Journal of Cluster Science最新文献

This work establishes a robust biomedical electrochemical platform for point-of-care sulfamerazine (SFZ) monitoring (requiring low volume and miniaturized potentiostat) by engineering a hierarchical ternary nanocomposite of polypyrrole, cobalt oxide, and manganese dioxide (PPy/Co₃O₄/MnO₂) on a glassy carbon electrode (GCE). The synergistic integration of the conductive PPy matrix with the electrocatalytic Co₃O₄ nanoparticles and high-surface-area MnO₂ nanorods was supported by through X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS) analyses. This unique architecture enhanced the electroactive surface area (0.172 cm²) and accelerated electron transfer kinetics, as evidenced by a low charge transfer resistance of 6.1 kΩ. The sensor facilitated an adsorption-controlled, irreversible oxidation of SFZ via a 2-electron, 2-proton transfer mechanism, confirmed by scan rate and pH studies. Under optimized Square Wave Voltammetry (SWV) conditions, the sensor exhibited a wide linear range (1-100 µM), a sensitivity of 0.502 µA/µM, and low detection and quantification limits of 0.45 ± 0.03 µM and 0.98 ± 0.05 µM, respectively. The platform demonstrated exceptional selectivity against common interferents and structurally similar drugs, alongside outstanding stability (95.2% signal retention) and reproducibility (RSD < 4.1%). Successful application in tap water, river water, and artificial urine yielded excellent recovery rates (97.1–103.4%), validating its potential for reliable SFZ detection in clinical and environmental monitoring.

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A green, sustainable, low temperature hydrothermal method is reported for the facile, cost-effective, eco-friendly synthesis of ultrathin BiOCl nanosheets with exposed {110} facets and enriched oxygen vacancies for the first time, using seawater as a precipitant and universal solvent and aloe-vera gel as a structure-directing agent. No harsh chemicals and special synthetic conditions were employed in the present method and the prepared sample was completely characterized. The XRD analysis confirmed the formation of tetragonal crystalline structure with highly exposed {110} facets. The two-dimensional nanosheet like surface morphology with an ultrathin lamellar structure was confirmed by the electron microscopic studies. The existence of high-density oxygen vacancies was validated by ESR characterization. The optical analysis indicated the visible light absorption of the BiOCl with a reduced band gap of 2.71 eV. The catalytic activity of the ultrathin BiOCl nanosheets was investigated for the visible-light driven photocatalytic degradation of methylene blue and tetracycline pollutant in aqueous medium and the sample attained a highest degradation efficiency of 99.8% and 85% with a maximum TOC mineralization efficiency of 37.8% and 24.5% for methylene blue and tetracycline respectively. The enhanced catalytic activity could be attributed to the nano crystallite size, highly exposed {001} facets, ultrathin nanosheet like morphology with a lamellar structure, high-density oxygen vacancies, high specific-surface area, mesoporosity, enhanced visible light absorption with reduced band gap and high charge carrier separation efficiency with increased life time of charge carriers. The sample was effectively reused five times without losing activity in the successive runs.

This study reports (Pd or Ag)/rGO nano-diodes in Schottky configuration and investigate its influence on the recovery characteristics. Temperature-dependent sensing tests for H₂, CO, and CH₄ (1 to 500 ppm) showed distinct thermal fingerprint profiles for each analyte, which help to draw out the selectivity conclusions. The relatively better sensing characteristics of these gas sensing devices are due to the multi-Schottky barrier of nano diodes at the metal/semiconductor interface. These diodes operate in parallel electrical configuration. Current-voltage (I-V) characteristics of devices were examined to calculate the multi-barrier Schottky barrier height. A non-linear behavior observed with conventional Richardson plot, arising from the interfacial inhomogeneity and resulting in multiple Schottky barrier at the metal-rGO interface. This was effectively addressed by incorporating Gaussian distribution in the framework and the extracted SBH shows the close agreement with sensing results. The barrier variation was modeled to understand the solid-gas interaction. More importantly, the devices showed excellent humidity tolerance, long-term stability and repeatability, by sustaining consistent sensing performance even after a 180 days.

