Search Results (472)

In this study, a simple and effective approach was developed for the quantitative detection of serotonin. Hexagonal copper selenide nanostructures (CuSe) were employed to modify a disposable screen-printed carbon electrode (SPCE), and their ability to electrochemically detect serotonin in serum samples was investigated. The fabricated CuSe nanostructures exhibited an interconnected, cluster-like morphology composed of irregularly shaped particles with a distinct hexagonal crystal structure. The electrochemical results revealed that the CuSe/SPCE sensor showed better electrochemical activity and good analytical sensing performance towards serotonin detection. The sensor exhibited a linear response in the concentration range of 10 to 1000 nM, with an excellent correlation coefficient (R² = 0.9998) and a low detection limit of 3 nM. Furthermore, the CuSe/SPCE showed better selectivity, impressive sensitivity (12.45 µM/µA cm⁻²), and good reproducibility toward serotonin detection, making it a promising electrochemical biosensor for serotonin detection in various real biological samples. Full article

Electro-oxidation of ammonia has emerged as a promising route for sustainable energy conversion and pollutant mitigation. In this study, we report the facile fabrication of dendritic Cu@Pt core–shell nanostructures electrodeposited on pencil graphite, forming an efficient electrocatalyst for the ammonia oxidation reaction (AOR). The designed electrocatalyst exhibited high catalytic activity towards AOR, achieving high current density at very low potentials (−0.3 V vs. Ag/AgCl), with a lower Tafel slope of 16.4 mV/dec. The catalyst also demonstrated high electrochemical stability over 1000 potential cycles with a regeneration efficiency of 78%. In addition to catalysis, Cu@Pt/PGE facilitated very sensitive and selective electrochemical detection of ammonia nitrogen by differential pulse voltammetry, providing an extensive linear range (1 μM to 1 mM) and a low detection limit of 0.78 μM. The dual functionality of Cu@Pt highlights its potential in enhancing ammonia-based fuel cells and monitoring ammonia pollution in aquatic environments, thereby contributing to the development of sustainable energy and environmental technologies. Full article

The rapid growth in population and industrialization have significantly increased global energy demand, placing immense pressure on finite and environmentally harmful conventional fossil fuel-based energy sources. In this context, the development of hybrid electrocatalysts presents a crucial solution for energy conversion and storage, addressing environmental challenges while meeting rising energy needs. In this study, the fabrication of a novel bifunctional catalyst, copper nickel aluminum spinel (Cu_0.5Ni_0.5Al₂O₄) supported on graphitic carbon nitride (GCN), using a solid-state synthesis process is reported. Because of its effective interface design and spinel cubic structure, the Cu_0.5Ni_0.5Al₂O₄/GCN nanocomposite, as synthesized, performs exceptionally well in electrochemical energy conversion, such as the oxygen evolution reaction (OER), the hydrogen evolution reaction (HER), and energy storage. In particular, compared to noble metals, Pt/C- and IrO₂-based water-splitting cells require higher voltages (1.70 V), while for the Cu_0.5Ni_0.5Al₂O₄/GCN nanocomposite, a voltage of 1.49 V is sufficient to generate a current density of 10 mA cm⁻² in an alkaline solution. When used as supercapacitor electrode materials, Cu_0.5Ni_0.5Al₂O₄/GCN nanocomposites show a specific capacitance of 1290 F g⁻¹ at a current density of 1 A g⁻¹ and maintain a specific capacitance of 609 F g⁻¹ even at a higher current density of 5 A g⁻¹, suggesting exceptional rate performance and charge storage capacity. The electrode’s exceptional capacitive properties were further confirmed through the determination of the roughness factor (Rf), which represents surface heterogeneity and active area enhancement, with a value of 345.5. These distinctive characteristics render the Cu_0.5Ni_0.5Al₂O₄/GCN composite a compelling alternative to fossil fuels in the ongoing quest for a viable replacement. Undoubtedly, the creation of the Cu_0.5Ni_0.5Al₂O₄/GCN composite represents a significant breakthrough in addressing the energy crisis and environmental concerns. Owing to its unique composition and electrocatalytic characteristics, it is considered a feasible choice in the pursuit of ecologically sustainable alternatives to fossil fuels. Full article

