Search Results (116)

Under elevated loading conditions, the aggregation of fillers emerges as a pivotal factor driving the degradation of separation performance in mixed matrix membranes. The two-dimensional (2D) modification of fillers, aimed at enhancing interfacial contact with polymers, has been recognized as an effective strategy to improve interphase compatibility and increase filler loading capacity. However, it is worth noting that the BET surface area of 2D fillers is typically relatively low. In this study, a two-step approach was developed. First, a “diffusion-mediated” process was combined with a solvent optimization strategy based on first-principles (DFT) calculations, achieving a 20-fold suppression in ZIF-67 nucleation-crystallization rate. This enabled the successful synthesis of a 2D amorphous nanoflower structure. Subsequently, the processing parameters were fine-tuned to enhance the specific surface area of ZIF-67 to 403 m²/g while preserving its 2D structural integrity. Ultimately, the as-prepared 2D ZIF-67 was incorporated into a hydrogenated styrene-butadiene block copolymer (SEBS) matrix to fabricate a mixed matrix membrane. Remarkably, at a filler loading of 20 wt%, the CH₄ permeability coefficient increased significantly from 11.7 barrer to 35.3 barrer, while the CH₄/N₂ selectivity was maintained at 3.21, indicating minimal interfacial defects and demonstrating the feasibility and effectiveness of the proposed methodology. Full article

Aiming to address the key challenges of poor enzyme stability, difficult recovery, and difficult synergistic optimization of catalytic efficiency in high-value conversion of biomass, this study utilizes mineralization self-assembly technology to combine laccase with Fe₃O₄@SiO₂-PMIDA-Cu²⁺ composite, constructing magnetic laccase nanoflower (MLac-NFs) materials with a porous structure and superparamagnetism. This synthetic material can efficiently catalyze the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). The characterization results indicated that MLac-NFs exhibit optimal catalytic activity (63.4 U mg⁻¹) under conditions of pH 6.0 and 40 °C, with significantly enhanced storage stability (retaining 94.26% of activity after 30 days of storage at 4 °C). Apparent kinetic analysis reveals that the substrate affinity and maximum reaction rate of MLac-NFs were increased by 38.3% and 439.6%, respectively. In the laccase–mediator system (LMS), MLac-NFs mediated by 30 mM TEMPO could achieve complete conversion of HMF to FDCA within 24 h. Moreover, due to the introduction of magnetic nanoparticles, the MLac-NFs could be recovered and reused via an external magnetic field, maintaining 53.26% of the initial FDCA yield after six cycles. Full article

Rapid screening of foodborne pathogens is critical for food safety, yet current detection techniques often suffer from low efficiency and complexity. In this study, we developed a sliding microfluidic colorimetric biosensor for the fast, sensitive, and multiplex detection of Salmonella. First, the target bacteria were specifically captured by antibody-functionalized magnetic nanoparticles in the microfluidic chip, forming magnetic bead–bacteria complexes. Then, through motor-assisted sliding of the chip, manganese dioxide (MnO₂) nanoflowers conjugated with secondary antibodies were introduced to bind the captured bacteria, generating a dual-antibody sandwich structure. Finally, a second sliding step brought the complexes into contact with a chromogenic substrate, where the MnO₂ nanoflowers catalyzed a colorimetric reaction, and the resulting signal was used to quantify the Salmonella concentration. Under optimized conditions, the biosensor achieved a detection limit of 10 CFU/mL within 20 min. In spiked pork samples, the average recovery rate of Salmonella ranged from 94.9% to 125.4%, with a coefficient of variation between 4.0% and 6.8%. By integrating mixing, separation, washing, catalysis, and detection into a single chip, this microfluidic biosensor offers a user-friendly, time-efficient, and highly sensitive platform, showing great potential for the on-site detection of foodborne pathogens. Full article

Cell-penetrating peptides offer a promising strategy for intracellular delivery; however, non-specific uptake and off-target cytotoxicity limit their clinical utility. To address these limitations, a cold atmospheric plasma-responsive delivery platform was developed in which the membrane activity of a peptide was transiently suppressed upon complexation with a DNA-based nanostructure. Upon localized plasma exposure, DNA masking was disrupted, restoring the biological functions of the peptides. Transmission electron microscopy revealed that the synthesized DNA nanoflower structures were approximately 150–250 nm in size. Structural and functional analyses confirmed that the system remained inert under physiological conditions and was rapidly activated by plasma treatment. Fluorescence recovery, cellular uptake assays, and cytotoxicity measurements demonstrated that the peptide activity could be precisely controlled in both monolayer and three-dimensional spheroid models. This externally activatable nanomaterial-based system enables the spatial and temporal regulation of peptide function without requiring biochemical triggers or permanent chemical modifications. This platform provides a modular strategy for the development of potential peptide therapeutics that require precise control of activation in complex biological environments. Full article

