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The discharge of toxic dye effluents from industry is a major concern for environmental pollution and toxicity. These toxic dyes can be efficiently removed from waste streams using a photocatalysis process involving visible light. Due to its simple synthesis procedure, inexpensive precursor, and robust stability, graphitic carbon nitride (g-C 3 N 4 , or CN) has been used as a visible light responsive catalyst for the degradation of dyes with mediocre performance because it is limited by its low visible light harvesting capability due to its wide bandgap and fast carrier recombination rate. To overcome these limitations and enhance the performance of g-C 3 N 4 , it was coupled with a narrow bandgap copper tin sulfide (CTS) semiconductor to form a p-n heterojunction. CTS and g-C 3 N 4 were selected due to their good stability, low toxicity, ease of synthesis, layered sheet/plate-like morphology, and relatively abundant precursors. Accordingly, a series of copper tin sulfide/graphitic carbon nitride nanocomposites (CTS/g-C 3 N 4 ) with varying CTS contents were successfully synthesized via a simple two-step process involving thermal pyrolysis and coprecipitation for visible-light-induced photocatalytic degradation of methyl orange (MO) dye. The photocatalytic activity results showed that the 50%(wt/wt) CTS/g-C 3 N 4 composite displayed a remarkable degradation efficiency of 95.6% for MO dye under visible light illumination for 120 min, which is higher than that of either pristine CTS or g-C 3 N 4 . The improved performance is attributed to the extended light absorption range (due to the optimized bandgap), effective suppression of photoinduced electron-hole recombination, and improved charge transfer that arose from the formation of a p-n heterojunction, as evidenced by electrochemical impedance spectroscopy (EIS), photocurrent, and photoluminescence results. Moreover, the results of the reusability study showed that the composite has excellent stability, indicating its potential for the degradation of MO and other toxic organic dyes from waste streams., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Copper tin sulfide, Cu 4 SnS 4 (CTS), a ternary transition-metal chalcogenide with unique properties, including superior electrical conductivity, distinct crystal structure, and high theoretical capacity, is a potential candidate for supercapacitor (SC) electrode materials. However, there are few studies reporting the application of Cu 4 SnS 4 or its composites as electrode materials for SCs. The reported performance of the Cu 4 SnS 4 electrode is insufficient regarding cycle stability, rate capability, and specific capacity; probably resulting from poor electrical conductivity, restacking, and agglomeration of the active material during continued charge-discharge cycles. Such limitations can be overcome by incorporating graphene as a support material and employing a binder-free, facile, electrodeposition technique. This work reports the fabrication of a copper tin sulfide-reduced graphene oxide/nickel foam composite electrode (CTS-rGO/NF) through stepwise, facile electrodeposition of rGO and CTS on a NF substrate. Electrochemical evaluations confirmed the enhanced supercapacitive performance of the CTS-rGO/NF electrode compared to that of CTS/NF. A remarkably improved specific capacitance of 820.83 F g -1 was achieved for the CTS-rGO/NF composite electrode at a current density of 5 mA cm -2 , which is higher than that of CTS/NF (516.67 F g -1 ). The CTS-rGO/NF composite electrode also exhibited a high-rate capability of 73.1% for galvanostatic charge-discharge (GCD) current densities, ranging from 5 to 12 mA cm -2 , and improved cycling stability with over a 92% capacitance retention after 1000 continuous GCD cycles; demonstrating its excellent performance as an electrode material for energy storage applications, encompassing SCs. The enhanced performance of the CTS-rGO/NF electrode could be attributed to the synergetic effect of the enhanced conductivity and surface area introduced by the inclusion of rGO in the composite., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

