Nanomaterials最新文献

Semiconductor polymeric graphitic carbon nitride (g-C₃N₄) photocatalysts have garnered significant and rapidly increasing interest in the realm of visible light-driven hydrogen evolution reactions. This interest stems from their straightforward synthesis, ease of functionalization, appealing electronic band structure, high physicochemical and thermal stability, and robust photocatalytic activity. This review starts with the basic principle of photocatalysis and the development history, synthetic strategy, and structural properties of g-C₃N₄ materials, followed by the rational design and engineering of g-C₃N₄ from the perspectives of nano-morphological control and electronic band tailoring. Some representative results, including experimental and theoretical calculations, are listed to show the advantages of optimizing the above two characteristics for performance improvement in photocatalytic hydrogen evolution from water splitting. The existing opportunities and challenges of g-C₃N₄ photocatalysts are outlined to illuminate the developmental trajectory of this field. This paper provides guidance for the preparation of g-C₃N₄ and to better understand the current state of the art for future research directions.

Non-enzymatic glucose detection is an effective strategy to control the blood glucose level of diabetic patients. A novel hierarchical core-shell structure of nickel hydroxide shell coated copper hydroxide core based on copper foam (Ni(OH)₂@Cu(OH)₂-CF) was fabricated and derived from NiO@Cu₂O-CF for glucose sensing. Cyclic voltammetry and amperometry experiments have demonstrated the efficient electrochemical catalysis of glucose under alkaline conditions. The measurement displays that the fabricated sensor exhibits a detection scale of 0.005-4.5 mM with a detection sensitivity of 4.67 µA/µM/cm². It has remarkable response/recovery times in respect of 750 μM glucose (1.0 s/3.5 s). Moreover, the NiO@Cu₂O-CF shows significant selectivity, reliable reproducibility and long-term stability for glucose determination, suggesting it is a suitable candidate for further applications.

High-performance lightweight materials are urgently needed because of energy savings and emission reduction. Here, we design a new steel with a low density of 6.41 g/cm³, which is a 20% weight reduction compared to the conventional steel. The mechanical properties and microstructures of the steels prepared with different routes are systematically explored by utilizing uniaxial tensile testing and transmission electron microscopy. The steel processed by cold rolling and recrystallization annealing at 950 °C for 15 min shows an ultra-high yield strength of 1241 ± 10 MPa, while retaining a good ductility of 38 ± 1%. The high yield strength is mainly related to the synergistic precipitation strengthening introduced by nanoscale B2 and κ'-carbides. It is encouraging to notice that the yield strength increased without scarifying ductility, compared to the ST steel. The key reason is that the high strain hardening rate is activated by combined factors, including the blockage of numerous twins and nanoscale B2 to the dislocation movements, and dynamic slip band refinement. This study is instructive for concurrently enhancing the strength and ductility of austenitic lightweight steels with fully recrystallized grains and dual nano-precipitates.

Nanoparticles are essential for energy storage, catalysis, and medical applications, emphasizing their accurate chemical characterization. However, atom probe tomography (APT) of nanoparticles sandwiched at the interface between an encapsulating film and a substrate poses difficulties. Poor adhesion at the film-substrate interface can cause specimen fracture during APT, while impurities may introduce additional peaks in the mass spectra. We demonstrate preparing APT specimens with strong adhesion between nanoparticles and film/substrate matrices for successful analysis. Copper nanoparticles were encapsulated at the interface between nickel film and cobalt substrate using electrodeposition. Cobalt and nickel were chosen to match their evaporation fields with copper, minimizing peak overlaps and aiding nanoparticle localization. Copper nanoparticles were deposited via magnetron sputter inert gas condensation with varying deposition times to yield suitable surface coverages, followed by encapsulation with the nickel film. In-plane and cross-plane APT specimens were prepared by femtosecond laser ablation and focused ion beam milling. Longer deposition times resulted in agglomerated nanoparticles as well as pores and voids, causing poor adhesion and specimen failure. In contrast, shorter deposition times provided sufficient surface coverage, ensuring strong adhesion and reducing void formation. This study emphasizes controlled surface coverage for reliable APT analysis, offering insights into nanoparticle chemistry.

