Broad Temperature Research Articles

Triple Regulation of Water Molecules Behavior to Realize High Stability and Broad Temperature Tolerance in Aqueous Zinc Metal Batteries via a Novel Cost‐Effective Eutectic Electrolyte

AbstractThe high activity of water in aqueous electrolyte causes drastic side reactions on the Zn anodes, severely limiting the electrochemical performance of aqueous zinc metal batteries (AZMBs) under extreme conditions. Herein, levulinic acid is developed as the hydrated deep eutectic solvent (DES), to build a novel non‐flammable and cost‐effective ZnSO4‐based eutectic electrolyte with triple regulation of water molecules behavior, enabling highly stable AZMBs over a wide temperature. In situ experiments, molecular dynamics simulations, and spectroscopy analysis jointly reveal that the DES is capable of comprehensively lowering the water activity by simultaneously controlling the behavior of the free, solvated, and interfacial water molecules within the eutectic electrolyte system. Consequently, the Zn anodes exhibit ultralong cycling stability (4500 h at 1 mA cm−2/1 mA h cm−2), decent Coulombic efficiency of 99.39%, and excellent temperature tolerance (−20–50 °C). Notably, the designed 2.0 Ah Zn//VOX pouch cell exhibits a recorded actual energy density of 37.46 Wh Kg−1 and 95.38 Wh L−1 at the whole cell level, with a remarkable capacity retention of 81.01% after 150 cycles, demonstrating the potential for scale‐up into real AZMBs. This work provides an in‐depth understanding of the correlation between the water molecule behavior and electrochemical properties of AZMBs.

Dual Crystal-Liquid Thermal Transport Behavior in MAPbCl3.

Phonon dynamics in organic-inorganic hybrid perovskites (OIHPs) exhibit inherent complexity driven by the intricate interactions between rotatable organic cations and dynamically disordered inorganic octahedra, mediated by hydrogen bonding. This study aims to address this complexity by investigating the thermal transport behavior of MAPbCl3 as a gateway to the OIHPs family. The results reveal that the ultralow thermal conductivity of MAPbCl3 arises from a synergistic interplay of exceptionally low phonon velocities, short phonon lifetimes, and phonon mean free paths approaching the Regel-Ioffe limit. Additionally, the thermal conductivity of MAPbCl3 approaches its theoretical amorphous limit across a broad temperature range, with its thermal transport behavior transitioning from crystal-like to more liquid-like during the orthorhombic-to-cubic phase transitions. Furthermore, a phonon drag effect is observed at 17K, with Umklapp scattering serving as the predominant phonon resistive mechanism in the orthorhombic phase. In contrast, dynamic lattice distortions caused by the jumping rotation of MA+ cations become the primary factors influencing thermal transport in the cubic phase.

Analysis of pyroelectric properties in quenched NBT-BT composition

Quenching has recently demonstrated its efficacy in elevating the ferroelectric to relaxor phase transition temperature (TFR) in 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-6BT). Consequently, the current investigation comprehensively examines the pyroelectric properties of quenched NBT-6BT. The pyroelectric coefficient is measured using the Byer-Roundy method, incorporating a strategic approach to mitigate the risk of overestimation by implementing cyclic heating and cooling. Quenching enhances the depolarization temperature (Td) by approximately 40 °C, quantified through the temperature-dependent pyroelectric current density (Ip). The maximum pyroelectric current (52nA) and voltage (200V) responses to thermal cycling (15s heating/cooling) were observed in quenched NBT-6BT. The voltage sensitivity figures of merit were equivalent for both furnace-cooled and quenched NBT-6BT. The assessment of pyroelectric energy storage involved charging a 48 nF capacitor in 180s, resulting in a maximum voltage of 38V. The outcomes strongly endorse the quenched NBT-6BT as an efficient pyroelectric material, showcasing promising attributes for applications in sensing and energy harvesting across a broad temperature range.