In this study, Ce 4+ -doped Ni-Al mixed oxides (NACO) were synthesized and comprehensively characterized for their potential application in fluoride adsorption. NACOs were examined using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM), revealing a sheet-like morphology with a nodular appearance. X-ray diffraction (XRD) analysis confirmed the formation of mixed oxides of cubic crystal structure, with characteristic planes (111), (200), and (220) at 2 θ values of 37.63°, 43.61°, and 63.64°, respectively. Further investigations using X-ray Photoelectron Spectroscopy (XPS) identified the presence of elements such as Ni, Al, Ce, and O with oxidation states +2, +3, +4, and -2, respectively. The Brunauer-Emmett-Teller (BET) analysis indicated that NACO followed a type IV physisorption isotherm, suggesting favorable surface adsorption characteristics. The adsorption kinetics was studied, and the experimental data exhibited a good suit to both pseudo-first order and pseudo-second order, as indicated by high R 2 values. Moreover, the Freundlich isotherm model demonstrated a good fit to the experimental data. The result also revealed that NACO has a maximum capacity for adsorption ( q max ) of 132 mg g -1 . Thermodynamic studies showed that fluoride adsorption onto NACO was feasible and spontaneous. Additionally, NACO exhibited excellent regeneration capabilities, as evidenced by a remarkable 75.71% removal efficiency at the sixth regeneration stage, indicating sustained adsorption capacity even after multiple regeneration cycles. Overall, NACOs displayed promising characteristics for fluoride adsorption, making them potential candidates for efficient and sustainable water treatment technologies., Competing Interests: The authors of this paper assert that they have no known competing issues that could have potentially impacted the research findings presented in this study., (This journal is © The Royal Society of Chemistry.)

The present communication deals with the adsorption of tyramine neurotransmitter over the surface of pristine, Boron (B) and Silicon (Si) doped fullerenes. Density functional theory (DFT) calculations have been used to investigate tyramine adsorption on the surface of fullerenes in terms of stability, shape, work function, electronic characteristics, and density of state spectra. The most favourable adsorption configurations for tyramine have been computed to have adsorption energies of - 1.486, - 30.889, and - 31.166 kcal/mol, respectively whereas for the rest three configurations, it has been computed to be - 0.991, - 6.999, and - 8.796 kcal/mol, respectively. The band gaps for all six configurations are computed to be 2.68, 2.67, 2.06, 2.17, 2.07, and 2.14 eV, respectively. The band gap of pristine, B and Si doped fullerenes shows changes in their band gaps after adsorption of tyramine neurotransmitters. However, the change in band gaps reveals more in B doped fullerene rather than pristine and Si doped fullerenes. The change in band gaps of B and Si doped fullerenes leads a change in the electrical conductivity which helps to detect tyramine. Furthermore, natural bond orbital (NBO) computations demonstrated a net charge transfer of 0.006, 0.394, and 0.257e from tynamine to pristine, B and Si doped fullerenes., (© 2023. The Author(s).)