The present study investigates the efficacy of CuAl materials derived from layered double hydroxides (LDH) in the advanced removal of organic matter and micropollutants (µP) in treated municipal wastewater from the M’sila region wastewater treatment plant, Algeria. The CuAl-CO₃ LDH material was synthesized by coprecipitation, then transformed by calcination at 500°C and 950°C to obtain the mixed CuO/γ-Al₂O₃ (CuAl-500) and spinel CuO/CuAl₂O₄ (CuAl-950) oxides, respectively. The materials were characterized by their textural, electrochemical, and surface properties, revealing marked differences in specific surface area, band gap, and pH_PZC. The catalytic performance of photocatalysis (UV), ozonation (O₃), and photo-ozonation (UV + O₃) processes was evaluated in terms of chemical oxygen demand reduction and degradation of µP identified by GC-MS. The results highlight distinct catalytic behaviors depending on the treatment process. Under ozonation conditions, CuAl-CO₃ exhibited the highest catalytic efficiency due to its hydroxyl-rich surface and strong O₃ activation ability. In contrast, CuAl-500 showed superior performance under UV and UV/O₃ processes, owing to its optimized electronic conductivity, enhanced charge separation, and improved generation of reactive oxygen species (left(HO^bullet/ O_2^{bullet-}right)). The combined UV + O₃/CuAl-500 system achieved the highest mineralization and µP removal efficiency, together with improved energy efficiency.

The widespread contamination of water by industrial dyes and the increasing threat of drug-resistant pathogens present urgent environmental and biomedical challenges. Current remediation and antimicrobial strategies often suffer from inefficiency, high cost, and environmental toxicity. To address this, we developed a sustainable, dual-purpose Fluorescent Carbon Nanoparticles (FCNs) via a one-pot hydrothermal synthesis using Arthrospira (Spirulina) biomass. FCNs synthesis was confirmed with spectroscopic and microscopic techniques i.e. Ultraviolet-Visible (UV-Vis) spectroscopy, Photoluminescence (PL) spectroscopy, Fourier-Transform Infrared (FTIR) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), and zeta potential. UV, PL and FTIR indicate the presence of characteristic absorption peaks at 238 and 434 nm, excitation-dependent blue photoluminescence, and presence of characteristic functional groups (OH, C = O, C─O). The images of FESEM demonstrated a quasi-spherical morphology whereas zeta potential was − 13.10 mV, which highlights moderate stability. XRD identified a carbon-related reflection at 28.27° at the (100) plane and Scherrer analysis indicated a crystallite size of 26 ± 3.90 nm. The FCNs indicated remarkable photocatalytic efficiency, with 67.80% degradation of crystal violet in 120 min under visible light. Antioxidant activity was dose-dependent with significant scavenging activity of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) (IC₅₀ = 74.90 µg/mL), Hydrogen peroxide (H₂O₂) (IC₅₀ = 132.10 µg/mL) and total antioxidant capacity (TAC) (IC₅₀ = 123 µg/mL). Moreover, enzyme inhibition assays indicated significant alpha-amylase inhibitory activity (IC₅₀= 136 µg/mL). The FCNs also exhibited broad-spectrum antibacterial activity against bacterial strains and antifungal potential against Alternaria alternata (IC₅₀= 155.40 µg/mL). They demonstrated good hemocompatibility (under 5% hemolysis at 90 µg/mL) and moderate cytotoxicity in brine shrimp assays (LC₅₀= 126 µg/mL). Further, there was mild dose-dependent protein kinase inhibition. Overall, this paper highlights Arthrospira-derived FCNs as an attractive green nanoplatform for combined environmental remediation and biomedical applications.

