Search Results (16)

The SnO₂-TiO₂ binary nanocomposites’ metal oxide was synthesized by a co-precipitation method and potentially utilized for wastewater treatment applications. The average crystallite size, dislocation density, and micro strain of the synthesized nanocomposites were calculated by the Debye–Scherrer, modified Debye–Scherrer, and W–H methods. The nanocomposites exhibit a tetragonal crystal structure with 62% crystallinity. The presence of Ti–O–Ti and Sn–O–Sn bonds was identified using the FTIR technique. The surface morphology was examined during SEM and EDAX analyses. The optical properties were interpreted with the help of UV–Vis and PL spectroscopy, and the bandgap energy was ascertained. From the CV and EIS studies, the behavior of the diffusive and capacitive natures was determined. Photocatalytic studies were carried out under sunlight and UV light by degrading (cationic) malachite dye at concentrations of 10, 20, and 40 mg/L. When analyzed with seven kinetic models, it was inferred that a pseudo-second and first-order were followed under visible and UV light. The maximum degradation efficiency of 94% was achieved for the 20 mg/L dye concentration within 50 min under UV and 150 min under solar irradiation. Complete decolorization was observed for both 10 mg/L and 20 mg/L dye concentrations under both irradiations. Full article

Pharmaceutical residues are increasingly emerging in global drinking water sources, posing serious ecological and public health challenges by altering the physicochemical balance of aquatic systems. Among available purification approaches, adsorption remains one of the most promising techniques due to its simplicity, cost-effectiveness, and efficiency. In this work, a ternary nanocomposite of Cu- and ZnO-decorated carboxylated graphene oxide (Cu/ZnO@CGO) was synthesized and utilized for highly efficient and ultrafast removal of the antidiabetic drug metformin from aqueous environments. The adsorption mechanism arises from a synergistic combination of surface complexation on Cu nanoparticles, cation–π and π–π electron donor–acceptor interactions with the CGO aromatic structure, and hydrogen bonding through the amino groups of metformin and the oxygen-rich functional moieties of ZnO and CGO. The nanocomposite was thoroughly characterized using FTIR, XPS, XRD, SEM, HRTEM, and TGA analyses, confirming its well-defined hybrid structure. Unlike conventional single-phase or binary systems, the Cu/ZnO@CGO nanocomposite demonstrated remarkable cooperative effects that enhanced its performance through the integration of metal–ligand coordination, π–π stacking, cation–π forces, and hydrogen bonding. These interactions contributed to an outstanding adsorption capacity of 232.56 mg·g⁻¹ and an exceptionally fast equilibrium time of only 25 min. Moreover, the material maintained excellent reusability, with merely a 4.1% decline in efficiency after five regeneration cycles, and achieved almost complete removal of metformin (99.7 ± 3.4%) from several real water samples, namely river, tap, and bottled water. The unique structural design of Cu/ZnO@CGO prevents CGO aggregation and facilitates efficient contaminant capture even at trace concentrations, establishing it as a highly competitive and sustainable adsorbent for pharmaceutical wastewater treatment. Overall, this study highlights a novel and rationally engineered nanocomposite whose synergistic surface chemistry bridges adsorption and detoxification, providing valuable insight into the next generation of multifunctional graphene-based materials for environmental remediation. Full article

Binary metallic nickel–copper nanocatalysts were anchored onto a polyvinylidene fluoride-co-hexafluoropropylene membrane [NiCu/PVdF–HFP] using the electrospinning technique, followed by the chemical reduction of the relevant precursor salts by introducing sodium borohydride to the synthesis mixture. A series of varied Ni:Cu weight % proportions was developed in order to optimize the electroactivity of this binary nanocomposite towards the investigated oxidation process. A number of physicochemical tools were used to ascertain the morphology and chemical structure of the formed metallic species on polymeric films. Cyclic voltammetric studies revealed a satisfactory performance of altered NiCu/PVdF–HFP membranes in alkaline solution. Ethylene glycol molecules were successfully electro-oxidized at their surfaces, showing the highest current intensity [564.88 μA cm⁻²] at the one with Ni:Cu weight ratios of 5:5. The dependence of these metallic membranes’ behavior on the added alcohol concentration to the reaction electrolyte and the adjusted scan rate during the electrochemical measurement was carefully investigated. One hundred repeated scans did not significantly deteriorate the NiCu/PVdF–HFP nanostructures’ durability. Decay percentages of 76.90–87.95% were monitored at their surfaces, supporting the stabilized performance for prolonged periods. A much-decreased R_ct value was estimated at Ni₅Cu₅/PVdF–HFP [392.6 Ohm cm²] as a consequence of the feasibility of the electron transfer step for the electro-catalyzing oxidation process of alcohol molecules. These enhanced study results will hopefully motivate the interested workers to explore the behavior of many binary and ternary combinations of metallic nanomaterials after their deposition onto convenient polymeric films for vital electrochemical reactions. Full article