In this study, we investigate the optical and structural properties of Cu-doped β-Ga₂O₃ nanostructures synthesized via a hydrothermal method, followed by annealing in ambient O₂. Different Cu doping concentrations (0, 1.6, and 4.8 at.%) are introduced to examine their effects on the crystal structure, chemical state, and optical bandgap of β-Ga₂O₃. X-ray diffraction (XRD) analysis reveals that the host β-Ga₂O₃ crystal structure is preserved at lower doping levels, whereas secondary phases (Ga₂CuO₄) appear at higher doping concentrations (4.8 at.%). X-ray photoelectron spectroscopy (XPS) confirms the presence of Cu²⁺ ions in both lattice substitution sites and surface-adsorbed hydroxylated species (Cu(OH)₂). The optical bandgap of β-Ga₂O₃ is found to decrease with increasing Cu concentration, likely due to the formation of localized states or secondary phases. These findings demonstrate the tunability of the optical properties of β-Ga₂O₃ via Cu doping, providing insights into the incorporation mechanisms and their impact on structural and electronic properties. Full article

The article suggests a simple one-step sol–gel method for synthesizing nanostructured zinc oxide films co-doped with copper and aluminum. It shows the possibility of forming hierarchical ZnO:Al:Cu nanostructures combining branches of different sizes and ranks and quasi-spherical fractal aggregates. It demonstrates the use of the synthesized samples as highly efficient photocatalysts providing the decomposition of toxic dyes (methyl orange) under the action of both ultraviolet radiation and visible light. It establishes the contribution of the average crystallite size, the proportion of zinc atoms in the crystalline phase, their nanostructure, as well as X-ray amorphous phases of copper and aluminum to the efficiency of the photocatalysis process. Full article

Polymer brushes (PBs) are transformative surface-modifying nanostructures, yet their synthesis via controlled methods like copper-mediated surface-initiated atom-transfer radical polymerization (Cu⁰-SI-ATRP) faces reproducibility challenges due to a lack of understanding of parameter interdependencies. This study systematically evaluates the Cu⁰-SI-ATRP process for polyacrylamide brushes (PAM-PBs), aiming to clarify key parameters that influence the synthesis process. This evaluation followed a step-by-step characterization that tracked molecular changes through infrared spectroscopy (IR) and surface development by contact angle (CA) through two different mixing methods: ultrasonic mixing and process simplification (Method A) and following literature-based parameters (Method B). Both methods, consisting of surface activation, 3-aminopropyltriethoxysilane (APTES) deposition, bromoisobutyryl bromide (BiBB) anchoring, and polymerization, were analyzed by varying parameters like concentration, temperature, and time. Results showed ultrasonication during surface activation enhanced siloxane (1139→1115 cm⁻¹) and amine (1531 cm⁻¹) group availability while reducing APTES concentration to 1 Vol% without drying sufficed for BiBB anchoring. BiBB exhibited insensitivity to concentration but benefited from premixing, evidenced by sharp C–Br (~1170 cm⁻¹) and methyl (3000–2800 cm⁻¹) bands. Additionally, it was observed that PAM-PBs improved with Method A, which had reduced variance in polymer fingerprint regions compared to Method B. Adding to the above, CA measurements gave complementary step-by-step information along the modifications of the surface, revealing distinct wettability behaviors between bulk PAM and synthesized PAM-PBs (from 51° to 37°). As such, this work identifies key parameter influence (e.g., mixing, BiBB concentration), simplifies steps (drying omission, lower APTES concentration), and demonstrates a step-by-step, systematic parameter decoupling that reduces variability. In essence, this detailed parameter analysis addresses the PAM-PBs synthesis process with better reproducibility than the previously reported synthesis method and achieves the identification of characteristic behaviors across the step-by-step process without the imperative need for higher-cost characterizations. Full article

Eskebornite (CuFeSe₂), a member of the I–III–VI₂ ternary semiconductor family, was explored in this study as a potential thermoelectric material, offering new insights into its synthesis, structural characteristics, and transport behavior. Structurally analogous to chalcopyrite (CuFeS₂)—an extensively studied antiferromagnetic semiconductor—eskebornite remains relatively underexplored, particularly regarding its solid-state synthesis and thermoelectric performance. To address this gap, pure eskebornite was synthesized via mechanical alloying followed by hot pressing, a method that enables the fine control of its phase composition and microstructural features. The synthesized undoped CuFeSe₂ exhibited p-type nondegenerate semiconducting behavior, with electrical conductivity increasing monotonically over the temperature range of 323–623 K, indicative of thermally activated carrier transport. Simultaneously, a decreasing trend in thermal conductivity with temperature was observed, likely resulting from intensified phonon scattering, which serves to suppress heat transport and enhance the thermoelectric efficiency by maintaining a thermal gradient across the material. A peak in the Seebeck coefficient occurred between 473 and 523 K, suggesting the onset of intrinsic carrier excitation and a transition in dominant carrier transport mechanisms. The material exhibited a maximum power factor of 1.55 μWm⁻¹K⁻², while the dimensionless thermoelectric figure of merit (ZT) reached a peak value of 0.37 × 10⁻³ at 523 K. Although the ZT remains low, these results underscore the potential of eskebornite as a thermoelectric candidate, with substantial room for optimization through chemical doping, microstructural engineering, or nanostructuring approaches to enhance the carrier mobility and reduce the lattice thermal conductivity. Full article