A Mechanical Robust, Self-Healable, Recyclable Elastomer for Damping Over A Broad Temperature Range

A Mechanical Robust, Self-Healable, Recyclable Elastomer for Damping Over A Broad Temperature Range

Exploring the wear mechanism of surface hardfacing Stellite 6 alloy on the cast iron over the wide temperature range

Abstract Cast iron is widely used as a heat-resistant material in the automotive industry, but it increasingly struggles to meet the demands of high-temperature friction applications. This study employs surface hardfacing with Stellite 6 alloy to improve the wear resistance of cast iron. By conducting sliding friction tests at various temperatures, we systematically investigate the friction behavior of both cast iron and hardfacing specimens over a broad temperature range. The results reveal that hardfacing-treated specimens exhibit exceptional wear resistance. At ambient temperatures, the hardfacing specimen shows a 65.5% reduction in wear loss compared to the cast iron specimen. This reduction increases to 83.8% at temperatures up to 600 °C. At room temperature, the wear mechanisms of cast iron include abrasive wear and fatigue wear. At medium temperatures, abrasive wear is the primary mechanism of cast iron. At high temperatures, the wear mechanisms of cast iron consist of abrasive wear, oxidative wear, and adhesive wear. In contrast, the wear mechanisms of the hardfacing specimens differ: at room and medium temperatures, abrasive wear is the predominant mechanism, while at high temperatures, the main mechanisms are abrasive wear and adhesive wear. The superior mechanical properties and enhanced resistance to high-temperature oxidation of the hardfacing specimens are the primary factors contributing to their improved friction performance across the temperature spectrum.

Zero Thermal Expansion via the Unconventional Sublattice‐Magnetovolume Effect in Rare‐Earth Ferrimagnets

AbstractZero thermal expansion (ZTE) alloys are critically needed in sophisticated modern industries, including telescope manufacturing, satellite technology, and semiconductor production, owing to their exceptional dimensional stability. In this study, high‐performance ZTE with a negligible coefficient of thermal expansion αv = 2.7 ppm K−1 over a broad temperature range of 10–220 K is discovered in ErCo2.8Fe0.2 magnet. Owing to an unconventional sublattice‐magnetovolume effect in the Er atoms, the negative thermal expansion in Fe‐substituted ErCo3−xFex magnets can be easily tuned to high‐performance ZTE. Moreover, the direct visualization of the magnetic transition in the predominant magnetization from the Er to the Co/Fe sublattices, as observed by the Lorentz transmission electron microscopy, further elucidates the manipulation mechanism behind the high‐performance ZTE. This study reports a convenient and effective strategy to optimize the thermal expansion characteristics of Er‐Co‐Fe magnets, which can guide future research that broadens the application scope of magnetic materials by leveraging the significant correlation between the magnetic properties and crystal structure of such systems.

Broad temperature span and large electrocaloric effect in lead-free ceramics via multi-strategy synergistic optimization

The rapid advancement of electronic technology has increased power consumption in integrated circuits, presenting significant challenges for efficient cooling. BaTiO3 (BT)-based ceramics offer promising electrocaloric (EC) cooling, providing a compact, efficient alternative to bulky, environmentally harmful vapor compression refrigeration, though temperature span (Tspan) and phase transitions limit their current practicality. This study explores a novel (0.5-x)Ba0.72Sr0.28TiO3-0.5BaTi0.8Sn0.2O3-xBa0.72Ca0.28TiO3 [(0.5-x)BST-BTS-xBCT] ceramic system, leveraging phase boundary engineering to achieve continuous and broad phase transitions. By optimizing grain size and enhancing the breakdown electric field (Eb) through a density adjustment strategy, the 0.2BCT ceramics demonstrated excellent EC performance at 38 °C, with a ΔT of 2.71 K and a Tspan of 49.1 °C. These findings establish (0.5-x)BST-BTS-xBCT ceramics as a promising lead-free material for EC applications with significant potential for improving microelectronic cooling solutions.