Efficiently treating wastewater, particularly the elimination of heavy metal ions from water systems, continues to be one of the most pressing and complex challenges in modern environmental management. In this work, reduced graphene oxide coupled silver molybdate binary nanocomposites (RGO-Ag₂MoO₄ NCs) have been prepared via hydrothermal method. The crystalline nature and surface properties of the developed RGO-Ag₂MoO₄ NCs were proved by XRD, FTIR, SEM, and EDS techniques. Adsorption experiments demonstrated that the nanocomposites (NCs) effectively removed Pb(II) ions within 120 min, achieving a maximum removal efficiency ranging from 94.96% to 86.37% for Pb(II) concentrations between 20 and 100 mg/L at pH 6. Kinetic studies showed that the adsorption process followed a pseudo-second order model. Isotherm analysis presented that the Langmuir model provided the greatest fit for the equilibrium data, with a monolayer adsorption capacity of 128.94 mg/g. Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic. The results of this study highlight RGO-Ag₂MoO₄ NCs as a highly promising and eco-friendly material for the effective elimination of Pb(II) ions from wastewater. Their strong adsorption capacity, coupled with sustainable properties, makes them an efficient solution for addressing lead contamination, offering significant potential for practical applications in water treatment systems. Full article

Generally, our ecosystem is continuously contaminated as a result of anthropogenic activities that form the basis of our comfort in our routine life. Thus, most scientists are engaged in the development of new technologies that can be used in environmental remediation. Herein, highly calcined binary metal oxide (Er₂O₃@NiO) semiconductor nanocomposite (NC) was synthesized using a classical wet chemical process with the intention to both detect and degrade the toxic chemicals in an aqueous medium using a novel electrochemical current–potential (I–V) approach for the first time. Optical, morphological, and structural properties of the newly synthesized semiconductor NC were also studied in detail using FT-IR, UV/Vis., FESEM-EDS, XPS, BET, EIS, and XRD techniques. Then, a modified glassy carbon electrode (GCE) based on the newly synthesized semiconductor nanocomposite (Er₂O₃@NiO-NC/Nafion/GCE) as a selective electrochemical sensor was fabricated with the help of 5% ethanolic-Nafion as the conducting polymer binder in order to both detect and electro-hydrolyze toxic chemicals in an aqueous medium. Comparative study showed that this newly developed Er₂O₃@NiO-NC/Nafion/GCE was found to be very selective against m-tolyl hydrazine (m-Tolyl HDZN) and to have good affinity in the presence of other interfering toxic chemicals. Analytical parameters were also studied in this approach to optimize the newly designed Er₂O₃@NiO-NC/Nafion/GCE as an efficient and selective m-Tolyl HDZN sensor. Its limit of detection (LOD) at an SNR of 3 was calculated as 0.066 pM over the linear dynamic range (LDR) of our target analyte concentration (0.1 pM–0.1 mM). The limit of quantification (LOQ) and sensitivity were also calculated as 0.22 pM and 14.50 µAµM⁻¹cm⁻², respectively. m-Tolyl HDZN is among the toxic chemicals in our ecosystem that have lethal effects in living beings. Therefore, this newly designed electrochemical sensor based on semiconductor nanostructure material offers, for the first time, a cost-effective technique, in addition to long-term stability, that can be used as an alternative for efficiently probing other toxic chemicals in real samples. Full article