Cu-doped In₂O₃ nanocomposites with copper compositions of 1–3 wt.% are synthesized by a hydrothermal method using water or alcohol as a solvent. Cubic In₂O₃ is formed when water is used for synthesis, while composites synthesized in alcohol contain rhombohedral In₂O₃. This trend is independent of the amount of copper introduced. The Cu ions are shown to be uniformly distributed in the In₂O₃ nanoparticles without significant destruction of the indium oxide structure. All the composites exhibit a porous structure that depends on the solvent used for the synthesis. The addition of copper to both crystalline forms of indium oxide increases the resistance of the films and reduces the operating temperature. The phase state of indium oxide also affects the conductivity of the composites. There is an increase in sensory response to H₂ and CO with the introduction of Cu into samples with cubic structure, but a reduction in response in samples with the rhombohedral phase of indium oxide. Full article

As a pioneering exploration of gallium nitride (GaN) as reinforcement in metal matrix composites, this study systematically investigated the mechanical–electrical property evolution in copper matrix composites through controlled GaN incorporation—a research gap scarcely addressed previously. GaN-Cu composites with tailored GaN contents were successfully synthesized by precisely controlled mechanical alloying and powder metallurgical processing and exhibited exceptional mechanical–electrical synergies. Advanced microstructural characterization via X-ray diffraction and electron microscopy revealed the homogeneous dispersion of GaN nanoparticles within the Cu matrix, forming coherent interfacial structures. The characterization results show that GaN-Cu composites could be successfully prepared by mechanical alloying and powder metallurgy methods, and it was confirmed that GaN nanoparticles could improve the mechanical properties of metal matrix composites as reinforcement; with an exponential increase in GaN content, the decrease in conductivity became very slow. With an increase in GaN content, the electrical conductivity decreased in an “L” shape, while the hardness first increased and then decreased, but the hardness could reach up to 128.66 HV, which is about 130% higher than that of the substrate. Full article

Copper-thiolate nanostructures, formed through the self-assembly of cysteine (Cys) and glutathione (GSH) with copper ions, offer a versatile platform for redox-active applications due to their structural stability and chemical functionality. In this study, Cu-Cys-GSH nanoparticles were synthesized and employed to develop a capacitive biosensor for the ultralow concentration detection of hydrogen peroxide (H₂O₂). The detection mechanism leverages a Fenton-like reaction, where H₂O₂ interacts with Cu-Cys-GSH nanoparticles to generate hydroxyl radicals (·OH) through redox cycling between Cu²⁺ and Cu⁺ ions. These redox processes induce changes in the sensor’s surface charge and dielectric properties, enabling highly sensitive capacitive sensing at gold interdigitated electrodes (IDEs). The influence of chirality on sensing performance was investigated by synthesizing nanoparticles with both L- and D-cysteine enantiomers. Comparative analysis revealed that the stereochemistry of cysteine impacts the catalytic activity and sensor response, with Cu-L-Cys-GSH nanoparticles exhibiting superior performance. Specifically, the biosensor achieved a linear detection range from 1.0 fM to 1.0 pM and demonstrated an ultra-sensitive detection limit of 21.8 aM, outperforming many existing methods for H₂O₂ detection. The sensor’s practical performance was further validated using milk and saliva samples, yielding high recovery rates and confirming its robustness and accuracy for real-world applications. This study offers a disposable, low-cost sensing platform compatible with sustainable healthcare practices and facilitates easy integration into point-of-care diagnostic systems. Full article

This study compares the effects of adding Mo, Cu, and Sn elements on the decolorization performance of Fe₇₇Si₁₃B₉M₁ (M = Mo, Cu, or Sn) amorphous alloys. After the addition of Cu and Sn elements, the Fe-Si-B amorphous alloys generate three-dimensional (3D) petal-like nanostructured corrosion products during the decolorization process. These petal-like nanostructures possess a high specific surface area and excellent adsorption capacity, thereby effectively promoting the decolorization of dyes. Furthermore, the influence of Fe content variation on the decolorization performance of Fe_77+xSi_13−xB₉Cu₁ (x = 0, 2, or 4) and Fe_77+xSi_13−xB₉Sn₁ (x = 0, 2, or 4) alloys was investigated. The glass-forming ability of Fe_77+xSi_13−xB₉Cu₁ alloys decreases with increasing Fe content, leading to the precipitation of α-Fe crystalline phases starting from Fe₇₉Si₁₁B₉Cu₁. As the crystallinity increases, the decolorization performance of the alloys gradually deteriorates. In contrast, the Fe_77+xSi_13−xB₉Sn₁ alloys maintain their amorphous structure even with increasing Fe content, and their decolorization performance for Orange II improves accordingly. The high decolorization efficiency of FeSiBSn amorphous alloys for Orange II can be attributed to their unique self-refreshing properties. Full article