Influence of side-methyl substitution position on the phase state and microwave dielectric properties of triphenylacetylene-based liquid crystals.

Liquid crystal materials are well known in display applications, and their unique birefringence and electrical tunability can be utilised in microwave devices. This innovative technology modulates and filters microwave signals, replacing conventional semiconductors for a broad operational frequency band and tunable phase shift. Although isothiocyanatobiphenylacetylene-based liquid crystals exhibit low viscosity and large dielectric anisotropy, their applications in microwave communication are hampered by their broad near-crystalline phase temperature ranges. To address this limitation, this study designed and synthesized six fluorinated biphenylacetylene liquid crystal compounds with various benzene ring side-methyl substitutions (n = 3-5). The molecular structures, liquid crystal phases, and microwave dielectric properties were evaluated. Our findings indicate that compounds with methyl substitution at the Y2 position exhibited reduced melting points, an expanded nematic phase temperature range (ΔT n ≈ 92.3 °C), and an absence of near-crystalline phases. These compounds still maintain high microwave dielectric constants within the 9-30 GHz frequency band (Δε r = 0.9-1.3) and reduced maximum permittivity losses compared to their non-methyl-substituted counterparts, thereby improving the efficiency in the microwave frequency band. In contrast, the Y1 position substitution results in a significantly narrower nematic phase temperature range (approximately 2.6 °C on average) and a substantial decrease in the dielectric constant, with a Δε r reduction of about 0.3 compared to the Y2 substitution. This work shows that the side-methyl substitution can improve the performance of triphenylacetylene-based liquid crystals in microwave communication, providing valuable insight to aid the discovery of novel microwave liquid crystals.

Carbon-based nanocomposites for sensing applications-a review

Abstract Carbon-based nanomaterials exhibit unique morphological and physical properties. When used as fillers in various matrices such as polymers, they can provide enhanced electrical, thermal and mechanical characteristics. The emerging field of sensing technologies has witnessed remarkable advancements, resulting from the integration of carbon-based nanocomposites. This paper presents a comprehensive review of the latest developments in key carbon-based nanocomposite sensors. First, the unique properties of carbon nanomaterials are reviewed covering the full dimensional spectrum, followed by main synthesis routes addressing critical aspects such as morphology, surface functionalization, and doping strategies. Later, the synergistic effects arising from the combination of carbon nanomaterials with other components, such as polymers, are explored in detail, emphasizing the role of percolation levels in the overall sensing performance. The different sensing applications presented in this review cover a broad range, including strain, temperature, gas and biosensing. The mechanisms and principles governing the sensing capabilities of carbon-based nanocomposites are provided, shedding light on the interactions between analytes and nanocomposite surfaces. A critical analysis of current challenges and prospects is also presented, outlining potential avenues for further research and innovation. Finally, this review aims to serve as a valuable resource for researchers interested in carbon-based nanocomposites and their evolving role in advancing sensing technologies.

Enhanced temperature range and stability in LaAlO3 NTC ceramics through Ce-Nb codoping

Negative temperature coefficient (NTC) thermistors have garnered increased attention due to their high sensitivity, low thermal inertia, and cost-effectiveness. However, their practical application is significantly constrained by a limited temperature range and poor stability. In this study, a series of Ce-Nb codoped LaAlO3 ceramics were synthesized using the traditional solid-state reaction method, and their unique electrical properties as NTC thermistors were examined. XRD analysis reveals that Ce-Nb codoping induces lattice distortion in the LaAlO3 ceramics. HAADF-STEM shows that Ce replaces La at A-sites, while Nb substitutes for Al at B-sites. XPS indicates that the substitution of Ce4+ for La3+ and Nb5+ for Al3+ facilitates the formation of oxygen vacancies and enhances the number of free carriers. Electrical resistance and UV measurements demonstrate that increasing the Ce and Nb doping levels improves carrier mobility and reduces the band gap of LaAlO3. These modifications significantly enhance the electrical performance and extend the temperature range to 298 K –1773 K when the Ce doping level is 0.2 and the Nb doping level is 0.1. Additionally, aging tests indicate that Ce-Nb co-doping reduces the aging drift of LaAlO3 to 0.38 % after 500 h of aging at 1273 K. This novel Ce-Nb codoped LaAlO3 ceramic, with its broad temperature range and superior stability, shows significant potential for application in NTC thermistors.

