Recovery of Single Crystals of the Metastable Manganese Carbide, MnCx

Transition metal carbides find widespread use throughout industry due to their high strength and resilience under extreme conditions. However, they remain largely limited to compounds formed from the early d-block elements, since the mid-to-late transition metals do not form thermodynamically stable carbides. We report here the high-pressure bulk synthesis of large single crystals of a novel metastable manganese carbide compound, MnCx (P63/mmc), which adopts the anti-NiAs-type structure with significant substoichiometry at the carbon sites. We demonstrate how synthesis pressure modulates the carbon loading, with ~40 % occupancy being achieved at 9.9 GPa.

First-principles study on structural stabilities, mechanical properties, and biaxial strain-induced superconductivity in Janus MoWC monolayer

The unique attributes of hydrophilicity, expansive surface groups, remarkable flexibility, and superior conductivity converge in MXene, a pioneering 2D material. Owing to MXene's exceptional properties, diverse strategies have been explored to enhance its characteristics. Janus MXene and stress-strain response considerations represent the primary avenues of interest today. In this study, we investigated the Janus MXene structure under biaxial stress using first-principles calculations. The most stable configuration of Janus MoWC MXene identified in our analysis exhibits an atomic arrangement known as the hexagonal (2H) phase. Subsequently, we examined the mechanical and electronic properties of 2H-MoWC when subjected to biaxial strain. Our findings indicate that the 2H phase of Janus MoWC MXene demonstrates superior strength compared to the tetragonal (1T) phase. Analysis of the ELF of the 2H-MoWC structure unveiled that the robust C-C bond within the material is the underlying factor enabling the 2H phase to withstand a maximum of 9% tensile strain. Furthermore, we demonstrate that 2H-MoWC is a superconductor with the superconducting temperature (Tc) of 1.6 K, and the superconductivity of 2H phase can be enhanced by biaxial strain with the Tc reaching 7 K. This study offers comprehensive insights into the properties of Janus MoWC monolayer under biaxial stress, positioning it as a promising candidate for 2D straintronic applications.

Revealing the Two-Stage Charging Process in Sulfuric Acid Electrolyte by Molecular Dynamics Simulation

Two-dimensional MXene materials perform excellently in supercapacitor applications, but self-stacking and overlap limit their applications. Constructing a reasonable layered structure by combining MXene and graphene can effectively inhibit the restacking and overlap of MXene and improve the performance of supercapacitors. In this work, we studied the energy storage performance of a conventional MXene electrode and MXene/graphene composite electrode in sulfuric acid aqueous electrolyte by molecular dynamics (MD) simulation and analyzed their energy storage mechanisms. The simulation results reveal that the MXene/graphene composite electrode showed faster charge-discharge speed and larger capacity and had more obvious advantages as a cathode. The charging process of the composite cathode can be divided into two stages. In the first stage, SO42- and H3O+ enter the electrode as a whole in a nearly 1:2 ratio, and a unique three-layer structure is formed in the graphene area, while a large number of HSO4- leaves the electrode. In the second stage, SO42- with a part of H3O+ (ratio of 2:2 to 2:3) leave the electrode, and the three-layer structure is gradually destroyed. The cooperation of these two stages leads to a particular "concave" in the total energy change of the composite cathode. The introduction of graphene has brought about changes in ion distribution, migration mechanism, and energy change, making the MXene/graphene cathode show significant advantages in energy storage. This work is of great significance for understanding the microscopic energy storage mechanism of MXene/graphene-based electrodes.

Two-Dimensional MXene-Based Electrocatalysts: Challenges and Opportunities

MXene, regarded as cutting-edge two-dimensional (2D) materials, have been widely explored in various applications due to their remarkable flexibility, high specific surface area, good mechanical strength, and interesting electrical conductivity. Recently, 2D MXene has served as a ideal platform for the design and development of electrocatalysts with high activity, selectivity, and stability. This review article provides a detailed description of the structural engineering of MXene-based electrocatalysts and summarizes the uses of 2D MXene in hydrogen evolution reactions, nitrogen reduction reactions, oxygen evolution reactions, oxygen reduction reactions, and methanol/ethanol oxidation. Then, key issues and prospects for 2D MXene as a next-generation platform in fundamental research and real-world electrocatalysis applications are discussed. Emphasis will be given to material design and enhancement techniques. Finally, future research directions are suggested to improve the efficiency of MXene-based electrocatalysts.

Transferable, Living Data Sets for Predicting Global Minimum Energy Nanocluster Geometries

Modeling of nanocluster geometries is essential for studying the dependence of catalytic activity on the available active sites. In heterogeneous catalysis, the interfacial interaction of the support with the metal can result in modification of the structural and electronic properties of the clusters. To tackle the study of a diverse array of cluster shapes, data-driven methodologies are essential to circumvent prohibitive computational costs. At their core, these methods require large data sets in order to achieve the necessary accuracy to drive structural exploration. Given the similarity in binding character of the transition metals, cluster shapes encountered for various systems show a large amount of overlap. This overlap has been utilized to construct a living data set which may be carried over across multiple studies. Iterative refinement of this data set provides a low-cost pathway for initialization of cluster studies. It is shown that utilization of transferable structural information can reduce model construction costs by more than 90%. The benefits of this approach are particularly notable for alloy systems, which possess significantly larger configurational spaces compared to the pure-phase counterparts.

Synthesis, magnetic and NMR spectroscopic properties of the MAl5Pt3 series (M = Ca, Y, La-Nd, Sm-Er)

Following recent investigation in the ternary system Sr-Al-Pt led to the discovery of SrAl5Pt3 which crystallizes in the orthorhombic YNi5Si3 type (Pnma) structure. Interestingly, only two more aluminum representatives, CeAl5Pt3 and EuAl5Pt3, have been reported to adopt this structure type. Therefore, we decided to investigate the existence range of compounds adopting the YNi5Si3 type structure. Besides the already known Sr, Ce and Eu members, the series could be extended to Ca, Y and La-Nd as well as Sm-Er. All compounds were synthesized from the elements and characterized by powder X-ray diffraction. While for CaAl5Pt3 and LaAl5Pt3 also the respective M2Al16Pt9 members were observed, the other compounds could be obtained either as X-ray pure materials or with small amounts of Al3Pt2 as a side phase. The structure of ErAl5Pt3 could be refined from single crystal data, verifying that also the small rare-earth elements adopt the YNi5Si3 type structure. Selected members of the series were furthermore characterized by magnetization and susceptibility measurements. Since YAl5Pt3 could be obtained as a phase pure material and exhibits no paramagnetic behaviour it was investigated by 27Al MAS NMR investigations. Also, XPS measurements were conducted on this compound to gain an insight into the charge distribution. Finally, quantum-chemical calculations supported the NMR measurements and gave an insight into the chemical bonding and the charge distribution.