Nanotechnology is emerging as an innovative and sustainable agricultural approach that minimizes environmental impacts by developing nanostructured materials to promote plant growth and combat plant-parasitic nematodes (PPNs). Plant-based nanoparticles (NPs) are attracting increasing attention as they are more environmentally friendly, economical and biocompatible compared to traditional chemical and physical synthesis methods. The ability of plants to reduce and stabilize metal ions and form NPs of specific size and morphology through their biochemical content offers great advantages for agricultural applications. Phytochemicals produced by plants enable the biological synthesis of metal and metal oxide NPs by acting as reducing agents and coating agents in NP synthesis. The effects of plant-based NPs in nematode control are based on mechanisms such as the disruption of the nematode cuticle, induction of oxidative stress and interference with parasite metabolism. Several plant species have been investigated for the synthesis of metal and metal oxide nanoparticles such as silver (Ag-NPs), nickel oxide (NiO-NPs), zinc oxide (ZnO-NPs), copper oxide (CuO-NPs) and iron (Fe-NPs). These biologically synthesized NPs show potent biological activity against important PPNs such as Meloidogyne spp., Pratylenchus spp. and Heterodera spp. The integration of plant-derived NPs into agricultural systems has significant potential for plant growth promotion, nematode suppression and soil health improvement. This review highlights their role in reducing environmental impact in agricultural applications by examining the sustainable synthesis processes of plant-based NPs. Full article

Copper (Cu) nanoparticles, known for their high electrical conductivity and cost-effectiveness, have emerged as essential materials in various applications from flexible electronics to antimicrobial agents. This work focuses on the synthesis and characterization of semiconductive nanostructured films composed of polyvinyl alcohol (PVA) with embedded Cu nanoparticles. The study provides a comprehensive analysis of the structural, optical, electrical, and dielectric properties of the resulting nanocomposites. The results indicate a significant reduction in optical band gap, from 4.82 eV in pure PVA to 2.6–2.8 eV in the nanocomposites, alongside enhanced electrical conductivities reaching 1.20 S/cm for films with 5 wt.% Cu. Dielectric assessments further reveal high dielectric constants, underscoring the potential of these materials for flexible electronic applications. This work highlights the effectiveness of incorporating Cu nanoparticles into polymer matrices, paving the way for advanced materials that meet the demands of next-generation electronics. Full article

This study presents the preparation of hybrid iron oxide nanocomposites through a two-step process combining microfluidic-assisted synthesis and post-synthetic surface modification. Fe₃O₄ nanoparticles were synthesized and simultaneously functionalized with salicylic acid using a three-dimensional vortex-type microfluidic chip, enabling rapid and uniform particle formation. The resulting Fe₃O₄/SA nanostructures were further modified with either silver or copper oxide to form iron oxide nanocomposites with enhanced antimicrobial functionality. These nanocomposites were subsequently integrated into silica aerogel matrices using a dip-coating approach to improve surface dispersion, structural stability, and biocompatibility. The structural and morphological properties of the samples were investigated using XRD, FT-IR, TEM with SAED analysis, and Raman microscopy. In vitro cytotoxicity and antimicrobial assays demonstrated that Fe₃O₄/SA–Ag and Fe₃O₄/SA–CuO exhibit potent antibacterial activity and cell type-dependent biocompatibility. In vivo biodistribution studies showed no accumulation in major organs and selective clearance via the spleen, validating the systemic safety of the platform. These findings highlight the potential of the synthesized nanocomposites as biocompatible, antimicrobial coatings for advanced biomedical surfaces. Full article

Brasses are well-known structural materials, and their electrochemistry seems to be known. However, the formation of nanostructured anodic oxides on brasses is still not common and researched enough. Despite the electrochemical oxidation or anodization of copper and zinc being well-recognized and known in the scientific community, there is a lack of a satisfactory amount of research on brass anodizing. Both copper and zinc can passivate in neutral and alkaline electrolytes, and also the mechanism of the nanostructured oxide growth of both seems to be similar. In this review, much effort was put in to gather the information on the protocols on the electrochemical oxidations of brasses and their applications. Usually, the effects of electrochemical oxidation allow us to obtain nanostructured surfaces made of mixed Cu and Zn species. The formation of such composite nanostructures allows us to apply them in such emerging applications as photocatalytic organic pollutant decomposition, photoelectrochemical hydrogen generation, electrochemical carbon dioxide reduction reactions, or electrochemical methanol oxidation. Full article