1,8-Diazabicyclo[5.4.0]undec-7-ene as Cyclic Ether Electrolyte Polymerization Inhibition for Wide-Temperature-Range High-Rate Lithium-ion Batteries.

1,3-Dioxolane (DOL), with its broad liquid phase temperature window and low Li+-solvent binding energy, stands out as an ideal solvent candidate for the wide-temperature and high-rate electrolytes. Unfortunately, DOL is susceptible to undergo ring-opening polymerization under common lithium salts, which markedly retards the reaction kinetics. This work introduces the organic basic additive 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) to effectively suppress the polymerization, thus achieving compatibility between LiFSI, LiDFOB lithium salts, and DOL. Furthermore, density functional theory (DFT) calculations are utilized to elucidate the underlying mechanisms of DOL polymerization and to clarify how DBU inhibits its polymerization. The resulting electrolyte, devoid of polymer chain formation, forms a weak solvation structure rich in anions, which demonstrates rapid ion transport kinetics in the bulk electrolyte and excellent electrochemical stability at the electrolyte-electrode interfaces (EEIs) simultaneously. When applied to the LiFePO4||graphite full cell, it exhibits exceptional wide-temperature and high-rate performance, with specific capacities reaching 101.2 mAh g -1 at room temperature (20 C), 36.9 mAh g-1 at -40 °C (0.5 C), and 118.0 mAh g-1 at 60 °C (20 C). This study significantly guides the development of wide-temperature, high-rate electrolytes.

Healable, Recyclable, and Ultra-Tough Waterborne Polyurethane Elastomer Achieved through High-Density Hydrogen Bonding Cross-Linking Strategy.

With the increasing popularity of elastomers in industry and daily life, their high performance and functionality have attracted widespread attention. However, it is a great challenge for them to possess both high mechanical properties and excellent healing and recovery capabilities due to the limitations of the preparation methods and the intrinsic microstructure of the elastomers. In this study, a strategy of ice-controlled interfacial stepwise cross-linking was proposed to prepare the waterborne polyurethane-based elastomers with ultrahigh-density hydrogen bonding interaction achieved by enhancing the utilization rate of phenol hydroxyl groups of tannic acid to the maximum extent. The elastomers have incredible mechanical properties, including ultrahigh toughness of 1.03 GJ m-3 (which represents the highest level among polyurethane elastomers prepared through common processing techniques to date), extremely high true fracture stress of ∼1.9 GPa, world-record fracture energy of 520 kJ m-2, and exciting multiple functional characteristics, such as highly efficient self-healing ability of 10 min, high resistance to physical damage and chemical corrosion, broad temperature and frequency damping effects, good shape memory effect, and excellent melt-processing recyclability and solvent recyclability. These robust multifunctional elastomers represent considerable potential in various fields, from defense and military industry and civil transportation to precision manufacturing, etc.

Hyperbranched Thermosensitive Polymer-AuNP Composite Probe for Temperature Colorimetric Detection.

