Journal of Cluster Science最新文献

This study presents the novel development of heterostructure Fe₂O₃/BiVO₄ composites as efficient photocatalysts, specifically utilizing a 20-W UV-A lamp for low-energy, sustainable environmental remediation. The combination of Fe₂O₃ and BiVO₄ produces a composite with enhanced photocatalytic performance through synergistic interactions. The composites were synthesized through a hydrothermal process with varied Fe ratios, followed by calcination. Characterization techniques, including XRD, SEM, TEM, EDS, XPS, BET surface area analysis, UV-DRS, and PL, confirmed composite formation, optimal particle dispersion, and improved surface properties. UV-DRS showed visible light absorption (bandgap energies: 2.27–2.47 eV), and PL confirmed effective charge separation critical for photocatalysis. Under low-power UV-A irradiation, the composite achieved 98.74% degradation of methylene blue (MB) with a rate constant of 0.0270 min⁻¹, outperforming the individual Fe₂O₃ and BiVO₄ components. This work demonstrates the potential of heterostructure Fe₂O₃/BiVO₄ composites as eco-friendly, high-efficiency photocatalysts, offering a sustainable approach to environmental cleanup and advancing the application of low-energy photocatalytic systems in broader photocatalysis fields.

Polyoxometalates (POMs), a class of discrete metal-oxo clusters with diverse structures and properties, are used in energy, biology, catalysis, and sensing applications, as well as in material design and assembly. POM-based catalysts, which have adjustable compositions and abundant available structures, have useful characteristics, such as having a tunable acid-base, being redox stable, being recyclable, and having sustainable features. Nerve agents are a type of chemical warfare agent (CWA) which are easily available and pose threats to human security and the environment. POM-based catalysts can be used in the catalytic decontamination of nerve agents. This review provides a basic introduction to the catalytic decontamination of nerve agents by POM-based catalysts that are classified according to the methods used for the catalytic degradation of the nerve agents. This review summarizes the breakthroughs in the development of POM-based catalysts for the degradation of CWAs over the past decade and discusses the benefits, challenges, and opportunities in the use of POM-based catalysts for the catalytic decontamination of nerve agents.

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This review summarizes research progresses of polyoxometalate-based catalysts on catalytic decontamination of nerve agents in the past decade with an emphasis on the design, structures and their catalyst performances

All-inorganic perovskite quantum dots have sparked a research boom due to their excellent optical properties, however, their own strong ionicity and lead toxicity have hindered further development in the field of sensing. In this study, we have solved the toxicity problem of lead-based perovskite quantum dots by replacing lead with green metal bismuth. Meanwhile, due to the ligand-passivation effect of oleylamine and oleic acid, we successfully synthesized highly stable bismuth-based perovskite quantum dots(Cs₃Bi₂Br₉ PQDs)in ethanol, and constructed the environment-friendly fluorescence sensor for the quantitative detection of oxytetracycline (OTC) for the first time. The results demonstrated that the fluorescence quenching degree of Cs₃Bi₂Br₉ PQDs showed a good linear relationship with the concentration of OTC within the range of 2.0 ~ 18 µM, and the detection limit was 0.432 µM. By studying fluorescence lifetime, absorption spectroscopy, and evaluation of internal filtration parameters, it was proved that the sensing mechanism was caused by the inner filter effect owing to the overlapping of fluorescence emission spectrum of Cs₃Bi₂Br₉ PQDs and UV absorption spectrum of OTC. Moreover, Cs₃Bi₂Br₉ PQDs fluorescent sensor had good selectivity and anti-interference ability. It is believed that this work will open up a new way for lead-free perovskite quantum dots fluorescence sensor in the field of analytical detection.

Ni_0.6−xZn_xMn_0.4Fe₂O₄ (x = 0.0,0.2,0.4,0.6) were prepared by the combustion method using hexamine as the fuel. Zinc replacement in place of Ni and its effect on various structural, electric, magnetic, and dielectric properties was studied using several instrumental techniques. X-ray diffraction revealed a monophasic cubic spinel structure for the samples. Scherrer’s formula determined that the crystallite size (D) was in the nano range from 8 to 15 nm. The lattice constant values showed an increment with zinc content while porosity was seen to drop. The scanning electron microscopy images showcased agglomerated particles due to magnetic interaction between them and were found to have spherical morphology. TEM provided the average particle size obtained from the histogram, while the SAED pattern revealed the semicrystalline nature of the samples. Infrared spectra showed two metal-oxygen peaks peculiar to spinel ferrite in the range of ~ 400–600 cm^− 1. Confirmation of the spinel phase was made using room temperature Raman analysis, and the change in Raman peaks was observed with an increase in zinc content. XPS studies revealed Ni^+ 2, Mn^+ 2, Zn^+ 2, and Fe^+ 3 to be in their respective valence states. A resistivity study was conducted from RT- 500 °C, which showed a decrease in resistivity with an increase in temperature, a typical trend of semiconduction. Dielectric studies performed at RT showed the highest dielectric constant with the minimum dielectric loss for sample x = 0.2, while variable temperatures studied at different frequencies showed x = 0.6 with the highest dielectric constant. Saturation magnetization values increased up to x = 0.4, which Neel’s two sublattices model explained, and a further decrease in magnetization was explained by the Yafet- Kittle model. AC susceptibility revealed Curie temperature up to the point where the sample behaved as ferrimagnetic material. The main aim and objective were to explore the suitability of synthesized materials for their applications and to study zinc’s influence on various properties and antibacterial activity. The antibacterial activity of the samples was investigated as a potential candidate against highly resistant and infectious Staphylococcus aureus, and sample x = 0.2 showed the best results.

