Highly sensitive detection of environmental toxic fenitrothion in fruits and water using a porous graphene oxide nanosheets based disposable sensor.

Monitoring fenitrothion (FNT) residues in food and the environment is crucial due to its high environmental toxicity. In this study, we developed a sensitive, reliable electrochemical method for detecting FNT by using screen-printed carbon electrodes (SPCE) modified with porous graphene oxide (PGO) nanosheets. PGO surface properties have been meticulously characterized using advanced spectroscopic techniques. Electrochemical impedance spectroscopy and cyclic voltammetry were used to test the electrochemical properties of the PGO-modified sensor. The PGO-modified sensor exhibited remarkable sensitivity, achieving a detection limit as low as 0.061 µM and a broad linear range of 0.02-250 µM. Enhanced performance is due to PGO's high surface area and excellent electrocatalytic properties, which greatly improved electron transfer. Square wave voltammetry was used to demonstrate the sensor's efficacy as a real-time, on-site monitoring tool for FNT residues in fruit and water. The outstanding performance of the PGO/SPCE sensor underscores its applicability in ensuring food safety and environmental protection.

Bifunctional vanadium doped mesoporous Co3O4 on nickel foam towards highly efficient overall urea and water splitting in the alkaline electrolyte.

Developing more active and stable electrode materials for oxygen evolution reaction (OER) and urea oxidation reaction (UOR) is necessary for electrocatalytic water and urea oxidation which can be used to generate hydrogen. Here, a low-cost vanadium-doped mesoporous cobalt oxide on Ni foam (V/meso-Co/NF) electrodes are obtained via the grouping of an in-situ citric acid (CA)-assisted evaporation-induced self-assembly (EISA) method and electrophoretic deposition process, and work as highly efficient and long-lasting electrocatalytic materials for OER/UOR. In particular, V/meso-Co/NF electrodes require 329 mV overpotential to maintain a 50 mA/cm2, with exceptional long-term durability of 30 h. Interestingly, V/meso-Co/NF also exhibits excellent electrocatalytic UOR performance, reaching 50 and 100 mA/cm2 versus RHE at low potentials of 1.34 and 1.35 V, respectively. By employing the V/meso-Co/NF materials as both the anode and cathode, this urea electrolysis assembly V/meso-Co/NF-5 (+,-) reaches current densities of 100 mA cm-2 at 1.62 V in KOH/urea, which is nearly 340 mV lesser than classical water electrolysis. The V/meso-Co/NF-5 electrocatalysts also exhibit remarkable durability for electrocatalytic OERs and UORs. The obtained findings revealed that the synthesized V/meso-Co/NF might be a promising electrode materials for overall urea-rich wastewater management and H2 generation from wastewater.

A review on ZnO nanostructured materials: energy, environmental and biological applications.

Zinc oxide (ZnO) is an adaptable material that has distinctive properties, such as high-sensitivity, large specific area, non-toxicity, good compatibility and a high isoelectric point, which favours it to be considered with a few exceptions. It is the most desirable group of nanostructure as far as both structure and properties. The unique and tuneable properties of nanostructured ZnO shows excellent stability in chemically as well as thermally stable n-type semiconducting material with wide applications such as in luminescent material, supercapacitors, battery, solar cells, photocatalysis, biosensors, biomedical and biological applications in the form of bulk crystal, thin film and pellets. The nanosized materials exhibit higher dissolution rates as well as higher solubility when compared to the bulk materials. This review significantly focused on the current improvement in ZnO-based nanomaterials/composites/doped materials for the application in the field of energy storage and conversion devices and biological applications. Special deliberation has been paid on supercapacitors, Li-ion batteries, dye-sensitized solar cells, photocatalysis, biosensors, biomedical and biological applications. Finally, the benefits of ZnO-based materials for the utilizations in the field of energy and biological sciences are moreover consistently analysed.

Enhanced Electrocatalytic Oxygen Reduction Reaction of TiO2 Nanotubes by Combining Surface Oxygen Vacancy Engineering and Zr Doping.

This work examines the cooperative effect between Zr doping and oxygen vacancy engineering in anodized TiO2 nanotubes (TNTs) for enhanced oxygen reduction reactions (ORRs). Zr dopant and annealing conditions significantly affected the electrocatalytic characteristics of grown TNTs. Zr doping results in Zr4+ substituted for Ti4+ species, which indirectly creates oxygen vacancy donors that enhance charge transfer kinetics and reduce carrier recombination in TNT bulk. Moreover, oxygen vacancies promote the creation of unsaturated Ti3+(Zr3+) sites at the surface, which also boosts the ORR interfacial process. Annealing at reductive atmospheres (e.g., H2, vacuum) resulted in a larger increase in oxygen vacancies, which greatly enhanced the ORR activity. In comparison to bare TNTs, Zr doping and vacuum treatment (Zr:TNT-Vac) significantly improved the conductivity and activity of ORRs in alkaline media. The finding also provides selective hydrogen peroxide production by the electrochemical reduction of oxygen.