Excessive fluoride removal from aqueous solutions is of utmost importance as it has an adverse impact on human health. This study investigates the defluoridation efficiency of a novel nano-sized Ce +4 -doped Ni/Al layered double hydroxide (Ni-Al-Ce LDH) for aqueous solutions. The synthesized Ni-Al-Ce LDH exhibited a well-defined nanoscale plate-like morphology and a high surface area with an average size of 11.51 nm, which contributed to its enhanced fluoride adsorption capacity. XRD, SEM, HRTEM, and BET studies confirmed these characteristics. XPS analysis confirmed the presence of Ce 4+ ions within the Ni-Al LDH. The experimental results indicated that the process of defluoridation followed a pseudo-second-order model of kinetics, suggesting a chemisorption mechanism. The fluoride adsorption isotherms demonstrated well fits to the Freundlich, Langmuir, and Jovanovic models, indicating both monolayer and multilayer fluoride adsorption on the Ce-doped Ni-Al LDH. The maximum adsorption capacity was found to be 238.27 mg/g (Langmuir) and 130.73 mg/g (Jovanovic) at pH 6.0 and 25 °C. The proposed mechanisms for fluoride adsorption on the LDH include ion exchange, surface complexation, hydrogen bonding, and ligand exchange. The Ni-Al-Ce LDH nanomaterial exhibited good recyclability, maintaining 71% of the fluoride adsorption efficiency even after four consecutive cycles. This study highlights the significant role of Ce doping in improving the performance of Ni-Al LDH as a defluoridation adsorbent., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Currently, plant extract-mediated synthesized metal oxide nanoparticles (MO NPs) have played a substantial role in biological applications. Hence, this study focused on the eco-benign one-pot synthesis of bimetallic ZnO-CuO nanoparticles (ZC NPs) using the leaf extract of Artemisia abyssinica (LEAA) and evaluations of their anticancer, antioxidant, and molecular binding efficacy. The optical absorption peak at 380 nm from UV-visible (UV-vis) analysis revealed the formation of ZC NPs. X-ray diffraction (XRD) results revealed the fabrication of mixed-phase crystals with hexagonal and monoclinic structures of ZC NPs with an average crystallite size of 14 nm. Moreover, the biosynthesis of ZC NPs with a spherical morphology and an average particle size of 13.09 nm was confirmed by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and transmission electron microscopy (TEM) results. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA/DTA) spectroscopy confirmed the involvement of functional groups from LEAA during the synthesis of ZC NPs. ZC NPs have exhibited the ferric ion reducing power (FRAP) with an absorbance of 1.826 ± 0.00 at 200 μg/mL and DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical scavenging activity of 95.71 ± 0.02% at 200 μg/mL with an IC50 value of 3.28 μg/mL. Moreover, ZC NPs had shown a promising in vitro anticancer activity of 89.20 ± 0.038 at 500 μg/mL with an IC50 value of 33.12 μg/mL against breast cancer (MCF-7) cell lines. Likewise, ZC NPs have shown strong binding affinity (-8.50 kcal/mol) against estrogen receptor α (ERα) in molecular docking simulations. These findings suggested that the biosynthesized ZC NPs could be used as promising antioxidant and anticancer drug candidates, particularly for breast cancer ailments. However, the in vivo cytotoxicity test will be recommended to ensure further use of ZC NPs., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Here, the structural, optical, and adsorptive behaviors of Ni 0.075-x Mn x Al 0.025 (OH) 2 (CO 3 ) 0.0125 ·yH 2 O (Ni-Mn/Al) layered double hydroxides (LDHs) are investigated to capture fluoride from aqueous media. The 2D mesoporous plate-like Ni-Mn/Al LDHs are successfully prepared via a co-precipitation method. The molar ratio of divalent to trivalent cations is maintained at 3:1 and the pH at 10. The X-ray diffraction (XRD) results confirm that the samples consist of pure LDH phases with a basal spacing of 7.66 to 7.72 Å, corresponding to the (003) planes at 2 θ of 11.47 o and the average crystallite sizes of 4.13 to 8.67 nm. The plate-like Mn-doped Ni-Al LDH consists of many superimposed nanosheets with a size of 9.99 nm. Energy-dispersive X-ray and X-ray photoelectron spectroscopies confirm the incorporation of Mn 2+ into the Ni-Al LDH. UV-vis diffuse reflectance spectroscopy results indicate that incorporating Mn 2+ into LDH enhances its interaction with light. The experimental data from the batch fluoride adsorption studies are subjected to kinetic models such as pseudo-first order and pseudo-second order. The kinetics of fluoride retention on Ni-Mn/Al LDH obey the pseudo-second-order model. The Temkin equation well describes the equilibrium adsorption of fluoride. The results from the thermodynamic studies also indicate that fluoride adsorption is exothermic and spontaneous., Competing Interests: The authors declare no conflict of interest., (© 2023 The Authors. Global Challenges published by Wiley‐VCH GmbH.)

Zinc oxide (ZnO) is a fascinating semiconductor material with many applications such as adsorption, photocatalysis, sensor, and antibacterial activities. By using a poly (vinyl alcohol) (PVA) polymer as a capping agent and metal oxides (iron and manganese) as a couple, the porous PVA-aided Zn/Fe/Mn ternary oxide nanocomposite material (PTMO-NCM) was synthesized. The thermal, optical, crystallinity, chemical bonding, porosity, morphological, charge transfer properties of the synthesized materials were confirmed by DTG/DSC, UV-Vis-DRS, XRD, FT-IR, BET, SEM-EDAX/TEM-HRTEM-SAED, and CV/EIS/amperometric analytical techniques, respectively. The PTMO-NCM showed an enhanced surface area and charge transfer capability, compared to ZnO. Using the XRD pattern and TEM image analysis, the crystalline size of the materials was confirmed to be in the nanometer range. The porosity and superior charge transfer capabilities of the PTMO-NCM were confirmed from the BET, HRTEM (IFFT)/SAED, and CV/EIS analysis. The adsorption kinetics (adsorption reaction/adsorption diffusion) and adsorption isotherm test confirmed the presence of a chemisorption type of adsorbate/methylene blue dye-adsorbent/PTMO-NCM interaction. The photocatalytic performance was tested on the Congo red and Acid Orange-8 dyes. The superior ascorbic acid sensing capability of the material was understood from CV and amperometric analysis. The noble antibacterial activities of the material were also confirmed on both gram-negative and gram-positive bacteria.