Engineered Two-Dimensional Transition Metal Dichalcogenides for Energy Conversion and Storage

Designing efficient and cost-effective materials is pivotal to solving the key scientific and technological challenges at the interface of energy, environment, and sustainability for achieving NetZero. Two-dimensional transition metal dichalcogenides (2D TMDs) represent a unique class of materials that have catered to a myriad of energy conversion and storage (ECS) applications. Their uniqueness arises from their ultra-thin nature, high fractions of atoms residing on surfaces, rich chemical compositions featuring diverse metals and chalcogens, and remarkable tunability across multiple length scales. Specifically, the rich electronic/electrical, optical, and thermal properties of 2D TMDs have been widely exploited for electrochemical energy conversion (e.g., electrocatalytic water splitting), and storage (e.g., anodes in alkali ion batteries and supercapacitors), photocatalysis, photovoltaic devices, and thermoelectric applications. Furthermore, their properties and performances can be greatly boosted by judicious structural and chemical tuning through phase, size, composition, defect, dopant, topological, and heterostructure engineering. The challenge, however, is to design and control such engineering levers, optimally and specifically, to maximize performance outcomes for targeted applications. In this review we discuss, highlight, and provide insights on the significant advancements and ongoing research directions in the design and engineering approaches of 2D TMDs for improving their performance and potential in ECS applications.

Magneto-Optical Ceramics with High Transparency for Highly Sensitive Magnetometer via Quantum Weak Measurement

Sensitive magnetometer technology is desirable for biomagnetic field detection and geomagnetic field measuring. Signal amplification materials such as magneto-optical crystals or ceramics are crucial for enhancing detection sensitivity, but severe optical scattering and low Verdet constant further limit its application. To develop high-sensitivity magnetometers for quantum weak measurement schemes, we have conducted investigations on the powder calcining dynamics and prepared a series of high-optical-quality (Ho/Dy)2Zr2O7 transparent ceramic samples. The Verdet constant of magneto-optical materials was measured across a continuous wavelength spectrum, exhibiting a peak at 283 ± 5 rad/(T·m). We further established an electron transition mechanism to elucidate the exceptional magneto-optical attributes of dysprosium. In addition, samples demonstrated superior performance in weak-value amplification, reaching a low detectable magnetic field threshold of 3.5 × 10-8 T and continuously worked over 6 h with high stability. Our work developed a highly sensitive magnetometer using optimized magneto-optical ceramics and provided guidance on design, fabrication, and application for magneto-optical ceramics in quantum weak measurement.

Cation Vacancies Enable Anion Redox in Li Cathodes

Conventional Li-ion battery intercalation cathodes leverage charge compensation that is formally associated with redox on the transition metal. Employing the anions in the charge compensation mechanism, so-called anion redox, can yield higher capacities beyond the traditional limitations of intercalation chemistry. Here, we aim to understand the structural considerations that enable anion oxidation and focus on processes that result in structural changes, such as the formation of persulfide bonds. Using a Li-rich metal sulfide as a model system, we present both first-principles simulations and experimental data that show that cation vacancies are required for anion oxidation. First-principles simulations show that the oxidation of sulfide to persulfide only occurs when a neighboring vacancy is present. To experimentally probe the role of vacancies in anion redox processes, we introduce vacancies into the Li2TiS3 phase while maintaining a high valency of Ti. When the cation sublattice is fully occupied and no vacancies can be formed through transition metal oxidation, the material is electrochemically inert. Upon introduction of vacancies, the material can support high degrees of anion redox, even in the absence of transition metal oxidation. The model system offers fundamental insights to deepen our understanding of structure-property relationships that govern reversible anion redox in sulfides and demonstrates that cation vacancies are required for anion oxidation, in which persulfides are formed.

Advances in MXene-based technologies for the remediation of toxic phenols: A comprehensive review

The pressing global issue of organic pollutants, particularly phenolic compounds derived primarily from industrial wastes, poses a significant threat to the environment. Although progress has been made in the development of low-cost materials for phenolic compound removal, their effectiveness remains limited. Thus, there is an urgent need for novel technologies to comprehensively address this issue. In this context, MXenes, known for their exceptional physicochemical properties, have emerged as highly promising candidates for the remediation of phenolic pollutants. This review aims to provide a comprehensive and critical evaluation of MXene-based technologies for the removal of phenolic pollutants, focusing on the following key aspects: (1) The classification and categorization of phenolic pollutants, highlighting their adverse environmental impacts, and emphasizing the crucial need for their removal. (2) An in-depth discussion on the synthesis methods and properties of MXene-based composites, emphasizing their suitability for environmental remediation. (3) A detailed analysis of MXene-based adsorption, catalysis, photocatalysis, and hybrid processes, showcasing current advancements in MXene modification and functionalization to enhance removal efficiency. (4) A thorough examination of the removal mechanisms and stability of MXene-based technologies, elucidating their operating conditions and stability in pollutant removal scenarios. (5) Finally, this review concludes by outlining future challenges and opportunities for MXene-based technologies in water treatment, facilitating their potential applications. This comprehensive review provides valuable insights and innovative ideas for the development of versatile MXene-based technologies tailored to combat water pollution effectively.

Electrochromic windows with fast response and wide dynamic range for visible-light modulation without traditional electrodes

Electrochromic (EC) devices represent an emerging energy-saving technology, exhibiting the capability to dynamically modulate light and heat transmittance. Despite their promising potential, the commercialization of EC devices faces substantial impediments such as high cost, intricate fabrication process, and low optical contrast inherent in conventional EC materials relying on the ion insertion/extraction mechanism. In this study, we introduce an innovative "electrode-free" electrochromic (EC) device, termed the EECD, which lacks an EC-layer on the electrodes during device assembling and in the bleached state. This device features a simplified fabrication process and delivers superior optical modulation. It achieves a high optical contrast ranging from 68-85% across the visible spectrum and boasts a rapid response time, reaching 90% coloring in just 17 seconds. In addition, EECD exhibits stable cycling for over 10,000 cycles without noticeable degradation and maintains functionality across a broad temperature range (0 °C to 50 °C). Furthermore, the fabricated large-area devices (40 cm × 40 cm) demonstrate excellent tinting uniformity, suggesting excellent scalability of this approach. Our study establishes a paradigmatic breakthrough for EC smart windows.

Three Perovskite Phases with Different Cation Orders in Sm2MnMn(Mn4-xSbx)O12

Cation order, which can be controlled by synthesis conditions and stoichiometry, plays an important role in properties of perovskite materials. Here we show that aliovalent doping by Sb5+ in Sm2MnMn(Mn4-xSbx)O12 quadruple perovskite solid solutions can control cation orders in both A and B sites. Samples with 0.4≤x≤2 were synthesized by a high-pressure, high-temperature method at 6 GPa and 1770 K. Three regions with different cation orders were found at 0.5≤x≤1.0, x=1.5-1.6, and x=1.8. The 0.5≤x≤1.0 compositions have a B-site-disordered and A-site columnar-ordered structure with space group P42/nmc; the x=1.5 and 1.6 samples have a B-site rock-salt-ordered and A-site columnar-ordered structure with space group P42/n; the x=1.8 sample has a B-site rock-salt-ordered and A-site-disordered structure with space group P21/n. All the samples show one ferrimagnetic transition: TC increases from 35 K to 73 K for 0.5≤x≤1.0, TC=81 K for x=1.5 and 1.6, and TC=53 K for x=1.8.