The design and preparation of advanced hybrid nanofibers with controllable microstructures will be interesting because of their potential high-efficiency applications in the environmental and energy domains. In this paper, a simple and efficient strategy was developed for preparing hybrid nanofibers of zinc oxide-molybdenum disulfide (ZnO-MoS₂) grown on polyimide (PI) nanofibers by combining electrospinning, a high-pressure hydrothermal process, and in situ growth. Unlike simple composite nanoparticles, the structure is shown in PI-ZnO to be like the skeleton of a tree for the growth of MoS₂ "leaves" as macro-materials with controlled microstructures. The surface morphology, structure, composition, and photocatalytic properties of these structures were characterized using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV-vis spectroscopy. The ultra high-volume fraction of MoS₂ can be grown on the brush-shaped PI-ZnO. Decorating ZnO with nanosheets of MoS₂ (a transition metal dichalcogenide with a relatively narrow band gap) is a promising way to increase the photocatalytic activity of ZnO. The hybrid nanofibers exhibited high photocatalytic properties, which decomposed about 92% of the methylene blue in 90 min under visible light irradiation. The combination of MoS₂ and ZnO with more abundant surface-active sites significantly increases the spectral absorption range, promotes the separation and migration of carriers, and improves the photocatalytic characteristics.

(1) Background: The widespread use of nanoparticles (NPs) implies their inevitable contact with living organisms, including aquatic microorganisms, making it essential to understand the effects and consequences of this interaction. Understanding the adaptive responses and biochemical changes in microalgae and cyanobacteria under NP-induced stress is essential for developing biotechnological strategies that optimize biomolecule production while minimizing potential toxicity. This study aimed to evaluate the interactions between various potentially toxic nanoparticles and the cyanobacterial strain Arthrospira platensis, focusing on the biological adaptations and biochemical mechanisms that enable the organism to withstand xenobiotic exposure. (2) Methods: The cyanobacterium Arthrospira platensis CNMN-CB-02 was cultivated under optimal laboratory conditions in the presence of CuNPs, CuONPs, ZnONPs, and TiO₂NPs. Biochemical analyses were performed on the collected biomass. (3) Results: Various interactions between nanoparticles (NPs) and the cyanobacterial culture were identified, ranging from hormetic effects at low concentrations to evident toxic effects at high concentrations. NP toxicity was observed through the reduction in photosynthetic pigments and the disappearance of phycobiliproteins. Notably, NP toxicity was not always accompanied by increased malondialdehyde (MDA) levels. (4) Conclusions: Arthrospira platensis exhibits unique adaptive mechanisms under NP-induced stress, offering the potential for controlled NP applications in biotechnology. Future research should further explore the relationship between nanoparticle types and cyanobacterial responses to optimize biomolecule production.

Solid-state electrolytes for lithium-ion batteries, which enable a significant increase in storage capacity, are at the forefront of alternative energy storage systems due to their attractive properties such as wide electrochemical stability window, relatively superior contact stability against Li metal, inherently dendrite inhibition, and a wide range of temperature functionality. NASICON-type solid electrolytes are an exciting candidate within ceramic electrolytes due to their high ionic conductivity and low moisture sensitivity, making them a prime candidate for pure oxidic and hybrid ceramic-in-polymer composite electrolytes. Here, we report on producing pure and Y-doped Lithium Aluminum Titanium Phosphate (LATP) nanoparticles by spray-flame synthesis. The as-synthesized samples consist of an amorphous component and anatase-TiO₂ crystalline particles. Brief annealing at 750-1000 °C for one hour was sufficient to achieve the desired phase while maintaining the material's sub-micrometer scale. Rietveld analysis of X-Ray diffraction data demonstrated that the crystal volume increases with Y doping. At the same time, with high Y incorporation, a segregation of the YPO₄ phase was observed in addition to the desired LATP phase. Another impurity phase, LiTiOPO₄, was observed besides YPO₄ and, with higher calcination temperature (1000 °C), the phase fraction for both impurities also increased. The ionic conductivity increased with Y incorporation from 0.1 mS/cm at room temperature in the undoped sample to 0.84 mS/cm in the case of LAY0.1TP, which makes these materials-especially considering the comparatively low sintering temperature-highly interesting for applications in the field of solid-state batteries.