Temperature detection is particularly important in the medical and scientific fields. Although there are various temperature detection methods, most of them focus on broad temperature detection, and basic research in specific fields, especially the detection of subtle temperature changes (32-34 °C) during wound infection, is still insufficient. For this purpose, a novel colorimetric temperature sensing probe is designed in this paper, which can quickly and intuitively respond to small temperature changes within a specific range through color changes. In this paper, hyperbranched polyethyleneimine (HPEI) was modified by isobutyrylation to prepare hyperbranched temperature-sensitive polymer (HPEI-IBAm). And it was combined with gold nanoparticles (AuNPs) prepared by a sodium citrate reduction method to construct an HPEI-IBAm-AuNP colorimetric probe. The probe exhibits excellent stability, even at salt concentrations of up to 12 g/L, thanks to the abundant amino functional groups and the large steric hindrance effect unique to HPEI-IBAm. In particular, the temperature detection range of the probe is precisely locked within 32-34 °C, enabling it to respond quickly and accurately to small temperature changes of only 2 °C. This feature is perfectly suited to the practical needs of temperature detection in infected wounds. The linear fitting coefficient of the temperature response is as high as 0.9929, ensuring the accuracy of the test results. The detection performance of the probe remained highly consistent over 10 cycles, fully proving its excellent reusability and durability. In addition, a flexible colorimetric sensor was prepared by combining the probe with polydimethylsiloxane (PDMS) film. This sensor is capable of rapidly detecting human skin temperature in real time, achieving an accuracy of 99.07% to 100.61%. It can provide a possible solution to the challenges of delayed and difficult temperature detection caused by different body parts and uneven surfaces, among others. This demonstrates its extensive practical value and potential, and it is expected to be further applied in the monitoring of wound infections.

Latitudinal Patterns and Macroclimatic Drivers of Phylogenetic Structure in Regional Liverwort Assemblages in North America

ABSTRACTAimMost plant groups originated under tropical conditions, leading to the hypothesis of tropical niche conservatism, according to which species assemblages of a clade originating and diversifying in tropical climates are expected to have low phylogenetic diversity and dispersion in temperate climates because only few lineages have adapted to these novel conditions. The opposite may be expected for clades originating under temperate conditions, but this temperate niche conservatism hypothesis has not been tested for a broad temperature gradient including both tropical and arctic climates. Liverworts are thought to have originated in temperate climates, and may thus follow the pattern of temperate niche conservatism. Here, we test this hypothesis using regional liverwort floras across a nearly full temperature gradient from tropical through temperate to arctic climates in North America. In addition, we investigate whether temperature‐related variables and climate extreme variables play a more important role in determining phylogenetic structure of liverwort assemblages, compared to precipitation‐related variables and climate seasonality variables, respectively.LocationNorth America.TaxonLiverworts (Marchantiophyta).MethodsPhylogenetic diversity (measured as mean pairwise distance) and phylogenetic dispersion (measured as standardised effect size of mean pairwise distance) in liverworts in regional floras in North America were related to latitude and climatic variables. Variation partitioning analysis was used to assess the relative importance of temperature‐ versus precipitation‐related variables and of climate extremes versus seasonality on phylogenetic diversity and dispersion.ResultsPhylogenetic diversity and dispersion in liverworts is highest in temperate climates, compared to both tropical and arctic climates. Temperature‐related variables and climate extreme variables explained more variation in phylogenetic diversity and dispersion of liverwort assemblages than did precipitation‐related variables and climate seasonality variables, respectively.Main ConclusionsVariations in phylogenetic diversity and dispersion in liverworts along the latitudinal gradient in North America are consistent with the temperate niche conservatism hypothesis.