Zinc oxide is one of the novel metal oxides utilized for diverse applications. The sol-gel and unintended self-propagation procedures were applied to synthesize the porous and high surface area ZnO-based metal oxide nanocomposite. The p-type manganese(III) oxide was successfully coupled with n-type ZnO . The physical property characterization results revealed the surface area, porosity, and charge transfer capability improvement on the poly(vinyl alcohol) (PVA)-aided binary nanocomposite (PVA-ZnO/Mn 2 O 3 ), compared to ZnO. The XRD patterns and TEM image analysis validated the nanometer size range for the materials (15-60 nm). The SEM micrographs and BET spectral details have confirmed the porous nature of the PVA-ZnO/Mn 2 O 3 nanocomposite. The supporting results were obtained from the HRTEM (IFFT) and SAED pattern analyses. The EDX and HRTEM analyses were used for the confirmation of elemental composition and reality of the PVA-ZnO/Mn 2 O 3 composite, respectively. The presence of the improved charge transfer property for PVA-ZnO/Mn 2 O 3 , compared to ZnO, was evidenced from acid orange-8 dye degradation. The highest zone of inhibition (14 mm) was recorded on Escherichia coli bacteria for the uncalcined PVA-ZnO/Mn 2 O 3 nanocomposite compared to PVA, yet, less zone of inhibition compared to the calcined PVA-ZnO/Mn 2 O 3 nanocomposite. The authors recommend the formation of the couple between metal oxides by electrochemical technique analyses as a future work., Competing Interests: The authors declare no competing financial interest., (© 2020 The Authors. Published by American Chemical Society.)

Metal oxide nanomaterials are one of the preferences as antibacterial active materials. Due to its distinctive electronic configuration and suitable properties, ZnO is one of the novel antibacterial active materials. Nowadays, researchers are making a serious effort to improve the antibacterial activities of ZnO by forming a composite with the same/different bandgap semiconductor materials and doping of ions. Applying capping agents such as polymers and plant extract that control the morphology and size of the nanomaterials and optimizing different conditions also enhance the antibacterial activity. Forming a nanocomposite and doping reduces the electron/hole recombination, increases the surface area to volume ratio, and also improves the stability towards dissolution and corrosion. The release of antimicrobial ions, electrostatic interaction, reactive oxygen species (ROS) generations are the crucial antibacterial activity mechanism. This review also presents a detailed discussion of the antibacterial activity improvement of ZnO by forming a composite, doping, and optimizing different conditions. The morphological analysis using scanning electron microscopy, field emission-scanning electron microscopy, field-emission transmission electron microscopy, fluorescence microscopy, and confocal microscopy can confirm the antibacterial activity and also supports for developing a satisfactory mechanism. Graphical abstract showing the metal oxides antibacterial mechanism and the fluorescence and scanning electron microscopic images.

Magnetite and silica-coated magnetite (Fe 3 O 4 ) nanoparticles (NPs) were synthesized by water-in-oil (W/O) microemulsion method from hydrated ferric nitrate, ferrous sulfate precursors and ammonia a precipitating agent with the assistance of Tween-80 and SDS surfactants. The synthesized materials were characterized by X-ray diffraction, scanning electron microscopy, thermal analyzer, and infrared spectroscopy. X-ray diffraction pattern of Fe 3 O 4 showed that particles were phase pure with a cubic inverse spinel structure and FT-infrared spectra confirmed the presence of Fe-O bond in tetrahedral and octahedral interstitial sites. The crystallite size determined from powder XRD data with Scherer's equation was in the range of 7.3 ± 0.05 nm-10.83 ± 0.02 nm for uncoated Fe 3 O 4 and 16 ± 0.14 nm for silica-coated Fe 3 O 4 NPs. The SEM micrographs of the uncoated Fe 3 O 4 oxide revealed the agglomeration of the magnetite (Fe 3 O 4 ) particles. But the silica-coated Fe 3 O 4 oxide exhibited homogeneous distribution of particles with relatively less agglomerate of the particles. The particle size of Fe 3 O 4 NPs slightly increased with the temperature and precursor concentration. The antimicrobial activities of Fe 3 O 4 and silica-coated Fe 3 O 4 nanoparticles were tested against Gram-negative ( Escherichia coli and Pseudomonas aeruginosa ) and Gram-positive ( Staphylococcus aureus and Bacillus subtilis ) bacteria. Both Fe 3 O 4 and silica-coated Fe 3 O 4 NPs demonstrated better antimicrobial activities., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Goshu Asab et al.)