Photoelectrochemical Performance of Strontium Titanium Oxynitride Photo-Activated with Cobalt Phosphate Nanoparticles for Oxidation of Alkaline Water.

Photoelectrochemical (PEC) solar water splitting is favourable for transforming solar energy into sustainable hydrogen fuel using semiconductor electrodes. Perovskite-type oxynitrides are attractive photocatalysts for this application due to their visible light absorption features and stability. Herein, strontium titanium oxynitride (STON) containing anion vacancies of SrTi(O,N)3-δ was prepared via solid phase synthesis and assembled as a photoelectrode by electrophoretic deposition, and their morphological and optical properties and PEC performance for alkaline water oxidation are investigated. Further, cobalt-phosphate (CoPi)-based co-catalyst was photo-deposited over the surface of the STON electrode to boost the PEC efficiency. A photocurrent density of ~138 µA/cm at 1.25 V versus RHE was achieved for CoPi/STON electrodes in presence of a sulfite hole scavenger which is approximately a four-fold enhancement compared to the pristine electrode. The observed PEC enrichment is mainly due to the improved kinetics of oxygen evolution because of the CoPi co-catalyst and the reduced surface recombination of the photogenerated carriers. Moreover, the CoPi modification over perovskite-type oxynitrides provides a new dimension for developing efficient and highly stable photoanodes in solar-assisted water-splitting reactions.

Enhanced electrocatalytic oxygen redox reactions of iron oxide nanorod films by combining oxygen vacancy formation and cobalt doping.

A synergistic effect of Co-doping and vacuum-annealing on electrochemical redox reactions of iron oxide films is demonstrated in the present work. In this research, a series of defect-rich iron oxy/hydroxide nanorod arrays: α-FeOOH, Fe2O3, and FeOx nanorod thin film catalysts were synthesized via a hydrothermal approach followed by thermal and vacuum treatments. Besides, a cobalt doping process was employed to prepare the thin film of Co-doped FeOx nanorods. The morphology, crystallinity, and electrochemical activities of Co-doped oxygen-deficient FeOx (Co-FeOx/FTO) show strong correlations with metal concentration and thermal treatments. The electrochemical measurements demonstrated that the as-deposited Co-doped FeOx NR catalyst could achieve a maximum OER current of 30 mA cm-2, which was six times greater than that recorded by as-deposited Co-doped FeOOH NR catalysts (5.7 mA cm-2) at 1.65 V vs. RHE, confirming the superior electrocatalytic OER activity at the as-deposited Co-doped FeOx NR catalyst after cobalt doping. It is believed that these results are attributed to two factors: the synergistic effect of Co doping and the defect-rich nature of FeOx nanorod catalysts that are used in sustainable energy systems.

Recent Advances in Biodegradable Polymers and Their Biological Applications: A Brief Review.

The rising significance of the field of biopolymers has driven the rapid progress of this distinctive class of polymeric materials in the past decades. Biodegradable polymers have acquired much attention because they play an essential role in humans' lives due to their specific tunable electrical conductivity and biodegradability characteristics, making them fascinating in many applications. Herein, we debated the recent progress in developing biodegradable polymers and their applications. Initially, we introduce the basics of conducting and biodegradable polymers, trailed by debates about the effective strategies currently used to develop biopolymers. Special importance will focus on the uses of biodegradable polymers in drug delivery and tissue engineering, as well as wound healing, demonstrating the recent findings, and uses of several biodegradable polymers in modern biological uses. In this review, we have provided comprehensive viewpoints on the latest progress of the challenges and future prospects involving biodegradable polymers' advancement and commercial applications.

Toxic heavy metal cadmium removal using chitosan and polypropylene based fiber composite.

The aim of the present work was to evaluate the performance of polypropylene (PP)/sisal fiber (SF)/banana fiber (BF) and chitosan-based hybrid (chitosan(CS)/SF)/BF) composite materials for the adsorptive removal of cadmium (Cd) ions from water waste. Polypropylene is harnessed for its importance in forming strong composite materials for various applications. Chitosan biopolymer encloses a great deal of amino and hydroxyl groups, which provide effective removal of Cd ions from wastewater. The batch adsorption studies proved that the removal of Cd ions was pH-dependent and attained optimum at pH 5.5 for both the composites. Langmuir and Freundlich models were applied for the obtained experimental values. Based on the R2 values, it was evidenced that the adsorption process was best fitted with the Freundlich isotherm than Langmuir. The sorption capacity of CS/SF/BF hybrid composite (Cmax = 419 mg/g) is higher than PP/SF/BF composite (Cmax = 304 mg/g), and allows multilayer adsorption. Kinetics studies revealed that the pseudo-second-order model was followed during the removal of Cd ion from wastewater. The overall evaluation proved that though both the adsorbents are suitable for the removal of Cd ions, the efficiency of CS-based ternary composite material is better than PP-based composite.

