ChemNanoMat最新文献

Herein, a [thermochromic microcapsules-45°C (TCM-45)/polystyrene (PS)]&[CoFe₂O₄/PS] up-down structured thermochromic-magnetic bifunctional Janus fibrous film (shorted as TMJF) is prepared by a two-step uniaxial electrospinning technique. The up-layer of TMJF is TCM-45/PS fibrous film (denoted as U-TMJF, i.e., thermochromism layer); the down-layer of TMJF is CoFe₂O₄/PS fibrous film (named as D-TMJF, i.e., magnetism layer). Due to the up-down macro Janus partition structure of TMJF, thermochromic substance (TCM-45) and magnetic substance (CoFe₂O₄) are separated from each other, which fully ensures that the dark-colored CoFe₂O₄ has no effect on the thermochromic performance of TCM-45. When the temperature augments to 45°C, the U-TMJF color rapidly transforms from blue to white. The film exhibits a more obvious color transition than the counterpart single-layer blending composite fibrous film. Moreover, due to the advantages of electrospinning, TCM-45 is completely wrapped in the microfiber, so TMJF still maintains stable thermochromic performance after ultrasonic washing for 100 min. In addition, the saturation magnetization of TMJF varies with the CoFe₂O₄ NPs content, showing tunable magnetic properties. This simple and particular macro partition design concept lays a theoretical foundation and offers technical support for the fabrication of other functionalized Janus thermochromic flexible fibrous films.

Lactic acid, a key platform chemical derived from renewable glycerol (a major byproduct of biodiesel production), holds great potential for the sustainable synthesis of high-value chemicals such as pyruvic acid. An efficient catalytic process for the oxidative dehydrogenation of glycerol-derived lactic acid by metal oxides is studied. A series of metal oxides was prepared, and their performance in the aerobic conversion of lactic acid was evaluated. During the performance evaluation, a strong crystal phase effect of MoO₃ was observed, with α-MoO₃ (orthorhombic phase) and h-MoO₃ (hexagonal phase) exhibiting significant differences in catalytic activity and selectivity. Specifically, α-MoO₃ showed a lactic acid conversion rate of only 52.3% and a pyruvic acid selectivity of 41.8%, while h-MoO₃ demonstrated superior catalytic performance. The optimal catalyst is h-MoO₃, with a lactic acid conversion rate of 81.6% and a pyruvic acid selectivity of 63.7%. Furthermore, the catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption. XRD and FTIR revealed the transformation from α-MoO₃ to h-MoO₃, while XPS demonstrated the influence of crystal phase on the catalyst's oxidative capability.

Microencapsulated phase change materials (MPCMs) with excellent photothermal conversion performance are prepared via in situ polymerization method, whose core material and shell material are n-hexadecane and graphene oxide (GO) modified melamine formaldehyde (MF), respectively. The concern here is how the GO affects the properties of prepared microcapsules for morphology, thermal properties, and photothermal conversion. The prepared n-hexadecane@MF/GO MPCMs possess preferable sphericity and well-defined core–shell structure. The prepared MPCMs exhibit excellent thermal energy storage capacity. Adding GO can effectively improve latent heat and encapsulation efficiency. The MPCMs with 0.1 wt% GO have the best latent heat of 169.12 J g⁻¹ and the highest encapsulation efficiency of 74.54%. Due to the promoted optical response in visible light and near-infrared-light of GO, photothermal conversion efficiencies of modified MPCMs are obviously raised above 40%. As the GO proportion is 0.3 wt%, the modified MPCMs reache the maximum photothermal conversion efficiency of 88.04%, 64.47% higher than unmodified MPCMs.