Carbon Dots: A Review with Focus on Sustainability

Carbon dots (CDs) are an emerging class of nanomaterials with attractive optical properties, which promise to enable a variety of applications. An important and timely question is whether CDs can become a functional and sustainable alternative to incumbent optical nanomaterials, notably inorganic quantum dots. Herein, the current CD literature is comprehensively reviewed as regards to their synthesis and function, with a focus on sustainability aspects. The study quantifies why it is attractive that CDs can be synthesized with biomass as the sole starting material and be free from toxic and precious metals and critical raw materials. It further describes and analyzes employed pretreatment, chemical-conversion, purification, and processing procedures, and highlights current issues with the usage of solvents, the energy and material efficiency, and the safety and waste management. It is specially shown that many reported synthesis and processing methods are concerningly wasteful with the utilization of non-sustainable solvents and energy. It is finally recommended that future studies should explicitly consider and discuss the environmental influence of the selected starting material, solvents, and generated byproducts, and that quantitative information on the required amounts of solvents, consumables, and energy should be provided to enable an evaluation of the presented methods in an upscaled sustainability context.

Core-shell nanogels: the effects of morphology, electro- and magnetostatic interactions

We study the influence of core-shell morphology on the structural characteristics of nanogels. Using computer simulations, we examine three different types of systems, distinguished by their intermonomer interactions: those with excluded volume only; those with charged monomers and excluded volume; and those with excluded volume combined with a certain number of magnetised nanoparticles incorporated within the nanogel. We observe that if the polymers in the shell are short and dense, they tend to penetrate the core. This effect of backfolding is enhanced in charged nanogels, regardless of whether all monomers are charged, or only the core or shell ones. The presence of an experimentally available amount of magnetic nanoparticles in a gel, on the one hand, does not lead to any significant morphological changes. On the other hand, the morphology of the nanogel with magnetic particles has an impact on its magnetic susceptibility. Particular growth of the magnetic response is observed if a long shell of a nanogel is functionalised.

The role of graphene aerogels in rechargeable batteries

Energy storage systems, particularly rechargeable batteries, play a crucial role in establishing a sustainable energy infrastructure. Today, researchers focus on improving battery energy density, cycling stability, and rate performance. This involves enhancing existing materials or creating new ones with advanced properties for cathodes and anodes to achieve peak battery performance. Graphene aerogels (GAs) possess extraordinary attributes, including a hierarchical porous and lightweight structure, high electrical conductivity, and robust mechanical stability. These qualities facilitate the uniform distribution of active sites within electrodes, mitigate volume changes during repeated cycling, and enhance overall conductivity. When integrated into batteries, GAs expedite electron/ion transport, offer exceptional structural stability, and deliver outstanding cycling performance. This review offers a comprehensive survey of the advancements in the preparation, functionalization, and modification of GAs in the context of battery research. It explores their application as electrodes and hosts for the dispersion of active material nanoparticles, resulting in the creation of hybrid electrodes for a wide range of rechargeable batteries including lithium-ion batteries (LIBs), Li-metal-air batteries, sodium-ion batteries (SIBs), zinc-ion batteries (AZIBs) and zinc-air batteries (ZABs), aluminum-ion batteries (AIBs) and aluminum-air batteries and other.

(Ca0.5Mn0.5)2MnTeO6 - An Anomalously Stable High-Pressure Double Perovskite

High pressure high temperature treatments of the composition CaMnMnTeO6 are found to yield only an A2BB'O6-type double perovskite (Ca0.5Mn0.5)2MnTeO6, rather than a AA'BB'O6 double double perovskite with A- and B- site cation order as found in analogs CaMnMnReO6 and CaMnMnWO6 with similar cation sizes. Double perovskite (Ca0.5Mn0.5)2MnTeO6 adopts a monoclinic structure in space group P21/n with a framework of highly tilted MnO6 and TeO6 octahedra enclosing disordered Ca2+ and Mn2+ cations. Magnetic measurements show that (Ca0.5Mn0.5)2MnTeO6 is a highly frustrated spin glass with a freezing transition at 5 K, and no long-range spin order is apparent by neutron diffraction at 1.6 K.

Monolithic DNApatite: An Elastic Apatite with Sub-Nanometer Scale Organo-Inorganic Structures

Hydroxyapatite (HA) exhibits outstanding biocompatibility, bioactivity, osteoconductivity, and natural anti-inflammatory properties. Pure HA, ion-doped HA, and HA-polymer composites are investigated, but critical limitations such as brittleness remain; numerous efforts are being made to address them. Herein, the novel self-crystallization of a polymeric single-stranded deoxyribonucleic acid (ssDNA) without additional phosphate ions for synthesizing deoxyribonucleic apatite (DNApatite) is presented. The synthesized DNApatite, DNA1Ca2.2(PO4)1.3OH2.1, has a repetitive dual phase of inorganic HA crystals and amorphous organic ssDNA at the sub-nm scale, forming nanorods. Its mechanical properties, including toughness and elasticity, are significantly enhanced compared with those of HA nanorod, with a Young's modulus similar to that of natural bone.

Wavelength-Dependent Activity of Oxygen Species in Propane Conversion on Rutile TiO2(110)

Photocatalytic oxidative dehydrogenation of propane (C3H8) into propene (C3H6) under mild conditions holds great potential in the chemical industry, but understanding how active species participate in C3H8 conversion remains a significant challenge. Here, the wavelength-dependent activities of bridging oxygen (Ob2-) and the Ti5c-bound oxygen adatom (OTi2-) of model rutile (R) TiO2(110) in C3H8 conversion have been investigated. Under 257 and 343 nm irradiation, hole-trapped OTi- and Ob- can abstract the hydrogen atom of C3H8, forming the CH3CH•CH3 radical and C3H6. However, the rate of C3H8 conversion with hole-trapped Ob- is strongly dependent on the wavelength, primarily producing the C3H7• radical. In the case of hole-trapped OTi-, C3H6 is the main product, which is nearly independent of wavelength. The differences in the wavelength-dependent activity and product selectivity are likely due to dynamic control rather than thermodynamic control. The result provides a deeper understanding of the dynamic processes involved in the conversion of light alkanes in TiO2 photocatalysis.