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Graphical abstract illustrating synthesis of Arthrospira-mediated FCNs, Characterization and biological applications

In this study, Candida rugosa lipase (CRL) was embedded within nano-zeolitic imidazolate framework-8, nZIF-8 (1:35), synthesized with a zinc(II) ion to 2-methylimidazole (Zn²⁺: HmeIM) ratio of 1:35 using a water-based, de novo synthesis method at ambient temperature without any modulating agents. The optimization of the embedding process focused on three parameters: the molar ratio of zinc(II) ion to 2-methylimidazole (Zn²⁺: HmeIM), the concentration of partially purified lipase, and the duration of embedding process. Various physicochemical characterization techniques were employed to confirm and analyze the embedded lipase, including powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. Additional characterization methods such as thermogravimetric analysis (TGA), N₂ adsorption-desorption measurements, and Fourier transform infrared spectroscopy (FTIR) were also conducted for comprehensive analysis. The amount of lipase successfully embedded was quantified using the standard Bradford assay, with CRL₃@nZIF-8(1:35) (Candida rugosa lipase (3.0 mg) immobilized on nano ZIF-8 synthesized with a Zn²⁺:HmeIM ratio of 1:35) achieving the highest immobilization of 89% with loading capacity of 17.7 mg/g. To evaluate the functional performance of the immobilized enzyme, a p-nitrophenyl palmitate (p-NPPal) hydrolysis assay was performed. The results showed a six-fold increase in enzymatic activity compared to the soluble lipase. These findings highlight the potential of nZIF-8(1:35) as a promising support material for lipase immobilization, functioning as a robust protective nanocomposite and as an enhancer of enzymatic performance, with the added capability of reusability in the CRL₃@nZIF-8(1:35) system.

This study introduces a sustainable magnetic nanobiosorbent derived from Fe₃O₄ nanoparticles immobilized onto Cladosporium herbarum (Fe₃O₄@CH) for the effective removal and quantification of Zn(II) in aqueous and food matrices. The synthesized composite was characterized using various techniques, confirming successful immobilization and demonstrating a significant adsorption capacity of 760.1 mg/g, approximately 7.3 times that of the raw biomass (103.1 mg/g). The adsorption process was highly pH-dependent, with optimal removal observed at pH 8.0. Equilibrium data conformed to the Langmuir isotherm model (R² = 0.977), and kinetic analysis followed pseudo-second-order kinetics (R² = 0.997), suggesting chemisorption involving Zn–O and Zn–N coordination, as corroborated by XPS analysis. The analytical method exhibited excellent performance, with LOD of 0.079 µg/L, LOQ of 0.264 µg/L, and RSD of 2.38%. The nanobiosorbent retained over 95% removal efficiency after 10 adsorption–desorption cycles and demonstrated high tolerance to various interfering ions at up to 250 mg/L. Application to microwave-assisted digested bulgur samples yielded recovery rates of 95%-105%, confirming analytical accuracy and minimal matrix effects. These findings highlight that Fe₃O₄@CH is an efficient, reusable, and cost-effective magnetic biosorbent with considerable potential for trace Zn(II) removal and quantification in complex matrices.

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The superatom concept has evolved from describing metal clusters with atom-like electronic shells to a broader framework for understanding quantized electronic states in confined systems. While traditional superatoms rely on structurally enclosed confinement within metallic clusters, this review highlights a distinct regime: coordination‑mediated (non‑enclosed) confinement in metal complexes, where a fully saturated and symmetric ligand sphere generates an effective potential that induces quantized electronic shells without physical enclosure. Three paradigm‑shifting advances are outlined: (1) superatomic character is defined not by geometry but by radial quantization overriding chemical directionality; (2) ligand saturation serves as a chemical tool for potential averaging, enabling shell formation through chemical rather than structural confinement; and (3) f-element complexes such as [Ac(H₂O)₉]³⁺ provide a critical test case, where the superatom model offers the most parsimonious explanation where classical ligand-field approaches fall short. This review detail the electronic shells and emergent magic numbers in such systems, supported by spectroscopic and computational evidence, and explicitly distinguish magic‑number‑like shell closure (sequential shells with gaps) from classical electron‑counting rules (e.g., 18‑electron rule). Finally, it establishes a unified theoretical framework bridging clusters, coordination compounds, and heavy‑element chemistry under a common quantum‑mechanical principle, offering a roadmap for the rational design of superatomic coordination compounds.