Sodium‐Difluoro(oxalato)Borate‐Based Electrolytes for Long‐Term Cycle Life and Enhanced Low‐Temperature Sodium‐Ion Batteries

AbstractSodium‐ion batteries (SIBs) are emerging as a promising alternative for next‐generation energy storage solutions, driven by the economic and environmental benefits of abundant sodium resources. A pivotal aspect of SIB advancement is the development of advanced electrolytes, which remains a formidable challenge. Herein, a facile and scalable synthesis method for low‐cost sodium‐difluoro(oxalato)borate (NaDFOB) is reported and explored its application as a standalone electrolyte salt for SIBs. The NaDFOB‐based ether electrolyte demonstrates exceptional electrochemical stability, solvent compatibility, and the unique capacity to form a dense, robust solid‐electrolyte interphase layer on electrode surfaces. As a result, the Na4Fe3(PO4)2P2O7 (NFPP) cathode with NaDFOB‐based electrolyte exhibits ultrahigh cycling stability with a remarkable capacity retention of 98.7% after 1000 cycles. Furthermore, an Ah‐level hard carbon (HC)//NFPP pouch cell using NaDFOB‐based ether electrolyte shows an impressive cycle life of 500 cycles, coupled with an average Coulombic efficiency of 99.9%. The pouch cells also maintain superior electrochemical performance across a broad temperature range from −40 to 60 °C, showcasing the electrolyte's versatility. This work contributes significant insights into the strategic design and application of innovative salts, paving the way for longer‐lasting SIBs with enhanced electrochemical performance.

Strong Ion‐Dipole Interactions for Stable Zinc‐Ion Batteries with Wide Temperature Range

AbstractAqueous zinc‐ion batteries are widely recognized as promising alternatives to lithium batteries due to their excellent safety, environmental compatibility, and cost‐effectiveness. Nonetheless, the formation of dendrites, corrosion, and undesirable side reactions on the zinc surface pose significant challenges to the cycling stability of zinc‐ion batteries. In this study, polar propylene carbonate (PC) is paired with tetrafluoroborate anions to establish a strong ion‐dipole interaction. Strong ion‐dipole interaction can not only alter the solvation structure of zinc ions but also facilitate the formation of a dynamic double electric layer on the surface of the zinc electrode, suppressing the formation of ZnF2 interface and carbonate, thereby facilitating uniform zinc ion deposition, and consequently improving battery cycling stability over a broad temperature range. Concretely, the formulated electrolyte enhances the cycling stability of the battery over a wide temperature range of −30 to 40 °C, accompanied by a capacity retention of ≈100% even after 10 000 cycles at −30 °C. The symmetrical battery utilizing this electrolyte exhibits stable cycling performance for over 1200 h at 25 °C and 1900 h at −30 °C, respectively. The findings provide a promising direction for the development of long‐cycle batteries capable of operating over a wide temperature range.

Experimental and Theoretical Analysis of Frequency- and Temperature-Dependent Characteristics in Viscoelastic Materials Using Prony Series

This study comprehensively investigates the frequency- and temperature-dependent viscoelastic properties of two elastomer materials, focusing on the comparison between experimental results and theoretical models derived from Prony series coefficients. Dynamic Mechanical Analysis (DMA) was performed across a broad temperature range of 0–100 °C and frequency range of 0.1–100 Hz to generate storage modulus and relaxation modulus data for both materials. Relaxation tests were conducted at 25 °C to further characterize the time-dependent behavior. Time–Temperature Superposition (TTS) was applied to the resultant shift factors used to fit both Williams–Landel–Ferry (WLF) and Arrhenius equations. Additionally, sinusoidal sweep tests were carried out at 0 °C, 25 °C, 50 °C, and 80 °C, with frequencies ranging from 1 Hz to 1000 Hz, to experimentally determine the natural frequencies of the elastomers. The findings demonstrate that Prony series coefficients derived from storage modulus data offer a more accurate prediction of the viscoelastic response and natural frequencies compared to those derived from relaxation modulus data. The storage modulus data closely match the experimentally observed natural frequencies, while the relaxation modulus data exhibit larger deviations, particularly at higher temperatures. The study also reveals temperature-dependent behavior, where increasing temperature reduces the stiffness of the materials, leading to lower natural frequencies. This comprehensive analysis highlights the importance of selecting appropriate modeling techniques and data sources, particularly when predicting dynamic responses under varying temperature and frequency conditions.