In this paper, we report on novel polyimide (PI) nanocomposites filled with binary mixtures of metal oxide (either TiO₂ or ZrO₂) nanoparticles and nanocarbon (either carbon nanofibers (CNFs) or functionalized carbon nanotubes (CNT_fs)). The structure and morphology of the materials obtained were comprehensively studied. An exhaustive investigation of their thermal and mechanical properties was performed. We revealed a synergistic effect of the nanoconstituents with regard to a number of functional characteristics of the PIs compared with single-filler nanocomposites, including thermal stability, stiffness (below and above glass transition temperature), yield point, and temperature of flowing. Moreover, the possibility of manipulating the properties of the materials by choosing a proper combination of the nanofillers was demonstrated. The results obtained can become a platform in the design of PI-based engineering materials with tailored characteristics capable of operating in extreme conditions. Full article

Bismuth vanadate (BiVO₄) is one of the best bismuth-based semiconducting materials because of its narrow band gap energy, good visible light absorption, unique physical and chemical characteristics, and non-toxic nature. In addition, BiVO₄ with different morphologies has been synthesized and exhibited excellent visible light photocatalytic efficiency in the degradation of various organic pollutants, including volatile organic compounds (VOCs). Nevertheless, the commercial scale utilization of BiVO₄ is significantly limited because of the poor separation (faster recombination rate) and transport ability of photogenerated electron–hole pairs. So, engineering/modifications of BiVO₄ materials are performed to enhance their structural, electronic, and morphological properties. Thus, this review article aims to provide a critical overview of advanced oxidation processes (AOPs), various semiconducting nanomaterials, BiVO₄ synthesis methodologies, engineering of BiVO₄ properties through making binary and ternary nanocomposites, and coupling with metals/non-metals and metal nanoparticles and the development of Z-scheme type nanocomposites, etc., and their visible light photocatalytic efficiency in VOCs degradation. In addition, future challenges and the way forward for improving the commercial-scale application of BiVO₄-based semiconducting nanomaterials are also discussed. Thus, we hope that this review is a valuable resource for designing BiVO₄-based nanocomposites with superior visible-light-driven photocatalytic efficiency in VOCs degradation. Full article

As a typical binary transition metal oxide, ZnFe₂O₄ has attracted considerable attention for supercapacitor electrodes due to its high theoretical specific capacitance. However, the reported synthesis processes of ZnFe₂O₄ are complicated and ZnFe₂O₄ nanoparticles are easily agglomerated, leading to poor cycle life and unfavorable capacity. Herein, a facile microwave hydrothermal process was used to prepare ZnFe₂O₄/reduced graphene oxide (rGO) nanocomposites in this work. The influence of rGO content on the morphology, structure, and electrochemical performance of ZnFe₂O₄/rGO nanocomposites was systematically investigated. Due to the uniform distribution of ZnFe₂O₄ nanoparticles on the rGO surface and the high specific surface area and rich pore structures, the as-prepared ZnFe₂O₄/rGO electrode with 44.3 wt.% rGO content exhibits a high specific capacitance of 628 F g⁻¹ and long cycle life of 89% retention over 2500 cycles at 1 A g⁻¹. This work provides a new process for synthesizing binary transition metal oxide and developing a new strategy for realizing high-performance composites for supercapacitor electrodes. Full article

In this study, a novel biomass adsorbent based on activated carbon incorporated with sulfur-based binary metal oxides layered nanoparticles (SML-AC), including sulfur (S₂), manganese (Mn), and tin (Sn) oxide synthesized via the solvothermal method. The newly synthesized SML-AC was studied using FTIR, FESEM, EDX, and BET to determine its functional groups, surface morphology, and elemental composition. Hence, the BET was performed with an appropriate specific surface area for raw AC (356 m²·g⁻¹) and modified AC-SML (195 m²·g⁻¹). To prepare water samples for ICP-OES analysis, the suggested nanocomposite was used as an efficient adsorbent to remove lead (Pb²⁺), cadmium (Cd²⁺), chromium (Cr³⁺), and vanadium (V⁵⁺) from oil-rich regions. As the chemical structure of metal ions is influenced by solution pH, this parameter was considered experimentally, and pH 4, dosage 50 mg, and time 120 min were found to be the best with high capacity for all adsorbates. At different experimental conditions, the AC-SML provided a satisfactory adsorption capacity of 37.03–90.09 mg·g⁻¹ for Cd²⁺, Pb²⁺, Cr^3+, and V⁵⁺ ions. The adsorption experiment was explored, and the method was fitted with the Langmuir model (R² = 0.99) as compared to the Freundlich model (R² = 0.91). The kinetic models and free energy (<0.45 KJ·mol⁻¹) parameters demonstrated that the adsorption rate is limited with pseudo-second order (R² = 0.99) under the physical adsorption mechanism, respectively. Finally, the study demonstrated that the AC-SML nanocomposite is recyclable at least five times in the continuous adsorption–desorption of metal ions. Full article

