Search Results (2,648)

Mullite porous ceramics show exceptional promise for high-temperature insulation applications. However, the mechanical strength and thermal insulation performance of porous ceramics typically cannot be optimized simultaneously. Herein, we proposed a novel method to overcome this limitation by synthesizing hierarchically porous mullite ceramics assembled from ultrathin two-dimensional nanosheets. A chemical blowing method first synthesized ultrathin mullite nanosheets approximately 2–3 nm thick, which were subsequently assembled into a rigid hierarchical network by gel casting and freeze-drying. The influence of solid content and sintering temperature on the phase composition, microstructure, mechanical properties, and high-temperature thermal stability of porous ceramics was systematically investigated. The results indicate that the 20 wt.% sample sintered at 1200 °C exhibited the best performance. This optimal sample achieved a porosity of 90.75%, a compressive strength of 0.38 MPa, and excellent thermal insulation properties, including a low apparent thermal conductivity of 0.0756 W/(m·K) at room temperature and a back surface temperature of 253.2 °C after exposure to a 1200 °C flame. Crucially, this porous ceramic maintained structural stability up to 1500 °C. This nanosheet assembly strategy successfully reinforced the structural skeleton while inhibiting heat transfer. This strategy has great promise for the fabrication of lightweight porous ceramics designed for extreme environments. Full article

Two-dimensional transition metal dichalcogenides (TMDCs) require highly controllable and scalable synthesis methods for successful integration into next-generation optoelectronic technologies. This study presents a modified two-step thermally assisted conversion approach for synthesizing 2D tungsten diselenide (WSe₂) by introducing an intermediate UV–ozone treatment. Magnetron-sputtered tungsten films are exposed to UV–ozone, converting the precursor into a uniform, dense layer of amorphous tungsten trioxide (WO₃) prior to the selenization process via chemical vapor deposition. X-ray photoelectron spectroscopy and Raman spectroscopy confirm the complete phase transition from the oxidized precursor to the 2H-WSe₂ crystal lattice. Morphological evaluations utilizing transmission electron microscopy and atomic force microscopy demonstrate that the ozonated precursors yield highly uniform, triangular flakes exceeding 5 µm in lateral size, effectively eliminating the unreacted WO₃ phases observed in untreated samples. Furthermore, the intermediate oxidation step finetunes the electronic band structure; the resulting WSe₂ exhibits an enhanced p-type character with a valence band maximum shift to 0.35 eV, a tuning attributed to residual oxygen doping. Optical characterizations reveal significantly improved transmittance in the visible spectrum, accompanied by excitonic absorption shifts indicative of reduced layer dimensionality. This intermediate ozonation strategy provides a highly effective pathway for producing high-quality WSe₂ nanosheets with tailored structural and optoelectronic properties. Full article

The global demand for hydrogen peroxide (H₂O₂) continues to increase, and photocatalytic H₂O₂ production is regarded as a promising alternative technology due to its mild, safe, and environmentally friendly characteristics. ZnIn₂S₄ has demonstrated promising application potential in photocatalytic H₂O₂ production owing to its unique two-dimensional layered structure and broad spectral response. However, its performance is severely limited by rapid charge recombination and sluggish charge migration. To address this challenge, a ZnIn₂S₄/C₃N₄ S-scheme heterojunction was successfully constructed via a simple oil-bath method by assembling ZnIn₂S₄ nanoflowers on C₃N₄ nanosheets. Systematic structural characterizations and performance evaluations demonstrate that the construction of the S-scheme heterojunction effectively promotes the spatial separation and surface migration of photogenerated charge carriers, thereby significantly enhancing photocatalytic activity. Under optimal conditions, the ZIS/CN-10 sample (C₃N₄ to ZnIn₂S₄ mass ratio of 10%) achieves the highest photocatalytic H₂O₂ production rate of 825.8 μmol g⁻¹ h⁻¹. This work provides new insights and theoretical guidance for the rational design of efficient and stable ZnIn₂S₄-based photocatalysts. Full article