This review synthesized the current knowledge on the effect of TiO₂ photocatalysts on the degradation of microplastics (MPs) and nanoplastics (NPs) under visible light, highlighting the state-of-the-art techniques, main challenges, and proposed solutions for enhancing the performance of the photocatalysis technique. The synthesis of TiO₂-based photocatalysts and hybrid nanostructured TiO₂ materials, including those coupled with other semiconductor materials, is explored. Studies on TiO₂-based photocatalysts for the degradation of MPs and NPs under visible light remain limited. The degradation behavior is influenced by the composition of the TiO₂ composites and the nature of different types of MPs/NPs. Polystyrene (PS) MPs demonstrated complete degradation under visible light photocatalysis in the presence of α-Fe₂O₃ nanoflowers integrated into a TiO₂ film with a hierarchical structure. However, photocatalysis generally fails to achieve the full degradation of small plastic pollutants at the laboratory scale, and its overall effectiveness in breaking down MPs and NPs remains comparatively limited. Full article

The electrocatalytic decomposition of ammonia represents a promising route for sustainable hydrogen production, yet current systems rely heavily on noble metal catalysts with prohibitive costs and limited durability. A critical challenge lies in developing non-noble electrocatalysts that simultaneously achieve high active site exposure, optimized electronic configurations, and robust structural stability. Addressing these requirements, this study strategically engineered Cu-doped ZIF-8 architectures via in situ growth on nickel foam (NF) substrates through a facile room-temperature hydrothermal synthesis approach. Systematic optimization of the Cu/Zn molar ratio revealed that Cu_0.7Zn_0.3-ZIF/NF achieved optimal performance, exhibiting a distinctive nanoflower-like architecture that substantially increased accessible active sites. The hybrid catalyst demonstrated superior electrocatalytic performance with a current density of 124 mA cm⁻² at 1.6 V vs. RHE and a notably low Tafel slope of 30.94 mV dec⁻¹, outperforming both Zn-ZIF/NF (39.45 mV dec⁻¹) and Cu-ZIF/NF (31.39 mV dec⁻¹). Combined XPS and EDS analyses unveiled a synergistic electronic structure modulation between Zn and Cu, which facilitated charge transfer and enhanced catalytic efficiency. A gas chromatography product analysis identified H₂ and N₂ as the primary gaseous products, confirming the predominant occurrence of the ammonia oxidation reaction (AOR). This study not only presents a noble metal-free electrocatalyst with exceptional efficiency and durability for ammonia decomposition but also demonstrates the significant potential of MOF-derived materials in sustainable hydrogen production technologies. Full article

A three-dimensional Bi-enriched Bi₂O₃/Bi₂MoO₆ Z-scheme heterojunction photocatalyst was successfully synthesized via a facile one-step hydrothermal method for efficient phenol degradation under visible light. Structural and morphological characterizations (SEM, TEM, and XRD) confirmed the formation of a nanoflower-like architecture with a high specific surface area of 81.27 m²/g. Optical and electrochemical analyses revealed efficient charge separation and extended visible-light response. Under visible-light irradiation (λ > 420 nm), this heterojunction (Bi₂O₃:Bi₂MoO₆ = 3:7) demonstrated exceptional performance, degrading 97.06% of phenol (30 mg/L) within 60 min. XPS analysis confirmed the Z-scheme charge transfer mechanism: Photogenerated electrons in the conduction band of Bi₂O₃ (−0.59 eV) facilitated the generation of ·O₂⁻ radicals, while holes in the valence band of Bi₂MoO₆ (2.44 eV) predominantly produced ·OH radicals. This synergistic effect resulted in highly efficient mineralization and degradation of phenol. Full article

In this study, Bi₂MoO₆ nanoflowers with different molybdenum sources were in situ grown on the surface of g-C₃N₄ nanosheets (OCN) by a simple one-step solvothermal method. The effects of doping and different molybdenum sources on the photocatalytic degradation and bactericidal activity of Bi₂MoO₆/OCN were discussed. Among them, the solvothermal preparation of P-Bi₂MoO₆/OCN using phosphomolybdic acid as molybdenum source can make up for the shortcomings caused by the destruction of OCN structure by generating more lattice defects to promote charge separation and constructing Lewis acid/base sites to effectively improve the photocatalytic performance. In addition, by adding phosphoric acid to increase the P-doped content, more exposed alkaline active sites are induced on the surface of P-Bi₂MoO₆/OCN, as well as larger specific surface area and charge transfer efficiency, which further improve the photocatalytic performance. Finally, the optimized 16P-Bi₂MoO₆/OCN showed a degradation rate of 99.7% for 20 mg/L rhodamine B (RhB) within 80 min under visible light, and the antibacterial rates against E. coli, S. aureus and P. aeruginosa within 300 min were 99.58%, 98.20% and 97.48%, respectively. This study provides a reference for optimizing the synthesis of environmentally friendly, solar-responsive, photocatalytic sterilization materials from the perspective of preparation, raw materials and structure. Full article