Combined First-Principles and Experimental Investigation into the Reactivity of Codeposited Chromium-Carbon under Pressure

High-pressure synthesis in the diamond anvil cell suffers from the lack of a general approach for the control of precursor stoichiometry and homogeneity. Here, we present results from a new method we have developed that uses magnetron cosputtering to prepare stoichiometrically precise and atomically mixed amorphous films of Cr:C. Laser-heated diamond anvil cell experiments carried out on a flake of this sample at pressures between 13.5 and 24.3 GPa lead to the observation of Cr3C (Pnma) over the entire pressure range-in good agreement with our in-house theoretical predictions-but also reveal two other metastable phases that were not expected: a novel monoclinic chromium carbide phase and the NaCl-type CrC (Fm3̅m) phase. The unexpected stability of CrC is investigated by using first-principles methods, revealing a large stabilizing effect tied to substoichiometry at the carbon site. These results offer an important case study into the current limitations of crystal structure prediction methods with regard to phase complexity and bolster the growing need for advanced theoretical approaches that can more completely survey experimentally unexplored phase space.

Beyond metals: theoretical discovery of semiconducting MAX phases and their potential application in thermoelectrics

MAX phase is a family of ceramic compounds, typically known for their metallic properties. However, we show here that some of them may be narrow bandgap semiconductors. Using a series of first-principles calculations, we have investigated the electronic structures of 861 dynamically stable MAX phases. Notably, Sc2SC, Y2SC, Y2SeC, Sc3AuC2, and Y3AuC2 have been identified as semiconductors with band gaps ranging from 0.2 to 0.5 eV. Furthermore, we have assessed the thermodynamic stability of these systems by generating ternary phase diagrams utilizing evolutionary algorithm techniques. Their dynamic stabilities are confirmed by phonon calculations. Additionally, we have explored the potential thermoelectric efficiencies of these materials by combining Boltzmann transport theory with first-principles calculations. The relaxation times are estimated using scattering theory. The zT coefficients for the aforementioned systems fall within the range of 0.5 to 2.5 at temperatures spanning from 300 to 700 K, indicating their suitability for high-temperature thermoelectric applications.

First-principles study of the structure, magnetism, and electronic properties of the all-Heusler alloy Co2MnGe/CoTiMnGe(100) heterojunction

Based on first-principles calculations in the density functional theory, we systematically investigated the possible interface structure, magnetism, and electronic properties of the all-Heusler alloy Co2MnGe/CoTiMnGe(100) heterojunction. The calculation indicated that the Co2MnGe Heusler alloy is a half-metal with a magnetic moment of 4.97 μB. CoTiMnGe is a narrow-band gap semiconductor and may act as an ultra-sensitive photocatalyst. We cannot find an "ideal" spin-polarization of 100% in CoCo termination and MnGe termination. Due to the interface interaction, the direct magnetic hybridization or indirect RKKY exchange will be weakened, leading to an increase in the atomic magnetic moment of the interfacial layer. For eight possible heterojunction structures, the half-metallic gaps in the Co2MnGe bulk have been destroyed by the inevitable interface states. The spin-polarization value of 94.31% in the CoCo-TiGe-B heterojunction revealed that it is the most stable structure. It is feasible to search for high-performance magnetic tunnel junction by artificially constructing suitable all-Heusler alloy heterojunctions.

Additive manufacturing of dental ceramics in prosthodontics: The status quo and the future

PURPOSE

This review aims to summarize the available technologies, material categories, and prosthodontic applications of additive manufacturing (AM) dental ceramics, evaluate the achievable accuracy and mechanical properties in comparison with current mainstream computer-aided design/computer-aided manufacturing (CAD/CAM) subtractive manufacturing (SM) methods, and discuss future prospects and directions.

STUDY SELECTION

This paper is based on the latest reviews, state-of-the-art research, and existing ISO standards on AM technologies and prosthodontic applications of dental ceramics. PubMed, Web of Science, and ScienceDirect were amongst the sources searched for narrative reviews.

RESULTS

Relatively few AM technologies are available and their applications are limited to crowns and fixed partial dentures. Although the accuracy and strength of AM dental ceramics are comparable to those of SM, they have the limitations of relatively inferior curved surface accuracy and low strength reliability. Furthermore, functionally graded additive manufacturing (FGAM), a potential direction for AM, enables the realization of biomimetic structures, such as natural teeth; however, specific studies are currently lacking.

CONCLUSIONS

AM dental ceramics are not sufficiently developed for large-scale clinical applications. However, with additional research, it may be possible for AM to replace SM as the mainstream manufacturing technology for ceramic restorations.

Elastic strain mapping of plastically deformed materials by TEM

A method for mapping elastic strains by TEM in plastically deformed materials is presented. A characteristic feature of plastically deformed materials, which cannot be handled by standard strain measurement method, is the presence of orientation gradients. To circumvent this issue, we couple orientation and strain maps obtained from scanning precession electron diffraction datasets. More specifically, orientation gradients are taken into account by 1) identifying the diffraction spot positions in a reference pattern, 2) measuring the disorientation between the diffraction patterns in the map and the reference pattern, 3) rotating the coordinate system following the measured disorientation at each position in the map, 4) calculating strains in the rotated coordinate system. At present, only azimuthal rotations of the crystal are handled. The method is illustrated on a Cr2AlC monocrystal micropilar deformed in near simple flexion during a nanomechanical test. After plastic deformation, the sample contains dislocations arranged in pile-ups and walls. The strain-field around each dislocation is consistent with theory, and a clear difference is observed between the strain fields around pile-ups and walls. It is further remarked that strain maps allow for the orientation of the Burgers vector to be identified. Since the loading undergone by the sample is known, this also allows for the position of the dislocation sources to be estimated. Perspectives for the study of deformed materials are finally discussed.

Influence of Long Milling Time on the Electrical Resistivity of Nanocrystalline Ni2MnSn Heusler Alloy Obtained by Mechanosynthesis

A Ni2MnSn Heusler alloy was obtained as a single B2 phase after 12 h of mechanical milling. The influence of prolonged milling on the phase stability was analysed for milling times up to 50 h, related to mean crystallite size, lattice strain, and electrical resistivity. The nature of the powders in the milled range was found to be nanocrystalline, with a mean crystallite size of about 33 ± 2 nm. An evaluation of the internal stresses induced by milling was performed, a linear behaviour was found, and a coefficient of the internal stress increase with milling time was proposed. Particle size distributions of milled samples were analysed, and the morphology of the powders was visualised by scanning electron microscopy. The elemental distribution of milled samples was quantified by energy-dispersive X-ray spectroscopy. Electrical resistivity measurements were performed on compacted samples, and their behaviour with milling time was analysed.

A systematic first-principles investigation of the structural, electronic, mechanical, optical, and thermodynamic properties of Half-Heusler ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) for spintronics and optoelectronics applications

This paper is the first to look at the structural, electronic, mechanical, optical, and thermodynamic properties of the ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) half-Heusler (HH) using DFT based first principles method. The lattice parameters that we have calculated are very similar to those obtained in prior investigations with theoretical and experimental data. The positive phonon dispersion curve confirm the dynamical stability of ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn). The electronic band structure and DOS confirmed that the studied materials ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) are direct band gap semiconductors. The investigation also determined significant constants, including dielectric function, absorption, conductivity, reflectivity, refractive index, and loss function. These optical observations unveiled our compounds potential utilization in various electronic and optoelectronic device applications. The elastic constants were used to fulfill the Born criteria, confirming the mechanical stability and ductility of the solids ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn). The calculated elastic modulus revealed that our studied compounds are elastically anisotropic. Moreover, ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) has a very low minimum thermal conductivity (Kmin), and a low Debye temperature (θD), which indicating their appropriateness for utilization in thermal barrier coating (TBC) applications. The Helmholtz free energy (F), internal energy (E), entropy (S), and specific heat capacity (Cv) are determined by calculations derived from the phonon density of states.