Waterborne poly(vinyl alcohol) (PVA) adhesives are widely used in iodine-based polarizers, owing to their excellent transparency and interfacial adhesion. However, the intrinsic hydrophilicity of PVA compromises the long-term durability of polarizers under humid conditions. Herein, graphene derivatives with tunable oxygen contents and graphitization degrees, including graphene oxide (GO), partially reduced graphene oxide (rGO), and graphene nanosheets (GNs), were incorporated into a PVA/PEI adhesive system to investigate the oxygen-content-dependent interfacial interactions and moisture-barrier mechanisms. Structural analyses reveal that oxygen-rich GO enhances interfacial hydrogen bonding and polymer–graphene interactions, whereas highly graphitized GN primarily functions through its intrinsic lamellar barrier effect by increasing diffusion tortuosity and reducing water affinity. The rGO exhibits a compromise between interfacial interactions and barrier effects due to its moderate oxygen content and preserved graphene structure. Among them, the GN-modified adhesive demonstrates the most favorable overall performances, achieving a 14.71% reduction in the water vapor transmission rate (WVTR) of the assembled polarizer, enhanced moisture resistance, and improved antistatic capability while maintaining acceptable optical transparency. Furthermore, practical polarizer evaluations confirm that GN effectively suppresses moisture penetration, with only slight bubbling observed after 8 days of water immersion and no delamination or polarization degradation during a 40-day immersion test. These findings provide insights into the relationship between graphene oxygen content, interfacial interactions, and moisture-barrier behavior, offering an effective strategy for designing durable multifunctional waterborne adhesives for advanced optoelectronic polarizer applications. Full article

Recent years have witnessed a surge in the research of memristors as fundamental building blocks for neuromorphic computing, owing to their exceptional ability to emulate the plastic behavior of biological synapses in a high-density, low-power hardware format. These devices are increasingly recognized as the key to achieving efficient artificial neural networks. Two-dimensional (2D) molybdenum disulfide (MoS₂) is a premier candidate for artificial synapses due to its atomic scale and tunable electronic properties. However, achieving wafer-scale MoS₂ thin films for integrated memristor systems remains a significant challenge. In this work, a scalable strategy combining cetyltrimethylammonium bromide (CTAB)-assisted electrochemical intercalation and oil–water interface self-assembly was developed to fabricate large-area 2H-phase MoS₂ thin films. Leveraging the amphiphilic nature of CTAB-functionalized MoS₂ nanosheets, continuous Janus-structured MoS₂ films with asymmetric wetting properties (hydrophilic vs. hydrophobic) were successfully prepared. Vertical-structured Ag/Janus-structured MoS₂/ITO memristors demonstrated robust non-volatile switching with high endurance and long-term retention. The devices successfully emulated biological synaptic behaviors, including short-term and long-term plasticity. Furthermore, the memristors exhibited distinct optoelectronic synergistic modulation under 405 nm illumination, enabling light-sensitive synaptic functions. This work offers a versatile interface engineering route for low-power integrated sensing–memory–computing hardware. Full article

The sustainable bio-activated carbon platelets were synthesized from tamarind (tamarind indicia) fruit seed shells (TFSs) by a pyrolysis approach with an inert gas atmosphere. The carbonization process was carried out at 800 °C under an inert argon atmosphere, yielding both pure TFS-AC and chemically activated TFS-AC (KOH) carbon materials. Microscopic surface morphological analysis confirmed the formation of thin, interconnected porous carbon platelet nanosheets with enhanced surface structural uniformity. Raman spectroscopy revealed characteristic D- and G-bands, signifying the presence of graphitic domains and partial structural disorder. BET surface area analysis indicated a significant improvement from 48.54 m²/g in TFS-AC to 124.72 m²/g in TFS-AC (KOH), suggesting enhanced pore development and surface accessibility due to KOH activation. Electrochemical two-electrode performance was evaluated in symmetric device configurations using 3M KOH aqueous electrolyte. The TFS-AC (KOH) device exhibited a remarkable specific capacitance, which delivered 129.03 F/g at 0.5A/g, compared to the pure TFS-AC device. Electrochemical impedance spectroscopy (EIS) further confirmed low internal resistance and favorable ion transport. These findings confirm that KOH-activated TFS-derived carbon nanosheets have higher electrochemical stability, retaining 98.2% capacitance over 10,000 cycles. These results are promising electrode materials for high-performance supercapacitor applications, owing to their superior electrochemical symmetric device performance of bio-mass carbon Tamarind seed shell platelet nanosheets for future energy storage symmetric device applications. Full article