A nanoflower-like nickel-molybdenum alloy was synthesized by hydrothermal in situ growth of NiMoO₄ nanorod arrays on nickel foam (NF) followed by gas-phase re-reduction at 600 °C. The resulting structure has a uniform porosity and high specific surface area, which improves the availability of active sites and facilitates efficient electron and mass transport. SEM and XPS analyses confirm that the formed NiMoO₄ nanorods are uniformly distributed, which leads to significant optimization of their electronic structure. The electrochemical measurements revealed that the sample exhibited excellent hydrogen evolution reaction (HER) performance, with an overpotential as low as 127 mV at 100 mA cm⁻² and a Tafel slope of 124 mV dec⁻¹. CV and EIS showed that the sample had the largest electrochemically active surface area (121.3 mF cm⁻²) among the samples treated at different temperatures, with the smallest charge transfer resistance. In addition, the catalyst maintained high stability after 45 h of continuous operation. These results highlight the potential of NiMo/NF as a highly efficient and durable HER catalyst to help advance hydrogen energy technology. Full article

Background/Objectives: Magnetic hyperthermia (MH) has emerged as a promising alternative to conventional cancer treatments, offering targeted tumor destruction with minimal damage to healthy tissues. In this study, we synthesized manganese-doped magnetic nanoflowers (Mn-NFs) using a polyol-mediated approach to enhance heating efficiency and biocompatibility for MH applications. Our objective was to evaluate their structural, magnetic, and in vitro hyperthermic properties to determine their potential for lung cancer therapy. Methods: Mn-NFs, with the general formula MnxFe₃-xO₄ (x = 0, 0.3, 0.5, 0.7), were synthesized via a one-step polyol method and characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Their heating efficiency was assessed through specific absorption rate (SAR) measurements in aqueous and solid environments under an alternating magnetic field (AMF). Cytocompatibility was evaluated using the Alamar Blue assay on A549 lung carcinoma cells. Cellular uptake was quantified via a colorimetric iron determination method, while in vitro MH efficacy was tested by subjecting Mn-NF-loaded A549 cells to AMF exposure at different field strengths and nanoparticle concentrations. Results: Mn-NFs exhibited a flower-like morphology with enhanced magnetic properties, achieving high SAR values, particularly in immobilized conditions. Cytotoxicity assays confirmed high biocompatibility at relevant doses, with Mn-NFs of x = 0.3 showing optimal cellular uptake. MH studies demonstrated significant cancer cell death at AMF intensities of around 30 kA/m, with increased effectiveness following static magnetic field pre-alignment. Conclusions: The results highlight Mn-NFs, particularly those with a Mn content of x = 0.3, as promising candidates for MH-based lung cancer therapy, combining high heating efficiency, biocompatibility, and effective intracellular uptake. Further studies are needed to validate their therapeutic potential in vivo. Full article

Given the pressing demand for efficient uranium (U(VI)) enrichment and its elimination from wastewater to curtail the risks of radioactive contamination inherent in nuclear energy applications, it is crucial to design materials with high removal efficiency and straightforward separation processes. In the current study, we incorporated konjac gum (KGM) into MgAl-double oxide (MgAl-LDO) and synthesized an innovative, economical, and environmentally friendly LDO-KGM material by using the freeze-drying-calcination (FDC) method, which provided a solution for U(VI) concentration from aqueous solutions. The nanoflower structures LDO-KGM with abundant pore structure and high specific surface area exhibited an optimal U(VI) adsorptive capacity (3019.56 mg·g⁻¹) at pH = 6.0 and 293 K, which was 2.3 times greater than that of MgAl-LDO (1296.39 mg·g⁻¹). LDO-KGM also showed great adaptability for the immobilization of U(VI) over a broad pH range (4.0 to 9.0) and coexisting ions. U(VI) adsorption onto LDO-KGM adhered to the pseudo-second-order kinetic model (R² ≥ 0.99) and the Langmuir isotherm model (R² ≥ 0.99). The analysis of thermodynamic parameters derived from isotherms at varying temperatures revealed that U(VI) adsorption onto LDO-KGM was an endothermic and spontaneous process. The mechanism underlying U(VI) adsorption by LDO-KGM was mainly complexation, carbonate co-precipitation, and electrostatic adsorption. Furthermore, the adsorption efficiency of LDO-KGM for U(VI) could still retain more than 84.5% after five cycles. The findings indicate that the synthesized LDO-KGM exhibits potential as an exceptionally potent adsorbent for the purification of wastewater contaminated with U(VI). Full article