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Roughly spherical-shaped MnO₂ nanoparticles (NPs; 1–5.5 nm), Ag/AgO/Ag₂O NPs (4–18 nm), and Ag/Mn₃O₄ nanocomposites (6–24 nm) were biosynthesised and evaluated for their antimicrobial activity against critical and high-priority bacterial pathogens listed in the Indian Priority-Pathogen List, along with common antibiotic-resistant waterborne bacteria. Antimicrobial efficacy was assessed using disc-diffusion and growth-curve assays against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, Vibrio cholerae, Streptococcus pyogenes, and Proteus mirabilis. MnO₂ NPs did not exhibit antimicrobial activity against any of the eight tested strains. In contrast, Ag/AgO/Ag₂O NPs inhibited six of the eight strains, showing a maximum zone of inhibition (ZOI) of 5.3 ± 0.6 mm against S. aureus. The Ag/Mn₃O₄ nanocomposite demonstrated superior antimicrobial performance, inhibiting all eight bacterial strains with greater efficacy than Ag/AgO/Ag₂O NPs, and produced a maximum ZOI of 6.7 ± 0.6 mm against P. aeruginosa. For B. cereus, both nanomaterials exhibited minimum inhibitory concentrations of 2 ng/µL and IC₅₀ values of 0.7 ng/µL; however, the minimum bactericidal concentration for Ag/AgO/Ag₂O NPs was 4 ng/µL. Haemocompatibility analysis revealed that the non-haemolytic concentrations for Ag/AgO/Ag₂O, MnO₂, and Ag/Mn₃O₄ nanomaterials were 0.01, 1.0, and 0.1 µg/µL, respectively, while the haemolytic concentrations (HC₁₀) values for Ag/AgO/Ag₂O and Ag/Mn₃O₄ were 0.3 and 0.6 µg/µL, respectively.

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The removal of organic dyes from wastewater poses a significant environmental challenge due to their high durability and toxicity. This study investigated magnetic Fe₃O₄-based nanocomposites, e.g., Fe₃O₄, Fe₃O₄@CFs, Fe₃O₄@CNTs, and Fe₃O₄@G, for their efficacy in adsorbing and catalytically hydrogenating Eriochrome Black T (ET) and Phenol Red (PR) in aqueous solution. The superparamagnetic properties of the material enable the separation of materials from solutions using an external magnetic field. The materials can be removed from the solution using an external magnet. The adsorption performance demonstrated capacities of 20–70 mg/g for ET and 15–65 mg/g for PR, indicating the enhanced adsorption efficacy of carbon-supported magnetic nanocomposites. The characterization of the materials post-adsorption, utilizing FT-IR and diffuse reflectance spectroscopy, verified the presence of dye molecules on the adsorbent surfaces without any structural alterations to the materials. The catalytic hydrogenation of the dyes was assessed using sodium borohydride (NaBH₄) as a reducing agent. The removal efficiencies via catalytic hydrogenation were 100% for ET and PR. The magnetic nanocomposites demonstrated exceptional recyclability over 4 cycles, with negligible decline in catalytic efficiency, and their magnetic characteristics facilitated straightforward recovery using an external magnet. The results indicate that Fe₃O₄–carbon nanocomposites are effective, reusable catalysts and adsorbents for the efficient removal of dyes in wastewater treatment applications.