The unique contributions of 2D Ti₃C₂ MXenes surface, electrical, and chemical features play a crucial role in determining toxic and flammable gas-sensing behavior. Specifically, its high electrical conductivity (metallic nature), layered nanosheet structure (nanosheets), and surface termination groups (–O, –F, and –OH) collectively contribute to excellent hydrogen (H₂) and ammonia (NH₃) gas-sensing behavior. This review systematically explores the impact of pristine and modified Ti₃C₂ MXene, including its interfaces with various metals and metal oxides for enhancing H₂ and NH₃ detection. Furthermore, the significance of room temperature operation and flexible gas sensing mechanisms is explored. Notably, integration of Ti₃C₂ MXene and sulfur nanosheets demonstrates rapid response and recovery times with detection limits at ppt level. Ti₃C₂ MXene-based interfaces also exhibit excellent long-term stability under various relative humidity conditions. The selective surface termination groups (–OH and –O) facilitate the formation of hydrogen bonds with NH₃ molecules for enhancing gas adsorption and sensing selectivity. In addition, the expansion of the interlayer spacing plays a vital role in improving the gas-sensing performance. Partial oxidation of Ti₃C₂ MXene into TiO₂ increases the interlayer distance, promoting faster diffusion of gas molecules and quicker sensor response. Overall, the intrinsic properties of Ti₃C₂ MXene and its composites significantly achieve high-performance room-temperature H₂ and NH₃ gas-sensing performance. Full article

Bismuth oxybromide (BiOBr), a layered semiconductor with good photogenerated carrier separation, is valuable for visible-light organic pollutant degradation. However, traditional hydrolysis-synthesized BiOBr has uneven particles, agglomeration, and insufficient active sites, limiting performance. This study used a microwave–hydrothermal method (adjusting time, temperature, power, pH) to prepare nanosheet-assembled BiOBr, characterized via XRD, SEM, Raman, and XPS. Under light irradiation, BiOBr primarily degrades Rhodamine B through direct oxidation by highly oxidative photogenerated holes, supplemented by the auxiliary oxidation of superoxide radicals. While maintaining a consistent catalyst loading, the optimal experimental conditions were applied (140 °C, 400 W, 10 min); 50–60 nm thick BiOBr achieved 95.4% RhB degradation (k = 0.03174 min⁻¹) in 100 min, far better than traditional BiOBr (61.16%, k = 0.00917 min⁻¹). This proves the method optimizes BiOBr performance. Full article

A convenient one-pot strategy was adopted to fabricate Cu-4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) nanosheets through the coordination of HEPES with copper ions under alkaline conditions, and the obtained nanosheets possessed dual laccase-mimetic and oxidase-mimetic activities for phenolic pollutant analysis and show potential for dye decolorization/removal. The Cu-HEPES nanosheets displayed significant dual enzyme-mimetic activities, effectively catalyzing the oxidation conversion for phenolic compounds, specifically 2,4-dichlorophenol (2,4-DCP), to yield quinone imine products characterized by a unique absorption signal at 500 nm. Meanwhile, Cu-HEPES nanosheets also facilitated the conversion of 3,3′,5,5′-tetramethylbenzidine to yield a yellow-green substance with a distinctive absorption signal at 458 nm. The Cu-HEPES nanosheets displayed a satisfactory affinity (K_m = 23.2 μM) for 2,4-DCP, facilitating its use in accurately detecting 2,4-DCP (linear range from 3.3 to 16.6 µM) with a detection limit of 0.3 µM. Subsequently, the devised colorimetric sensing platform was applied to measure 2,4-DCP levels in real tap water samples, yielding satisfactory spiked recoveries ranging from 92.7% to 106.9%. Finally, the synthesized Cu-HEPES nanosheets were preliminarily evaluated for the simultaneous decolorization/removal of malachite green and Congo red, suggesting their potential applicability in aqueous systems containing multiple organic dyes. Full article