Solid-state polymer-particle hybrid electrolytes: Structure and electrochemical properties

Solid-state electrolytes (SSEs) are challenged by complex interfacial chemistry and poor ion transport through the interfaces they form with battery electrodes. Here, we investigate a class of SSE composed of micrometer-sized lithium oxide (Li2O) particles dispersed in a polymerizable 1,3-dioxolane (DOL) liquid. Ring-opening polymerization (ROP) of the DOL by Lewis acid salts inside a battery cell produces polymer-inorganic hybrid electrolytes with gradient properties on both the particle and battery cell length scales. These electrolytes sustain stable charge-discharge behavior in Li||NCM811 and anode-free Cu||NCM811 electrochemical cells. On the particle length scale, Li2O retards ROP, facilitating efficient ion transport in a fluid-like region near the particle surface. On battery cell length scales, gravity-assisted settling creates physical and electrochemical gradients in the hybrid electrolytes. By means of electrochemical and spectroscopic analyses, we find that Li2O particles participate in a reversible redox reaction that increases the effective CE in anode-free cells to values approaching 100%, enhancing battery cycle life.

Cu2(OH)3NO3/γ-Al2O3 catalyzes Fenton-like oxidation for the advanced treatment of effluent organic matter (EfOM) in fermentation pharmaceutical wastewater: The synergy of Cu2(OH)3NO3 and γ-Al2O3

The secondary effluent of fermentation pharmaceutical wastewater exhibits high chromaticity, elevated salinity, and abundant refractory effluent organic matter (EfOM), presenting significant treatment challenges and environmental threats. Herein, Cu2(OH)3NO3/γ-Al2O3 was fabricated through ultrasound-assisted impregnation and calcination to catalyze the Fenton-like oxidation for degrading organic pollutants in this secondary effluent. Under neutral conditions, with 400.00 mg/L H2O2, 8 g/L catalyst, and at 30 ℃, the EfOM and CODCr removal efficiencies can reach 96.90 % and 51.56 %, respectively. The Cu2(OH)3NO3/γ-Al2O3 catalyst possesses ideal reusability, maintaining CODCr, chromaticity, and EfOM removal efficiencies at 44.44 %-64.59 %, 85.45 %-93.45 %, and 61.00 %-95.00 % over 220 h in a continuous-flow catalytic oxidation system operated at room temperatures (15-25 ℃). Electron paramagnetic resonance results and density functional theory calculations indicate that •OOH may be the predominant reactive oxygen species, facilitated by the easier elongation of the OH bond in H2O2 compared to the OO bond. The adjusted electronic structure endows Cu2(OH)3NO3/γ-Al2O3 composite sites with superior catalytic selectivity for H2O2 activation compared to Cu2(OH)3NO3 single crystal sites, with γ-Al2O3 additionally facilitating H2O2 activation through electron donation. This research highlights the efficacy of Cu2(OH)3NO3/γ-Al2O3 in the advanced treatment of complex industrial wastewater, elucidating its catalytic mechanisms and potential applications.

Carbon carrier-based rapid Joule heating technology: a review on the preparation and applications of functional nanomaterials

Compared to conventional heating techniques, the carbon carrier-based rapid Joule heating (CJH) method is a new class of technologies that offer significantly higher heating rates and ultra-high temperatures. Over the past few decades, CJH technology has spawned several techniques with similar principles for different application scenarios, including ultra-fast high temperature sintering (UHS), carbon thermal shock (CTS), and flash Joule heating (FJH), which have been widely used in material preparation research studies. Functional nanomaterials are a popular direction of research today, mainly including nanometallic materials, nanosilica materials, nanoceramic materials and nanocarbon materials. These materials exhibit unique physical, chemical, and biological properties, including a high specific surface area, strength, thermal stability, and biocompatibility, making them ideal for diverse applications across various fields. The CJH method is a remarkable approach to producing functional nanomaterials that has attracted attention for its significant advantages. This paper aims to delve into the fundamental principles of CJH and elucidate the efficient preparation of functional nanomaterials with superior properties using this technique. The paper is organized into three sections, each dedicated to introducing the process and characteristics of CJH technology for the preparation of three distinct material types: carbon-based nanomaterials, inorganic non-metallic materials, and metallic materials. We discuss the distinctions and merits of the CJH method compared to alternative techniques in the preparation of these materials, along with a thorough examination of their properties. Furthermore, the potential applications of these materials are highlighted. In conclusion, this paper concludes with a discussion on the future research trends and development prospects of CJH technology.

Reactive Synthesis for Porous (Mo2/3Y1/3)2AlC Ceramics through Mo, Y, Al and Graphite Powders

Through an activation reaction sintering method, porous (Mo2/3Y1/3)2AlC ceramics were prepared by Mo, Y, Al, and graphite powders as raw materials. The phase composition, microstructure, element distribution, and pore structure characteristics were comprehensively studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Archimedes method, and bubble point method. A detailed investigation was conducted on the influence of sintering temperature on the phase composition. Possible routes of phase transition and pore formation mechanisms during the sintering process were provided. The experimental results reveal that at 650-850 °C, transition metals react with aluminum, forming aluminum-containing intermetallics and a small amount of carbides. At 850-1250 °C, transition metals collaborate with graphite, producing transition metal carbides. Then, at 1250-1450 °C, these aluminum intermetallics interact with transition metal carbides and remaining unreacted Y, Al, and C, yielding the final product (Mo2/3Y1/3) 2AlC. Simultaneously, the pore structure alters correspondingly with the solid-phase reaction at different reaction temperatures.

Characterization of NiCuOxNy Coatings Obtained via RF Sputtering: Structure, Morphology, and Optical Properties

The rapid advancement of technology necessitates the continual development of versatile materials that can adapt to new electronic devices. Rare earth elements, which are scarce in nature, possess the set of properties required for use as semiconductors. Consequently, this research aims to achieve similar properties using materials that are abundant in nature and have a low commercial cost. To this end, nickel and copper were utilized to synthesize thin films of nickel-copper binary oxynitride via reactive RF sputtering. The influence of nitrogen flow on the structure, morphology, chemical composition, and optical properties of the films was investigated using various characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS), as well as transmittance and absorbance measurements. The crystalline structure of the films shows that they can have preferential growth or be polycrystalline according to the nitrogen flow used during deposition and that both the oxides and oxynitrides of metals are formed. We identified unknown phases specific to this material, termed "NiCuOxNy". The morphology revealed that the grain size of the coatings was dependent on the nitrogen flow rate, with grain size decreasing as the nitrogen flow rate increased. Notably, the coatings demonstrated transparency for wavelengths exceeding 1000 nm, with an optical band gap ranging from 1.21 to 1.86 eV.