Herein we present a facile synthesis of the graphene oxide-decorated binary transition metal oxides of Bi₂O₃ and MnO₂ nanocomposites (Bi₂O₃/MnO₂/GO) and their applications in the voltammetric detection of lead ions (Pb²⁺) in water samples. The surface morphologies, crystal structures, electroactive surface area, and charge transferred resistance of the Bi₂O₃/MnO₂/GO nanocomposites were investigated through the scanning electron microscopy (SEM), power X-ray diffraction (XRD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques, respectively. The Bi₂O₃/MnO₂/GO nanocomposites were further decorated onto the surface of a glassy carbon electrode (GCE), and Pb²⁺ was quantitatively analyzed by using square-wave anodic stripping voltammetry (SWASV). We explored the effect of the analytical parameters, including deposition potential, deposition time, and solution pH, on the stripping peak current of Pb²⁺. The Bi₂O₃/MnO₂/GO nanocomposites enlarged the electroactive surface area and reduced the charge transferred resistance by significant amounts. Moreover, the synergistic enhancement effect of MnO₂, Bi₂O₃ and GO endowed Bi₂O₃/MnO₂/GO/GCE with extraordinary electrocatalytic activity toward Pb²⁺ stripping. Under optimal conditions, the Bi₂O₃/MnO₂/GO/GCE showed a broad linear detection range (0.01–10 μM) toward Pb²⁺ detection, with a low limit of detection (LOD, 2.0 nM). The proposed Bi₂O₃/MnO₂/GO/GCE electrode achieved an accurate detection of Pb²⁺ in water with good recoveries (95.5–105%). Full article

Herein, this report uses Co₃O₄ nanoneedles to decorate Mo-Co₃O₄ nanosheets over Ni foam, which were fabricated by the hydrothermal route, in order to create a supercapacitor material which is compared with its counterparts. The surface morphology of the developed material was investigated through scanning electron microscopy and the structural properties were evaluated using XRD. The charging storage activities of the electrode materials were evaluated mainly by cyclic voltammetry and galvanostatic charge-discharge investigations. In comparison to binary metal oxides, the specific capacities for the composite Co₃O₄@Mo-Co₃O₄ nanosheets and Co₃O₄ nano-needles were calculated to be 814, and 615 C g⁻¹ at a current density of 1 A g⁻¹, respectively. The electrode of the composite Co₃O₄@Mo-Co₃O₄ nanosheets displayed superior stability during 4000 cycles, with a capacity of around 90%. The asymmetric Co₃O₄@Mo-Co₃O₄//AC device achieved a maximum specific energy of 51.35 Wh Kg⁻¹ and power density of 790 W kg⁻¹. The Co₃O₄@Mo-Co₃O₄//AC device capacity decreased by only 12.1% after 4000 long GCD cycles, which is considerably higher than that of similar electrodes. All these results reveal that the Co₃O₄@Mo-Co₃O₄ nanocomposite is a very promising electrode material and a stabled supercapacitor. Full article