Excessive fluoride in groundwater and industrial wastewater poses serious risks to human health. Although commercial γ-alumina is a low-cost adsorbent recommended for defluoridation, its limited adsorption capacity and poor regeneration stability hinder its practical application. In this work, three template-free γ-alumina materials with distinct morphologies (nanosheets, rhombic flakes, and nanofibers) were synthesized by a mild hydrothermal method and systematically compared with commercial granular γ-alumina. To isolate the effect of morphology, all four γ-alumina adsorbents were prepared with comparable BET surface areas (180–230 m²·g⁻¹). Their structural, morphological, and surface properties were comprehensively characterized, and their fluoride adsorption performance, adsorption mechanism, and regeneration behavior were systematically evaluated. Despite their similar BET surface areas, the four samples exhibited markedly different adsorption performances. At an initial fluoride concentration of 600 mg·L⁻¹, the adsorption capacity followed the order: nanosheets (87.2 mg·g⁻¹) > nanofibers (49.0 mg·g⁻¹) > rhombic flakes (46.1 mg·g⁻¹) > commercial alumina (35.0 mg·g⁻¹). The superior adsorption performance of the nanosheet morphology suggests that the accessibility and local chemical environment of surface hydroxyl species, rather than their total abundance alone, play an important role in fluoride adsorption. In contrast, nanofibrous XW-600 exhibited superior resistance to repeated acid–alkali regeneration, preserving its crystal structure and fibrous morphology while maintaining the highest residual adsorption capacity among the synthesized alumina samples after five regeneration cycles. Overall, the results suggest that alumina morphology strongly influences fluoride adsorption performance and regeneration stability. This work provides a simple, template-free strategy for preparing morphology-controlled γ-alumina and offers new insights into the relationship between alumina morphology and fluoride adsorption, providing guidance for the rational design of high-performance, regenerable alumina adsorbents. Full article

Flexible electronics require thermal-management materials that can efficiently dissipate heat while maintaining mechanical compliance under deformation. In this study, a topology-optimized kirigami BNNS/PVA composite film was developed by combining boron nitride nanosheet incorporation, electrospinning, and thermo-mechanical topology optimization. The electrospun BNNS/PVA network enhanced the in-plane thermal conductivity from 0.19 to 4.63 W/(m·K), while the optimized kirigami architecture improved deformation accommodation by reducing elastic strain energy accumulation. The average temperature and total elastic strain energy were reduced from 86 °C to 53 °C and from 43 J to 11 J, respectively. The optimized structure achieved a maximum stress of 2.39 MPa and a maximum strain of 5.02% and reduced the steady-state temperature by up to 21.27 °C under identical heating conditions. Furthermore, in-plane thermal conductivity was maintained after 300 bending cycles, which provides an effective material–structure design strategy for flexible electronic thermal management applications. Full article

Van der Waals indium selenide is a promising material for next-generation optoelectronics due to its thickness-dependent band structure and high carrier mobility. Here, we investigate the optical properties of size-selected liquid-phase exfoliated γ-InSe nanosheets. The dispersions, composed of flakes with lateral dimensions below 100 nm, exhibit pronounced structural disorder and size-dependent optical behavior. Absorbance spectroscopy reveals systematic changes across size-selected fractions, enabling the extraction of quantitative metrics for estimating nanosheet lateral size and layers number. In addition, stability studies demonstrate significant degradation under ambient conditions, which is accelerated at elevated temperatures. Photoluminescence measurements on nanosheets exfoliated under inert conditions show broad, asymmetric emission with a clear blue-shift for smaller flakes, reflecting quantum confinement and dielectric screening effects. The emission characteristics further indicate a dominant contribution from localized states associated with disorder. These findings provide insight into the structure–property relationships in liquid-phase exfoliated γ-InSe and highlight its potential for solution-processed optoelectronic applications. Full article