Determining Structures of Layer-by-Layer Spin-Coated Zinc Dicarboxylate-Based Metal-Organic Thin Films

Thin films of crystalline solids with substantial free volume built from organic chromophores and metal secondary building units (SBUs) are promising for engineering new optoelectronic properties through control of interchromophore coupling. Zn-based SBUs are especially relevant in this case because they avoid quenching the chromophore's luminescence. We find that layer-by-layer spin-coating using Zn acetate dihydrate and benzene-1,4-dicarboxylic acid (H2BDC) and biphenyl-4,4'-dicarboxylic acid (H2BPDC) linkers readily produces crystalline thin films. However, analysis of the grazing-incidence wide-angle X-ray scattering (GIWAXS) data reveals the structures of these films vary significantly with the linker, and with the metal-to-linker molar ratio used for fabrication. Under equimolar conditions, H2BPDC creates a type of structure like that proposed for SURMOF-2, whereas H2BDC generates a different metal-hydroxide-organic framework. Large excess of Zn2+ ions causes the growth of layered zinc hydroxides, irrespective of the linker used. Density functional theory (DFT) calculations provide structural models with minimum total energy that are consistent with the experimentally observed diffractograms. In the broader sense, this work illustrates the importance in this field of careful structure determination, e. g., by utilizing GIWAXS and DFT simulations to determine the structure of the obtained crystalline metal-organic thin films, such that properties can be rationally engineered and explained.

Achievements, challenges, and perspectives in the design of polymer binders for advanced lithium-ion batteries

Energy storage devices with high power and energy density are in demand owing to the rapidly growing population, and lithium-ion batteries (LIBs) are promising rechargeable energy storage devices. However, there are many issues associated with the development of electrode materials with a high theoretical capacity, which need to be addressed before their commercialization. Extensive research has focused on the modification and structural design of electrode materials, which are usually expensive and sophisticated. Besides, polymer binders are pivotal components for maintaining the structural integrity and stability of electrodes in LIBs. Polyvinylidene difluoride (PVDF) is a commercial binder with superior electrochemical stability, but its poor adhesion, insufficient mechanical properties, and low electronic and ionic conductivity hinder its wide application as a high-capacity electrode material. In this review, we highlight the recent progress in developing different polymeric materials (based on natural polymers and synthetic non-conductive and electronically conductive polymers) as binders for the anodes and cathodes in LIBs. The influence of the mechanical, adhesion, and self-healing properties as well as electronic and ionic conductivity of polymers on the capacity, capacity retention, rate performance and cycling life of batteries is discussed. Firstly, we analyze the failure mechanisms of binders based on the operation principle of lithium-ion batteries, introducing two models of "interface failure" and "degradation failure". More importantly, we propose several binder parameters applicable to most lithium-ion batteries and systematically consider and summarize the relationships between the chemical structure and properties of the binder at the molecular level. Subsequently, we select silicon and sulfur active electrode materials as examples to discuss the design principles of the binder from a molecular structure point of view. Finally, we present our perspectives on the development directions of binders for next-generation high-energy-density lithium-ion batteries. We hope that this review will guide researchers in the further design of novel efficient binders for lithium-ion batteries at the molecular level, especially for high energy density electrode materials.

Facile Synthesis of Organic-Inorganic Hybrid Heterojunctions of Glycolated Conjugated Polymer-TiO2-X for Efficient Photocatalytic Hydrogen Evolution

The utilization of the organic-inorganic hybrid photocatalysts for water splitting has gained significant attention due to their ability to combine the advantages of both materials and generate synergistic effects. However, they are still far from practical application due to the limited understanding of the interactions between these two components and the complexity of their preparation process. Herein, a facial approach by combining a glycolated conjugated polymer with a TiO2-X mesoporous sphere to prepare high-efficiency hybrid photocatalysts is presented. The functionalization of conjugated polymers with hydrophilic oligo (ethylene glycol) side chains can not only facilitate the dispersion of conjugated polymers in water but also promote the interaction with TiO2-X forming stable heterojunction nanoparticles. An apparent quantum yield of 53.3% at 365 nm and a hydrogen evolution rate of 35.7 mmol h-1 g-1 is achieved by the photocatalyst in the presence of Pt co-catalyst. Advanced photophysical studies based on femtosecond transient absorption spectroscopy and in situ, XPS analyses reveal the charge transfer mechanism at type II heterojunction interfaces. This work shows the promising prospect of glycolated polymers in the construction of hybrid heterojunctions for photocatalytic hydrogen production and offers a deep understanding of high photocatalytic performance by such heterojunction photocatalysts.

Hydroxyapatite synthesis and characterization from waste animal bones and natural sources for biomedical applications

Hydroxyapatites (HAps) synthesized from waste animal bones have recently gained attention due to their outstanding properties. This is because there is a need to fabricate scaffolds with desirable mechanical strength, ability to withstand high temperatures, and insoluble in solvents such as water, acetone, ethanol, and isopropyl alcohol. This study is an extensive summary of many articles on the routes of synthesis/preparation of HAp, and the optimum processing parameter, and the biomedical application areas, such as: drug administration, dental implants, bone tissue engineering, orthopedic implant coatings, and tissue regeneration/wound healing. A broad catalog of the synthesis methods (and combination methods), temperature/time, shape/size, and the calcium-to-phosphorous (Ca/P) value of diverse waste animal bone sources were reported. The alkaline hydrolysis method is proposed to be suitable for synthesizing HAp from natural sources due to the technique's ability to produce intrinsic HAp. The method is also preferred to the calcination method owing to the phase transformation that takes place at high temperatures during calcinations. However, calcinations aid in removing impurities and germs during heating at high temperatures. When compared to calcination technique, alkaline hydrolysis method results in crystalline HAp; the higher degree of crystallinity is disadvantageous to HAp bioactivity. In addition, the standardization and removal of impurities and contaminants, thorough biocompatibility to ensure clinical safety of the HAp to the human body, and improvement of the mechanical strength and toughness to match specific requirements for the various biomedical applications are the important areas for future studies.

Hydroxide-Derived Nanostructures: Scalable Synthesis, Characterization, Properties, and Potential Applications

Metal oxide nanostructures have received an increasing attention owing to their unique chemical and physical properties along with their widespread applications in various fields. This article provides an overview of the recent discovery - christened Hydroxides-Derived Nanostructures, or HDNs - in which hydroxide aqueous solutions (mostly tetramethylammonium hydroxide, TMAH) are reacted at temperatures < 100 °C and under atmospheric pressure with various metal-containing precursors to scalably prepare novel metal oxide nanostructures. In one case, a dozen commercial and earth abundant Ti-containing powders such as binary carbides, nitrides, borides, among others, are converted into new, 1D TiO2-based lepidocrocite (1DL) nanofilaments (NFs). Application-wise, the 1DLs show outstanding performance in a number of energy, environmental, and biomedical fields such as photo- and electrocatalysis, water splitting, lithium-sulfur and lithium-ion batteries, water purification, dye degradation, cancer therapy, and polymer composites. In addition to 1DL, the HDNs family encompasses other metal oxides nanostructures including magnetic Fe3O4 nanoparticles and MnO2 birnessite-based crystalline 2D flakes. The latter showed promise in electrochemical energy conversion and storage applications. The developed recipe provides a new vista in the molecular self-assembly synthesis of nanomaterials that can advance the field with a library of novel nanostructures with substantial implications in a multitude of fields.