This review presents recent advances in the non-enzymatic electrochemical detection and quantification of pesticides, focusing on the use of nanomaterial-based electrode modifiers and their corresponding analytical response. The use of bare glassy carbon electrodes, carbon paste electrodes, screen-printed electrodes, and other electrodes in this research area is presented. The sensors were modified with single nanomaterials, a binary composite, or triple and multiple nanocomposites applied to the electrodes’ surfaces using various application techniques. Regardless of the type of electrode used and the class of pesticides analysed, carbon-based nanomaterials, metal, and metal oxide nanoparticles are investigated mainly for electrochemical analysis because they have a high surface-to-volume ratio and, thus, a large effective area, high conductivity, and (electro)-chemical stability. This work demonstrates the progress made in recent years in the non-enzymatic electrochemical analysis of pesticides. The need for simultaneous detection of multiple pesticides with high sensitivity, low limit of detection, high precision, and high accuracy remains a challenge in analytical chemistry. Full article

This paper presents for the first time a successful fabrication of ternary ZnO/TiO₂/Ag nanocomposites consisting of zinc oxide (ZnO), titania (TiO₂) and silver (Ag) nanoparticles (NPs) synthesised using Morinda citrifolia fruit (MCF) extract. ZnONPs were synthesised using the co-precipitation method, and TiO₂ and Ag were introduced into the precursor solutions under microwave irradiation to obtain ZnO/TiO₂/Ag nanocomposites (NCs). This material demonstrated enhanced bactericidal effect towards bacterial pathogens compared to that of the binary TiO₂/Ag, Ag and TiO₂ alone. In vitro cytotoxicity results of the as-synthesised ZnO/TiO₂/AgNCs on RAW 264.7 macrophages and A549 cell lines revealed a negative role in cytotoxicity, but contributed astoundingly towards antimicrobials as compared of Ag alone and binary Ag/TiO₂. This study shows that the resultant ternary metal/bi-semiconductor nanocomposites may provide a therapeutic strategy for the eradication of bacterial pathogens without affecting the healthy mammalian cells. Full article

The sewage discharge of industrial wastewater seriously pollutes the water source and rivers, which is very harmful to the health of humans and wildlife. Among those methods for treating wastewater, photocatalysis is a sustainable and environmental-friendly technique for removing the organic pollutants with no secondary pollution. As a popular photocatalyst, graphene/metal oxide nanocomposites have been widely reported in the photocatalysis field. In this review, the recent progress of graphene/metal oxide composites including binary and ternary composites is summarized in detail. The synthesis, microstructure design, and application performance of graphene/TiO₂, graphene/ZnO, graphene/SnO₂, graphene/WO₃, graphene/Fe₂O₃, and graphene/Cu₂O composites are introduced firstly. Then, the synthesis, the selection of components, and the performance of various ternary composites are summarized specifically, including graphene/TiO₂-, graphene/ZnO-, graphene/SnO₂-, graphene/Cu₂O-, graphene/Fe_xO_y-, and graphene/Bi-containing ternary composites. At last, the possible research directions of graphene/metal oxide nanocomposites are put forward. The main purpose is to provide a theoretical guidance for designing high-performance graphene/metal oxide photocatalysts for wastewater treatment. Full article

NiCo₂O₄ nanoleaf arrays (NCO NLAs) and NiCo₂O₄/NiCO₂O₄ nanofile arrays (NCO/NCO NFAs) material was fabricated on flexible nickel foam (NF) using a facile hydrothermal approach. The electrochemical performance, including the specific capacitance, charge/discharge cycles, and lifecycle of the material after the hydrothermal treatment, was assessed. The morphological and structural behaviors of the NF@NCO NLAs and NF@NCO/NCO NFAs electrodes were analyzed using a range of analysis techniques. The as-obtained nanocomposite of the NF@NCO/NCO NFAs material delivered outstanding electrochemical performance, including an ultrahigh specific capacitance (Cs) of 2312 F g⁻¹ at a current density of 2 mA cm⁻², along with excellent cycling stability (98.7% capacitance retention after 5000 cycles at 5 mA cm⁻²). These values were higher than those of NF@NCO NLAs (Cs of 1950 F g⁻¹ and 96.3% retention). The enhanced specific capacitance was attributed to the large electrochemical surface area, which allows for higher electrical conductivity and rapid transport between the electrons and ions as well as a much lower charge-transfer resistance and superior rate capability. These results clearly show that a combination of two types of binary metal oxides could be favorable for improving electrochemical performance and is expected to play a major role in the future development of nanofile-like composites (NF@NCO/NCO NFAs) for supercapacitor applications. Full article