Ruthenium-based catalysts have attracted considerable attention owing to their excellent activity in the selective hydrogenation of benzene to cyclohexene. Their catalytic performance is primarily governed by the electronic structure of metallic active sites and the interfacial interaction between the metal and the support. In this work, three types of TiO₂ support, including nanosheet flowers (TNSFs), elongated bipyramids (TNEBs), and tetragonal bipyramids (TNQBs), were successfully synthesized via a solvothermal route, which predominantly expose the (001), (010), and (101) crystal facets, respectively. Subsequently, ruthenium nanoparticles were deposited onto the support surfaces by means of chemical reduction, yielding three supported catalysts. The exposed (101) crystal facets of TNQBs induce the strongest electronic metal–support interaction (EMSI). Abundant Ti³⁺ defects and oxygen-containing species on the surface endow the catalyst with superior hydrophilicity, enhancing the contact between the reaction medium and active sites as well as the desorption of cyclohexene. Meanwhile, the supported Ru species exhibit the highest fraction of electron-deficient states, with the proportion of Ru^β reaching up to 82.22%. As a result, the catalyst exhibits outstanding catalytic performance, achieving a benzene conversion of 42.8%, a cyclohexene selectivity of 82.27%, and a cyclohexene yield as high as 53.22%. Full article

Ce-modified MnCo₂O₄ flower-like nanosheet electrodes were prepared on nickel foam by a hydrothermal-calcination route and sequentially optimized with respect to reaction time, nominal Ce content, and PVP addition. Comparative SEM, XRD, XPS, and N₂-sorption analyses identify MnCo₂O₄-9 h-3%Ce-PVP as the optimized electrode, with an open hierarchical nanosheet network and a BET surface area of 210.0 m² g⁻¹. The direct XRD/XPS control comparison distinguishes Ce-associated lattice and surface-state changes from PVP-associated synthesis effects without treating either trend as proof of substitutional Ce occupancy or quantitatively established oxygen vacancies. Likewise, PVP is treated as a morphology-directing additive whose transient adsorption or bridging role remains a synthesis hypothesis rather than a directly verified molecular mechanism. The optimized positive electrode delivers 2008 F g⁻¹ at 1 A g⁻¹, retains 1227 F g⁻¹ at 20 A g⁻¹, and shows 99.0% capacitance retention after 10,000 cycles at 5 A g⁻¹. A carbon-supported iron oxide negative electrode, designated C/Fe₂O₃ only as a sample label because its exact oxide phase was not independently resolved by XRD or Raman spectroscopy, provides 443 F g⁻¹ at 1 A g⁻¹. The resulting charge-balanced asymmetric device operates over 0–1.6 V and delivers 34.6 F g⁻¹ at 1 A g⁻¹, corresponding to 12.30 Wh kg⁻¹ at 0.8 kW kg⁻¹. At 10 A g⁻¹, it retains 29.8 F g⁻¹ and delivers 10.60 Wh kg⁻¹ at 8.0 kW kg⁻¹, equivalent to 86.1% capacitance retention over a tenfold increase in current density. All device-level gravimetric values are calculated using the total active mass of both electrodes. Full article

Rapid and matrix–aware evaluation of antioxidant responses in dairy–containing tea beverages remains challenging because milk components may interfere with the detectable activity of tea polyphenols. In this study, a photoactivated Mn–doped carbon nanosheet (Mn–CNS)–based dual–mode nanozyme assay was developed for the rapid evaluation of antioxidant responses in tea beverages and dairy tea matrices. The Mn–CNSs exhibited light–triggered oxidase–like activity toward 3,3′,5,5′–tetramethylbenzidine, enabling synchronized colorimetric and fluorescence readouts within 1 min. Using epigallocatechin gallate as a model antioxidant, the assay showed limits of detection of 0.22 and 0.29 μg/mL in the colorimetric and fluorescence modes, respectively, together with good selectivity and applicability to tea infusions. When applied to milk tea systems, the measurable antioxidant response decreased to 56.9–72.2% of that in corresponding tea infusions, indicating a pronounced matrix–dependent attenuation. Matrix–matched calibration and dual–indicator recovery analysis further distinguished tea infusion recovery from antioxidant response recovery, while molecular docking suggested that β–lactoglobulin–EGCG interactions contributed to the reduced detectable response. These results demonstrate that the proposed dual–mode assay is a rapid tool for antioxidant–response evaluation and highlight the importance of matrix–aware interpretation in complex dairy tea beverages. Full article