Turning Ultra-Low Coercivity and Ultra-High Temperature Stability Within 897 K via Continuous Crystal Ordering Fluctuations

High-performance soft magnetic materials are important for energy conservation and emission reduction. One challenge is achieving a combination of reliable temperature stability, high resistivity, high Curie temperature, and high saturation magnetization in a single material, which often comes at the expense of intrinsic coercivity-a typical trade-off in the family of soft magnetic materials with homogeneous microstructures. Herein, a nanostructured FeCoNiSiAl complex concentrated alloy is developed through a hierarchical structure strategy. This alloy exhibits superior soft magnetic properties up to 897 K, maintaining an ultra-low intrinsic coercivity (13.6 A m-1 at 297 K) over a wide temperature range, a high resistivity (138.08 µΩ cm-1 at 297 K) and the saturation magnetization with only a 16.7% attenuation at 897 K. These unusual property combinations are attributed to the dual-magnetic-state nature with exchange softening due to continuous crystal ordering fluctuations at the atomic scale. By deliberately controlling the microstructure, the comprehensive performance of the alloy can be tuned and controlled. The research provides valuable guidance for the development of soft magnetic materials for high-temperature applications and expands the potential applications of related functional materials in the field of sustainable energy.

Boosting Upconversion Efficiency in Optically Inert Shelled Structures with Electroactive Membrane through Electron Donation

This study innovatively addresses challenges in enhancing upconversion efficiency in lanthanide-based nanoparticles (UCNPs) by exploiting Shewanella oneidensis MR-1, a microorganism capable of extracellular electron transfer. Electroactive membranes, rich in c-type cytochromes, are extracted from bacteria and integrated into membrane-integrated liposomes (MILs), encapsulating core-shelled UCNPs with an optically inactive shell, forming UCNP@MIL constructs. The electroactive membrane, tailored to donate electrons through the inert shell, independently boosts upconversion emission under near-infrared excitation (980 or 1550 nm), bypassing ligand-sensitized UCNPs. The optically inactive shell restricts energy migration, emphasizing electroactive membrane electron donation. Density functional theory calculations elucidate efficient electron transfer due to the electroactive membrane hemes' highest occupied molecular orbital being higher than the valence band maximum of the optically inactive shell, crucial for enhancing energy transfer to emitter ions. The introduction of a SiO2 insulator coating diminishes light enhancement, underscoring the importance of unimpeded electron transfer. Luminescence enhancement remains resilient to variations in emitter or sensitizing ions, highlighting the robustness of the electron transfer-induced phenomenon. However, altering the inert shell material diminishes enhancement, emphasizing the role of electron transfer. This methodology holds significant promise for diverse biological applications. UCNP@MIL offers an advantage in cellular uptake, which proves beneficial for cell imaging.

Haze factor of silver nanowires in variable refractive index environment: experimental and simulation approaches

While silver nanowires (Ag NWs) have been demonstrated as a highly efficient transparent conducting material, they suffer from strong light scattering, which is quantified by a large haze factor (HF) in the optical spectrum. Here we investigate the influence of the dielectric environment on the light scattering of Ag NWs by comparing experimental measurements and simulations. In air, two peaks on the HF spectra are observed experimentally at the wavelength ofλI= 350 nm andλII= 380 nm and are attributed by simulations to the influence of the Ag NWs pentagonal shape on the localized surface plasmon resonance. The relative intensity between the two peaks is found to be dependent on whether the Ag NWs are in contact with the glass substrate or not. The HF behaviour in the near IR region seems to be dominated by Rayleigh scattering following simulations results. Dielectric environments of Ag NWs with various refractive indexes were obtained experimentally by the conformal deposition of different metal oxide coatings using atomic layer deposition, including Al-doped zinc oxide, Al2O3and SiO2coatings. The HF is found to be correlated with the refractive index environment in terms of HF peaks position, intensity and broadening. This trend of HF peaks is supported by a theoretical model to understand the optical mechanism behind this phenomenon.

Thin Layers of Cerium Oxynitride Deposited via RF Sputtering

Thin films of transition metal oxides and oxynitrides have proven highly effective in protecting stainless steels against corrosion in both chemically aggressive environments and biological fluids. In the present work, cerium zirconium oxynitride thin films were deposited to enhance the corrosion resistance of surgical-grade stainless steel to be used in osteosynthesis processes. Two techniques were employed: co-sputtering and radiofrequency (RF) sputtering, and the morphology and corrosion efficiency of the coatings deposited by each technique were evaluated. X-ray diffraction, X-ray photoelectron spectroscopy and field emission transmission electron microscopy were used to characterize the morphological and chemical structure, respectively. Additionally, the corrosion resistance of the oxynitride-coated surgical grade stainless steel system (ZrCeOxNy-AISI 316L) was assessed using Hank's solution as the corrosive electrolyte, to determine its resistance to corrosion in biological media. The results show that ZrCeOxNy coatings increase the corrosion resistance of surgical grade stainless steel by two orders of magnitude and that the Ce(III)/Ce(IV) equilibrium decreases the corrosion rate, thereby increasing the durability of the steel in a biological environment. The results show that Ce coatings increase the corrosion resistance of surgical grade stainless steel by two orders of magnitude and that the Ce(III)/Ce(IV) equilibrium decreases the corrosion rate, thereby increasing the durability of the steel in a biological environment.

Photocatalytic systems: reactions, mechanism, and applications

The photocatalytic field revolves around the utilization of photon energy to initiate various chemical reactions using non-adsorbing substrates, through processes such as single electron transfer, energy transfer, or atom transfer. The efficiency of this field depends on the capacity of a light-absorbing metal complex, organic molecule, or substance (commonly referred to as photocatalysts or PCs) to execute these processes. Photoredox techniques utilize photocatalysts, which possess the essential characteristic of functioning as both an oxidizing and a reducing agent upon activation. In addition, it is commonly observed that photocatalysts exhibit optimal performance when irradiated with low-energy light sources, while still retaining their catalytic activity under ambient temperatures. The implementation of photoredox catalysis has resuscitated an array of synthesis realms, including but not limited to radical chemistry and photochemistry, ultimately affording prospects for the development of the reactions. Also, photoredox catalysis is utilized to resolve numerous challenges encountered in medicinal chemistry, as well as natural product synthesis. Moreover, its applications extend across diverse domains encompassing organic chemistry and catalysis. The significance of photoredox catalysts is rooted in their utilization across various fields, including biomedicine, environmental pollution management, and water purification. Of course, recently, research has evaluated photocatalysts in terms of cost, recyclability, and pollution of some photocatalysts and dyes from an environmental point of view. According to these new studies, there is a need for critical studies and reviews on photocatalysts and photocatalytic processes to provide a solution to reduce these limitations. As a future perspective for research on photocatalysts, it is necessary to put the goals of researchers on studies to overcome the limitations of the application and efficiency of photocatalysts to promote their use on a large scale for the development of industrial activities. Given the significant implications of the subject matter, this review seeks to delve into the fundamental tenets of the photocatalyst domain and its associated practical use cases. This review endeavors to demonstrate the prospective of a powerful tool known as photochemical catalysis and elucidate its underlying tenets. Additionally, another goal of this review is to expound upon the various applications of photocatalysts.