With the growing concern over the environmental and health risks posed by antibiotic contamination in water systems, this study evaluates the potential of iron and cobalt oxide nanocatalysts with varying molar ratios, synthesized using the co-precipitation method, for the efficient removal of antibiotics from aqueous solutions. The optimal nanocatalysts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), revealing high surface area and well-defined crystalline structures, enhancing catalytic activity. Kinetic analysis showed that Co_0.5Fe_0.5Fe₂O₄ exhibited the best performance, with a Michaelis–Menten constant (K_m) of 0.0366 mM and maximum reaction velocity (V_max) of 1.10 × 10⁻⁴ µM.min⁻¹. The reaction rate constants, k₁ = 6.12 × 10³ M⁻¹ S⁻¹ and k₃ = 3.64 × 10² M⁻¹ S⁻¹) and turnover number (kcat = 5.213 × 10⁻¹ S⁻¹) confirmed its superior catalytic properties. Antibiotic removal was further evaluated through batch adsorption experiments, with adsorption kinetics and isotherms studied to determine optimal conditions for antibiotic removal. The Co_0.5Fe_0.5Fe₂O₄ nanocatalyst exhibited superior peroxidase-like activity compared to the other nanocatalysts when tested with the common chromogenic substrate 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) diammonium salt. Based on this enzymatic activity, a colorimetric sensing platform was designed for H₂O₂ detection. Additionally, the Co_0.5Fe_0.5Fe₂O₄ nanocatalyst exhibited excellent adsorption capacity for various antibiotics, including ciprofloxacin, azithromycin, levofloxacin, moxifloxacin, amoxicillin, and metronidazole, with 100% removal efficiency under optimal conditions. This study highlights the potential of enzyme-mimicking nanostructures as efficient adsorbents for the removal of antibiotics from aqueous solutions, addressing significant environmental challenges posed by antibiotic contamination.

Globally, the major threat is the rise of antimicrobial-resistant diseases and the increasing incidence of cancer, both of which are leading causes of death due to a lack of effective therapies. Nanocomposites (NCs) have recently emerged as an alternative therapeutic agent for the development of novel medications. The current study demonstrates the fast production of Ag-HAp NCs with an aqueous bark extract of Acacia nilotica and evaluates their antiquorum sensing and anticancer activities. UV-vis spectroscopy, Fourier-transformed infrared spectroscopy, X-ray diffraction analysis, zeta sizer, field emission scanning electron microscopy, and high-resolution transmission electron microscopy were used to evaluate the physicochemical and morphological observations of Ag-HAp NCs. The biofabricated NCs demonstrated the ability to inhibit the violacein production in bioreporter strain Chromobacterium violaceum and mitigate the virulent factors in multidrug-resistant Proteus mirabilis. Sub-MIC concentrations of 2% Ag-HAp NCs (80 µg/mL) efficiently decreased the quorum sensing regulated virulence factors such as biofilm formation, exopolysaccharide synthesis, urease, hemolysin, and cell motility, that contribute to antibiotic resistance. Furthermore, an invitro cytotoxicity study of 2% Ag-HAp NCs revealed exceptional anticancer potential against the MCF-7 cell line using MTT assay. The microscopic studies (ROS and DAPI assay) demonstrated that the synthesized NCs elicit cellular cytotoxicity at a low dosage (IC₅₀ − 23.2 µg/mL). All experiments were carried out in triplicate (n = 3) to establish the statistical significance. Thus, phyto-mediated synthesized 2% Ag-HAp NCs are environmentally acceptable and non-toxic nanomaterials suitable for biomedical applications.

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The timely repair of injured skin is of outmost importance as the impaired wound healing may provoke infections, formation of scarring tissues, and delayed wound closure. ThQ + Rut-loaded NC gel was produced using the ultrasonication nanoprecipitation technique and investigated for dermal wound healing. Formulations were characterized for particle size distribution, and ζ − potential, % drug entrapment, and % loading. The optimum NC gel was characterized for viscosity, spreadability, and gel texture. The optimized nanocrystal gel was produced and tested on fibroblast cell line and tested in vivo for healing assessment. The optimum particle size of obtained NC was 192 ± 2 nm, PDI of 0.201, with a ζ-potential of -9.9 ± 1.9 mV. Further, Rut and ThQ entrapment and loading from ThQ + Rut-loaded NC gel, were measured to 89 ± 0.9%, 85.7 ± 1.5%; 21 ± 2%, and 17.5 ± 2%. The NC gel showed viscosity of 1488 ± 0.12 mPa*s at shear rate of 40 (1/s). The hydrogel texture analysis revealed firmness, consistency and cohesiveness of 43.88 g, 208.19 g.sec, and − 15.88 g, respectively. The cell viability studies revealed that Rutin and ThQ in NC gel significantly enhanced proliferation of fibroblast cell vis-a-vis to drug suspensions (p < 0.01). The histopathology demonstrated that ThQ + Rut-loaded NC gel improved collagen formation and tissue remodelling towards wound healing compared with other treatment groups. Thus, we may conclude that Rut and ThQ from nanocrystal gel is safe and will improve the dermal wound healing process.