Over the past two decades, two-dimensional (2D) materials have garnered significant attention in both academic research and real-world applications. Among these, 2D metal–organic framework (MOF) nanosheets stand out due to their remarkable structural tunability, ultrathin layered architectures, high surface area, accessible metal nodes, soft crystallinity, and anisotropic structural arrangements. These distinctive features make 2D MOF nanosheets highly promising candidates for a variety of advanced applications, including proton-conducting electrolytes for fuel cells, selective sensing and molecular recognition, and the separation of diverse molecules—from small organic pollutants and metal ions to large biomolecules such as DNA. Despite their considerable potential, a substantial gap remains between laboratory-scale research and industrial-scale implementation. This gap is primarily attributed to challenges such as limited scalability, high production costs, stability concerns, and the pronounced stacking tendency of 2D MOF nanosheets, which can diminish their unique properties. In this review, we aim to provide a comprehensive overview of recent advances in the structural understanding, synthetic strategies, nanosheet formation processes, and stacking behaviors of 2D MOF nanosheets. We further discuss their applications as proton-conducting materials in proton-exchange membrane fuel cells (PEMFCs), as well as their roles in sensing, recognition, and molecular separation. By elucidating the structure–property relationships, particularly the influence of secondary building units (SBUs) on nanosheet morphology and performance, we seek to bridge the gap between fundamental research and practical, industrial utilization of these promising materials.

Optimizing the internal morphology of cathode materials is essential for enhancing lithium-ion battery performance by improving ion diffusion, electrical conductivity, and structural stability. This study introduces a novel high-content analysis approach to optimize cathode materials for lithium-ion batteries, focusing on internal morphology's role in performance. By combining resin-embedding cross-sectional preparation with high-throughput imaging, this method enables efficient, large-scale analysis of particle morphology, overcoming limitations in the representativeness of the observational domain. This approach allows for the rapid extraction of key features like pore size, 2D porosity, and particle uniformity, providing statistically robust insights into how synthesis conditions affect material properties. The versatility of the advanced approach for multimodal analysis, such as X-ray diffraction, atomic force microscopy, and energy-dispersive X-ray spectroscopy, highlights its potential for broad applications. This work demonstrates a significant advance in the systematic characterization and optimization of energy materials, offering a pathway for improving battery performance through tailored material design.

This study presents a facile synthesis of carbon-supported binarypalladium-copper (Pd-Cu/C) nanomaterials designed to achieve competitive catalytic activity while reducing material costs in solid polymer electrolyte (SPE) fuel cells. A surfactant-free, microwave-heated polyol process is employed to synthesize Pd/C and Pd-Cu/C nanomaterials with mean particle size below 4.0 nm. The electrocatalytic activity toward oxygen reduction reaction (ORR) and the corresponding kinetic parameters of Pd-Cu/C electrodes with varying compositions are systematically interrogated using rotating disk electrode (RDE) measurements. Notably, Tafel analysis reveals a slope of 60 ± 2 mV per decade slope at low current densities indicating that the first electron transfer to molecular oxygen (O₂) is the rate-determining step. At higher current densities, a slope of 144 ± 8 mV per decade suggests a transition proton-coupled electron transfer as the dominant mechanism. Furthermore, electrochemical performance of membrane-electrode-assemblies (MEAs) reveals a peak power density of ∼ 475 mW cm⁻² with Pd /C cathode under optimal operating conditions. However, increasing the Cu content in the Pd-Cu/C catalysts results in a marked decrease in current density, likely due to partial Cu dissolution. These findings highlight the potential of binary Pd-Cu nanomaterials as promising alternatives to platinum-based catalysts for Pt-free SPE fuel cell applications.

Developing highly active and durable electrocatalysts for oxygen reduction reaction (ORR) is critical for the widespread use of next-generation power sources, such as proton exchange membrane fuel cells. Herein, we report the synthesis of 1D AuAg@Pt core–shell nanowires (AuAg@Pt NWs) as an advanced ORR catalyst. A unique feature of this catalyst is a significant counterintuitive compressive strain applied to its Pt shell, which can be attributed to the high density of grain boundaries in the AuAg NW core. This strain can induce a downward shift of the Pt d-band center, leading to an optimized binding energy for oxygen species. Consequently, the prepared AuAg@Pt NWs exhibited enhanced ORR activity compared to core–shell nanorods with a low density of grain boundaries and a commercial Pt/C catalyst. Furthermore, they showed outstanding durability for repeated ORR operation due to their 1D wire structure that can effectively protect them against particle agglomeration. This work highlights a rational design strategy that combines electronic and morphological engineering to devise advanced, stable electrocatalysts.