Ba4RuMn2O10: A Noncentrosymmetric Polar Crystal Structure with Disordered Trimers

Phase-pure polycrystalline Ba4RuMn2O10 was prepared and determined to adopt the noncentrosymmetric polar crystal structure (space group Cmc21) based on results of second harmonic generation, convergent beam electron diffraction, and Rietveld refinements using powder neutron diffraction data. The crystal structure features zigzag chains of corner-shared trimers, which contain three distorted face-sharing octahedra. The three metal sites in the trimers are occupied by disordered Ru/Mn with three different ratios: Ru1:Mn1 = 0.202(8):0.798(8), Ru2:Mn2 = 0.27(1):0.73(1), and Ru3:Mn3 = 0.40(1):0.60(1), successfully lowering the symmetry and inducing the polar crystal structure from the centrosymmetric parent compounds Ba4T3O10 (T = Mn, Ru; space group Cmca). The valence state of Ru/Mn is confirmed to be +4 according to X-ray absorption near-edge spectroscopy. Ba4RuMn2O10 is a narrow bandgap (∼0.6 eV) semiconductor exhibiting spin-glass behavior with strong magnetic frustration and antiferromagnetic interactions.

Fullerenol as a nano-molecular sieve additive enables stable zinc metal anodes

Aqueous zinc batteries (AZBs) with the advantages of safety, low cost, and sustainability are promising candidates for large-scale energy storage devices. However, the issues of interface side reactions and dendrite growth at the zinc metal anode (ZMA) significantly harm the cycling lifespan of AZBs. In this study, we designed a nano-molecular sieve additive, fullerenol (C60(OH)n), which possesses a surface rich in hydroxyl groups that can be uniformly dispersed in the aqueous solution, and captures free water in the electrolyte, thereby suppressing the occurrence of interfacial corrosion. Besides, fullerenol can be further reduced to fullerene (C60) on the surface of ZMA, holding a unique self-smoothing effect that can inhibit the growth of dendritic Zn. With the synergistic action of these two effects, the fullerenol-contained electrolyte (FE) enables dendrite-free ZMAs. The Zn-Ti half-cell using FE exhibits stable cycling over 2500 times at 5 mA cm-2 with an average Coulombic efficiency as high as 99.8 %. Additionally, the Zn-NaV3O8 cell using this electrolyte displays a capacity retention rate of 100 % after 1000 cycles at -20 °C. This work provides important insights into the molecular design of multifunctional electrolyte additives.

Calorimetric, optical and dielectric measurements on two Schiff's based liquid crystalline materials exhibiting multiple phase transitions

We report high-resolution calorimetric, optical and dielectric studies on two Schiff's based liquid crystalline materials, 4O.5 and 5O.5, which exhibit multiple phase transitions. The study goes beyond the commonly studied isotropic-to-nematic (I-N) and nematic-to-smectic A (N-SmA) phase transitions and explores higher-order smectic phase transitions. The critical exponent, α values, for different phase transitions has been explored. For the I-N, N-SmA, SmA-SmC, SmC-SmF, SmF-CrG and SmB-CrG transitions, α values close to 0.5 and amplitude ratios A-/A+ ~ 1.6 and D-/D+ ~ 1 indicate a first-order nature. Notably, for the SmA-SmB transition, although α (≈ 0.64) is larger than the tricritical value of 0.5, A-/A+ ~ 1.2 and D-/D+ ~ 1, and the study reports an order parameter critical exponent (β) of 0.26 ± 0.002, which supports a tricritical nature for this transition. Importantly, the ratios of A-/A+ and D-/D+ are found to have similar values across all three-measurement methods, indicating consistency and agreement among these methods.

Zintl Phase versus Covalent Metal: Chemical Bonding in Silicon Dumbbells of Ca5Si3 and CaSi3

Silicon dumbbells constitute identifiable anionic molecular species in Zintl phases and so-called covalent metals holding units with homopolar bonding inside a metallic framework. Based on electron-precise Ca5Si3 and metallic CaSi3, the chemical bonding in Si2 units is investigated by computational quantum chemical methods considering the dual nature of the wave function. This concerted wave-vector and real space study substantiates that the Si2 dumbbells in Ca5Si3 can be referred to as molecular building units Si26- with additional metallic and ionic contributions in the solid. In the covalent metal CaSi3, however, the bonding within the dumbbells falls short of fulfilling the octet rule. As a result, antibonding states of the Si2 building units are depopulated and attend metallic interactions, simultaneously giving rise to stronger covalent Si-Si bonds.

Interpenetrated Lattices of Quaternary Chalcogenides Displaying Magnetic Frustration, High Na-Ion Conductivity, and Cation Redox in Na-Ion Batteries

A series of quaternary selenides, NaxMGaSe4 (M = Mn, Fe, and mixed Zn/Fe), have been synthesized for the first time employing a high-temperature solid-state synthesis route through stochiometric or polychalcogenide flux reactions. Along with the selenides, a previously reported sulfide analogue, NaxFeGaS4, is also revisited with new findings. These compounds form an interpenetrated structure made up of a supertetrahedral unit. The electrochemical evaluations exhibit a reversible (de)intercalation of ∼0.6 and ∼0.45 Na-ions, respectively, from Na2.87FeGaS4 (1a) and Na2.5FeGaSe4 (2) involving Fe2+/Fe3+ redox when cycled between 1.5 and 2.5 V. Mössbauer spectroscopy of 1a shows the existence of a mixed oxidation state of Fe2+/3+ in the pristine compound and reversible oxidation of Fe2+ to Fe3+ during the electrochemical cycles. Na2.79Zn0.6Fe0.4GaSe4 possesses a reasonably high room temperature ionic conductivity of 0.077 ms/cm with an activation energy of 0.30 eV. The preliminary magnetic measurements show a bifurcation of FC-ZFC at 4.5 and 2.5 K, respectively, for 1a and Na3MnGaSe4 (4) arising most likely from a spin-glass like transition. The high negative values of the Weiss constants -368.15 and -308.43 K for 1a and 4, respectively, indicate strong antiferromagnetic interactions between the magnetic ions and also emphasize the presence of a high degree of magnetic frustration in these compounds.