Understanding the interplay between the molecular structure of the ionic liquid (IL) subunit, the resulting nanostructure and ion transport in polymerized ionic liquids (PILs) is necessary for the realization of high-performance solid-state electrolytes required in various advanced applications. Herein, we present a detailed structural characterization of a recently synthesized series of acrylate-based PIL homopolymers and networks with imidazolium cations and chloride anions with varying alkyl spacer and terminal group lengths designed for organic solid-state batteries based on X-ray scattering. The impact of the concentrations of both the crosslinker and added tetrabutylammonium chloride (TBACl) conducting salt on the structural characteristics is also investigated. The results reveal that the length of both the spacer and terminal group influence the chain packing and, in turn, the nanophase segregation of the polar domains. Long spacers and terminal groups seem to induce denser polar aggregates sandwiched between more compact alkyl spacer and terminal group domains. However, the large inter-backbone spacing achieved seems to limit the ionic conductivity of these PILs. More importantly, our findings show that the previously reported general relationships between the ionic conductivity and the structural parameters of the nanostructure of PILs are not always attainable for different molecular structures of the IL side group.

Laser conversion of commercial polymers to laser-induced graphene (LIG) using inexpensive and accessible CO₂ lasers has enabled the rapid prototyping of promising electronic and electrochemical devices. Frequently used to pattern interdigitated supercapacitors, few approaches have been developed to pattern batteries-in particular, full cells. Herein, we report an LIG-based approach to a planar, interdigitated Li-S battery. We show that sulfur can be deposited by selective nucleation and growth on the LIG cathode fingers in a supersaturated sulfur solution. Melt imbibition then leads to loadings as high as 3.9 mg/cm² and 75 wt% sulfur. Lithium metal anodes are electrodeposited onto the LIG anode fingers by a silver-seeded, pulse-reverse-pulse method that enables loadings up to 10.5 mAh/cm² to be deposited without short-circuiting the interdigitated structure. The resulting binder/separator-free flexible battery achieves a capacity of over 1 mAh/cm² and an energy density of 200 mWh/cm³. Unfortunately, due to the use of near stoichiometric lithium, the cycle-life is sensitive to lithium degradation. While future work will be necessary to make this a practical, flexible battery, the interdigitated structure is well-suited to future operando and ex situ studies of Li-S and related battery chemistries.

Hypoxia, a phenomenon that occurs when the oxygen level in tissues is lower than average, is commonly observed in human solid tumors. For oncological treatment, the hypoxic environment often results in radioresistance and chemoresistance. In this study, a new multifunctional oxygen carrier, carboxymethyl hexanoyl chitosan (CHC) nanodroplets decorated with perfluorohexane (PFH) and superparamagnetic iron oxide (SPIO) nanodroplets (SPIO@PFH-CHC), was developed and investigated. PFH-based oxygen carriers can augment oxygenation within tumor tissues, thereby mitigating radioresistance. Concurrently, oxygenation can cause deoxyribonucleic acid (DNA) damage via oxygen fixation and consequently suppress cancer cell proliferation. Moreover, these pH-sensitive nanodroplets allow higher cellular uptake with minimal cytotoxicity. Two distinctive mechanisms of SPIO@PFH-CHC nanodroplets were found in this study. The SPIO nanoparticles of the SPIO@PFH-CHC nanodroplets can generate hydroxyl radicals (HO^•) and other reactive oxygen species (ROS), which is vital to chemodynamic therapy (CDT) via the Fenton reaction. Meanwhile, the higher X-ray absorption among these nanodroplets leads to a local energy surge and causes more extensive deoxyribonucleic acid (DNA) damage via oxygen fixation. This study demonstrates that low cytotoxic SPIO@PFH-CHC nanodroplets can be an efficient radiosensitizer for radiation therapy.