Driven by the global energy structure transition, new energy vehicles and large-scale energy storage devices are exhibiting a rapid development trend, which also presents more rigorous performance requirements for lithium-ion batteries (LIBs) in terms of energy density, cycle life, and safety performance. LiMn_xFe_1-xPO₄ (LMFP) has become a hot research object owing to its wide voltage working range, excellent thermodynamic stability, and other characteristics. However, the poor electronic conductivity, slow Li⁺ diffusion rate, and insufficient utilization rate of high-voltage plateaus limit its commercial application. In this article, the nanoscale LiMn_0.5Fe_0.5PO₄ (LMFP55) cathode material was synthesized by a method combining mechanochemical ball milling with high-temperature solid-state calcination. Then, the LMFP cathode materials modified with different zirconium dioxide (ZrO₂) coating amounts were prepared by the ionic liquid-assisted solid-phase method. The effect of coating content on the structure and electrochemical performance of the materials was investigated. We found that the LMFP coated with 3 wt% ZrO₂ has optimal performance of retention ratio up to 96.01% after 200 cycles at 0.1C, significantly improving the long-life cycle performance and interface stability of the material. This article provides an effective approach for optimizing LIBs and advancing their development.

The interband (d → sp) transition in the Au nanostructures of the CeO₂NP/Au/CeO₂NR (CAC) heterostructure enhances its photocatalytic efficiency for degrading 4-chlorophenol (4-CP) under UV light. Optical field simulations have revealed the presence of intense near-field hotspots at the dual interfaces between Au and CeO₂, which play a critical role in augmenting the photocatalytic activity of this hybrid structure. Further, assessing the photoexcited charge carrier lifetimes has indicated excellent charge transfer efficiency at the CAC heterointerface that is ≈13 times higher than that observed at the CeO₂NP/CeO₂NR interface alone. This remarkable enhancement establishes the CAC heterostructure as a highly effective photocatalyst, achieving an impressive degradation performance of 85% for 4-CP, characterized by a pseudofirst-order rate constant of 0.014 min⁻¹. Radical scavenging experiments show that hydroxyl radicals (^•OH) are the primary reactive oxygen species responsible for the mineralization of 4-CP. Here, the d-band holes of Au serve as powerful oxidative centers that facilitate the efficient formation of ^•OH, driving the overall redox reactions. This study highlights the potential of Au–CeO₂ hybrid nanostructures for high-performance photocatalytic remediation of organic pollutants.

This study reports the synthesis and comprehensive magnetic characterization of $$ nanoparticles across a compositional spectrum (x = 0.6, 0.8, 1.0, 1.2, and 1.4) using a precisely controlled combustion reaction approach. Morphological analysis revealed well-defined single-domain nanoparticles with an average diameter of $$ nm. Magnetic characterization demonstrated that coercivity increases systematically with cobalt substitution, reaching a maximum for $$, while nonmonotonic behavior was observed around x = 0.8. Saturation magnetization reached its peak at $$. Furthermore, the magnetocrystalline anisotropy constant showed a significant increase with higher cobalt content. The ferrimagnetic to superparamagnetic transition was confirmed through both zero-field cooling–field-cooling measurements and theoretical estimations of blocking temperature, showing strong agreement across compositions. A high magnetic field ($$ 150 kOe) was required to approach saturation due to large anisotropy fields in Co-rich compositions. The $$ nanoclusters exhibit tunable magnetic properties through compositional adjustments, offering design principles for applications in permanent magnets, high-density magnetic storage, and biomedical fields.