Cellulose nanocrystals (CNC) are a sustainable, biodegradable, and versatile material with numerous advantageous and potential applications in diverse industries. For the first time, CNC was derived from the biomass of Dictyota bartayresiana, a brown seaweed from Dictyotaceae, having commercial value and therapeutic benefits. This process involved comprehensive extraction techniques, including acid hydrolysis and mechanical dispersion, to transform the seaweed into nanocellulosic material. The structural analysis, conducted via Transmission Electron Microscopy (TEM), affirmed that the resulting CNC displayed an average width of approximately 26 nm and a length extending to 520 nm long. X-ray Diffraction (XRD) analysis indicated that these extracted CNC constituted around 62% of the crystallinity index. Fourier Transform Infrared (FTIR) spectral analysis confirmed the successive removal of non-cellulosic components through chemical treatments. Elemental analysis (CHNS) validated the presence of sulfate groups, accounting for 0.59%. Thermogravimetric Analysis (TGA) results unveiled the superior thermal stability of the extracted CNC.

Ceria-supported copper catalysts exhibit high catalytic performance in the preferential oxidation of CO in excess H₂ (CO PROX). Highly dispersed copper oxide species have been experimentally identified as active centers. However, structural diagnostics of highly dispersed CuO_x species and CuO_x/CeO₂ interface areas remains a challenge. Here, we report a comprehensive structural study of a supported CuO/CeO₂ catalyst (5 wt% Cu) showing good activity in the CO PROX process. X-ray absorption spectroscopy (XAS) techniques and X-ray atomic pair distribution function (PDF) analysis were used as efficient methods for probing the atomic resolution structure. It was established that the catalyst contains Cu²⁺ species, mainly in the form of ultra-dispersed CuO-like particles and copper oxide clusters. Analysis of the local atomic arrangement revealed an interaction between copper ions and ceria surface. Oxygen-terminated {100} ceria facets can accommodate Cu²⁺ ions in square planar coordination. Moreover, some Cu ions are inserted into the CeO₂ crystal structure, forming a substitutional solid solution.

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The increasing antibiotic resistance necessitates sustainable methods for synthesizing antibacterial nanoparticles. This study focuses on the bio-assisted synthesis of silver/silver chloride nanoparticles (Ag/AgCl-NPs) using aqueous extracts of Acalypha arvensis, Hampea rovirosae, and Inga jinicuil. Polyphenols and flavonoids were quantified, and functional groups were analyzed via Fourier-transform infrared to assess their influence on the properties of Ag/AgCl-NPs. The effects of thermal treatment at 60 and 500 °C on the NPs’ size, morphology, and antibacterial efficacy were assessed. UV–Vis spectroscopy indicated absorption peaks between 430 and 449 nm, while X-ray diffraction analysis confirmed the presence of metallic Ag and a cubic AgCl structure, with crystallite sizes ranging from 11–51 and 28–60 nm, respectively. Dynamic light scattering showed hydrodynamic sizes of up to 127.2 ± 0.9 nm at 60 °C and up to 348.9 ± 10.7 nm at 500 °C. Field emission scanning electron microscopy micrographs exhibited a quasi-spherical morphology with significant agglomeration; showing particle sizes between 55 ± 11 and 81 ± 28 nm at 60 °C, and up to 135 ± 65 nm at 500 °C. X-ray photoelectron spectroscopy confirmed the metallic silver (Ag⁰), organic molecules, and absorbed chlorides on the NP surface. Pearson correlation analysis indicated a strong positive correlation between polyphenol content and NPs yield (r = 0.922), while it indicated a strong negative correlation with flavonoid content (r = −0.996). Additionally, a negative correlation was found between hydrodynamic size and antibacterial activity against Staphylococcus aureus (r = −0.854). The Ag/AgCl-NPs, after drying at 60 and 500 °C, were tested against Escherichia coli and S. aureus with minimum bactericidal concentrations below 19 µg/mL against E. coli. Minimum inhibitory concentration (MIC) for Ag/AgCl-NPs synthesized with A. arvensis and H. rovirosae extracts were above 312 µg/mL for S. aureus, while those synthesized with I. jinicuil showed MIC as low as 156 µg/mL. These results highlight the potential of medicinal plant extracts in the synthesis of Ag/AgCl with enhanced antibacterial properties.