Natural cellulose reinforced multifunctional eutectogels for wearable sensors and epidermal electrodes

Wearable electronics significantly impact health monitoring, clinical care, and human-machine interfaces. Eutectogels, which utilize deep eutectic solvents (DES) address the drawbacks of hydrogels, such as weight loss and poor temperature tolerance, as well as the high costs and toxicities associated with ionogels. Despite these advances, most eutectogels serve only as sensors or epidermal electrodes and rarely fulfill both functions simultaneously. In this study, we present a multifunctional eutectogel designed to function in both ways. Incorporating natural cotton cellulose nanofibers as nanofillers reinforced the tensile strength of the resultant eutectogel by 7.47 times compared to that of the pure eutectogel, reaching 4.93 MPa. This eutectogel exhibited high ionic conductivity (1.22 S m−1), strong adhesion (1562.2 kPa to iron), self-healing ability (80.37% strain recovery and 80.53% tensile strength recovery), a broad temperature tolerance (−40 to 80 °C), and antibacterial properties. It demonstrates high sensitivity for the real-time strain detection of human activities and accurately captures electrophysiological signals, enabling the control of a small car. This versatile eutectogel has excellent potential for use in flexible wearable electronics.

Highly efficient CO2 capture on acid-treated sepiolite impregnated with mixed polyethyleneimine and diethanolamine

Amine-functionalized solid adsorbents exhibit broad prospects in CO2 capture from flue gases due to their high adsorption capacity and selectivity. However, reported adsorbents are still facing challenges, including high costs, the easy agglomeration of polyamines, and limited adsorption temperature ranges. In this study, sepiolite-based mixed amine adsorbents are prepared by synergistically impregnating acid-treated sepiolite with a mixture of polyethyleneimine (PEI) and diethanolamine (DEA). Results show that at a PEI/DEA loading ratio of 1:1 and a mixture loading of 60wt%, the CO2 adsorption capacity of the resulting adsorbent increases from 0.58mmol/g for acid-treated sepiolite to 2.89mmol/g at 60°C, and remains above 2.50mmol/g after 10 cycles. Meanwhile, the optimized adsorbent maintains a capacity of over 2.44mmol/g within the temperature range of 30–70°C. Additionally, the CO2 selectivity and maximum heat of adsorption for the optimized adsorbent are calculated to be 1184 and 60.08kJ/mol, respectively. An improved CO2 adsorption capacity is obtained, an increase from 0.052mmol/g for acid-treated sepiolite to 1.60mmol/g. Furthermore, an in-situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) analysis reveals that the introduction of DEA into PEI helps in polyamine dispersion, thereby enhancing CO2 adsorption capacity. The CO2 capture mechanism follows a zwitterionic reaction, where CO2 is ultimately converted into carbamate and carbamic acid. Overall, the as-prepared sepiolite-based mixed amine adsorbents, which are characterized by high CO2 adsorption capacity and selectivity, low cost, broad adsorption temperature range, moderate heat of adsorption, and good cycle stability, show promising potential for industrial applications.

Multiphase critical point type phase boundary induced superior magnetocaloric properties in ferromagnetic Tb1-xGdxCo2 alloys

In this work, we report an exotic combination of magnetic entropy change (ΔSM =4.56 Jkg-1K−1), refrigerant capacity (RC=190.6 J kg−1) and adiabatic temperature change (ΔTad=6.8 K) for varying magnetic fields (ΔH) from 0 to 5 T, with near-zero hysteresis loss at the critical point of multiphase coexistence of rhombohedral, cubic and tetragonal phases at x=0.9 in Tb1−xGdxCo2 alloys. Additionally, the ΔSM curves cover a broad temperature range of 42 K. Further analysis demonstrates that the excellent magnetocaloric performance observed at the multiphase coexistence point stems from the flattening free energy, which provides minimal energy barriers, enabling magnetic spins to switch between different crystal symmetries.