Toxic and harmful gases, particularly volatile organic compounds like triethylamine, pose significant risks to human health and the environment. As a result, metal oxide semiconductor (MOS) sensors have been widely utilized in various fields, including medical diagnostics, environmental monitoring, food processing, and chemical production. Extensive research has been conducted worldwide to enhance the gas-sensing performance of MOS materials. However, traditional MOS materials suffer from limitations such as a small specific surface area and a low density of active sites, leading to poor gas sensing properties—characterized by low sensitivity and selectivity, high detection limits and operating temperatures, as well as long response and recovery times. To address these challenges in triethylamine detection, this paper reviews the synthesis of nano-microspheres, porous micro-octahedra, and hollow prism-like nanoflowers via chemical solution methods. The triethylamine sensing performance of MOS materials, such as ZnO and In₂O₃, can be significantly enhanced through nano-morphology control, electronic band engineering, and noble metal loading. Additionally, strategies, including elemental doping, oxygen vacancy modulation, and structural morphology optimization, have been employed to achieve ultra-high sensitivity in triethylamine detection. This review further explores the underlying mechanisms responsible for the improved gas sensitivity. Finally, perspectives on future research directions in triethylamine gas sensing are provided. Full article

WO₃ nanoflowers were synthesized via anodization and subsequently calcined in air at different temperatures (200–700 °C) to evaluate their photocatalytic activity. The samples were characterized in terms of their morphological, crystallite, and optical properties. Anodization produced WO₃ hydrate with a layer thickness of ~1.2 µm, which was transformed into WO₃ after heating. All samples exhibited monoclinic phase, with Raman shift intensity increasing with the calcination temperature. Some residual WO₃·H₂O was detected at certain temperatures. The calculated bandgap energy ranged from 2.49 to 2.67 eV, with higher calcination temperatures leading to lower absorbance in the UV region. The photodegradation of phenol under UV-Vis radiation reached 35% in 60 min for WO₃_700 °C, where the photocatalyst suffered a morphological transformation from a nanoflower to nanogranular structure, accompanied by increased crystallinity. Under visible light, the phenol abatement was limited, achieving 1–3% degradation. The WO₃ surface is likely negatively charged at the solution’s pH (5.6), which may explain the low phenol adsorption (~1%). Full article

Hydrogen plays a vital role in the global shift toward cleaner energy solutions, with water electrolysis standing out as one of the most promising techniques for generating hydrogen. Despite its potential, the oxygen evolution reaction (OER) involved in this process faces significant challenges, including high overpotentials and slow reaction rates, which underscore the need for advanced electrocatalytic materials to enhance efficiency. Noble metal catalysts are effective but expensive, so transition-metal-based electrocatalysts like nickel–cobalt layered double hydroxides (NiCo LDHs) have become promising alternatives. In this research, a series of NiCo LDH catalysts doped with Fe, Mn, Cu, and Zn were effectively produced using a one-step hydrothermal technique. Among the catalysts, the Fe-doped NiCo LDH exhibited OER activity, achieving a lower overpotential (289 mV) at a current density of 50 mA/cm², which was far better than the 450 mV of the undoped NiCo LDH. The Mn-, Cu-, and Zn-NiCo LDHs also exhibited lower overpotentials of 414 mV, 403 mV, and 357 mV, respectively, at this current density. The Fe-doped NiCo LDH had a 3D layered nanoflower structure, increasing the surface area for reactant adsorption. The electrochemically active surface area (ECSA), as indicated by the double-layer capacitance (C_dl), was larger in the doped samples. The C_dl value of the Fe-doped NiCo LDH was 3.72 mF/cm², significantly surpassing the 0.82 mF/cm² of the undoped NiCo LDH. These changes improved charge transfer and optimized reaction kinetics, enhancing the overall OER performance. This study offers significant contributions to the development of efficient electrocatalysts for the OER, advancing the understanding of key design principles for enhanced catalytic performance. Full article

Chiral molecules are ubiquitous in nature and biological systems, where the unique optical and physical properties of chiral nanoparticles are closely linked to their shapes. Synthesizing chiral plasmonic nanomaterials with precise structures and tunable sizes is essential for exploring their applications. This study presents a method for growing three-dimensional chiral gold nanoflowers (Au NFs) derived from trisoctahedral (TOH) nanocrystals using D-cysteine and L-cysteine as chiral inducers. By employing a two-step seed-mediated growth approach, stable chiral Au nanoparticles with customizable sizes, shapes, and optical properties were produced by adjusting the Au nanosphere (Au NP) seed concentration and cysteine dosage. These nanoparticles exhibited optical activity in both the visible and near-infrared regions, with a maximum anisotropy factor (g-factor) of 0.024. Furthermore, the PEG-modified chiral Au NFs demonstrated excellent biocompatibility. This approach provides a precise method for geometrically controlling the design of three-dimensional chiral nanomaterials, holding great potential for biomedical applications. Full article