Nanofiber NiMoO4/g-C3N4 Composite Electrode Materials for Redox Supercapacitor Applications.

NiMoO4/g-C3N4 was fabricated by a hydrothermal method and used as an electrode material in a supercapacitor. The samples were characterized by XRD, FTIR, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to study the physical and structural properties of the as-prepared NiMoO4/g-C3N4 material. The electrochemical responses of pristine NiMoO4 and the NiMoO4/g-C3N4 nanocomposite material were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). From the CD studies, the NiMoO4/g-C3N4 nanocomposite revealed a higher maximum specific capacitance (510 Fg-1) in comparison to pristine NiMoO4 (203 Fg-1). In addition, the NiMoO4/g-C3N4 composite electrode material exhibited high stability, which maintained up to 91.8% capacity even after 2000 charge-discharge cycles. Finally, NiMoO4/g-C3N4 was found to exhibit an energy density value of 11.3 Whkg-1. These findings clearly suggested that NiMoO4/g-C3N4 could be a suitable electrode material for electrochemical capacitors.

Mesoporous Tungsten Trioxide Photoanodes Modified with Nitrogen-Doped Carbon Quantum Dots for Enhanced Oxygen Evolution Photo-Reaction.

Nanostructured photoanodes are attractive materials for hydrogen production via water photo-electrolysis process. This study focused on the incorporation of carbon quantum dots doped with nitrogen as a photosensitizer into mesoporous tungsten trioxide photoanodes (N-CQD/meso-WO3) using a surfactant self-assembly template approach. The crystal structure, composition, and morphology of pure and N-CQD- modified mesoporous WO3 photoanodes were investigated using scanning electron and transmission microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Due to their high surface area, enhanced optical absorption, and charge-carrier separation and transfer, the resulting N-CQD/meso-WO3 photoanodes exhibited a significantly enhanced photocurrent density of 1.45 mA cm-2 at 1.23 V vs. RHE under AM 1.5 G illumination in 0.5 M Na2SO4 without any co-catalysts or sacrificial reagent, which was about 2.23 times greater than its corresponding pure meso-WO3. Moreover, the oxygen evolution onset potential of the N-CQD/meso-WO3 photoanodes exhibited a negative shift of 95 mV, signifying that both the charge-carrier separation and transfer processes were promoted.

3D nanorhombus nickel nitride as stable and cost-effective counter electrodes for dye-sensitized solar cells and supercapacitor applications.

Transition metal nitride based materials have attracted significant interest owing to their excellent properties and multiple applications in the field of electrochemical energy conversion and storage devices. Herein we synthesize 3D nanorhombus nickel nitride (Ni3N) thin films by adopting a reactive radio frequency magnetron sputtering process. The as-deposited 3D nano rhombus Ni3N thin films were utilized as cost-effective electrodes in the fabrication of supercapacitors (SCs) and dye-sensitized solar cells (DSSCs). The structure, phase formation, surface morphology and elemental composition of the as-deposited Ni3N thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM). The electrochemical supercapacitive performance of the Ni3N thin films was examined by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques, in 3 M KOH supporting electrolyte. The areal capacitance of the Ni3N thin film electrode obtained from CV analysis was 319.5 mF cm-2 at a lower scan rate of 10 mV s-1. Meanwhile, the Ni3N thin film showed an excellent cyclic stability and retained 93.7% efficiency of its initial capacitance after 2000 cycles at 100 mV s-1. Interestingly, the DSSCs fabricated with a Ni3N CE showed a notable power energy conversion efficiency of 2.88% and remarkable stability. The prominent performance of the Ni3N thin film was ascribed mainly due to good conductivity, high electrochemically active sites with excellent 3D nano rhombus structures and high electrocatalytic activity. Overall, these results demonstrate that the Ni3N electrode is capable of being considered for efficient SCs and DSSCs. This investigation also offers an essential directive for the advancement of energy storage and conversion devices.

Zinc Tantalum Oxynitride (ZnTaO2N) Photoanode Modified with Cobalt Phosphate Layers for the Photoelectrochemical Oxidation of Alkali Water.

Photoanodes fabricated by the electrophoretic deposition of a thermally prepared zinc tantalum oxynitride (ZnTaO2N) catalyst onto indium tin oxide (ITO) substrates show photoactivation for the oxygen evolution reaction (OER) in alkaline solutions. The photoactivity of the OER is further boosted by the photodeposition of cobalt phosphate (CoPi) layers onto the surface of the ZnTaO2N photoanodes. Structural, morphological, and photoelectrochemical (PEC) properties of the modified ZnTaO2N photoanodes are studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet visible (UV-Vis) diffuse reflectance spectroscopy, and electrochemical techniques. The presence of the CoPi layer significantly improved the PEC performance of water oxidation in an alkaline sulphate solution. The photocurrent-voltage behavior of the CoPi-modified ZnTaO2N anodes was improved, with the influence being more prominent at lower oxidation potentials. A stable photocurrent density of about 2.3 mA·cm-2 at 1.23 V vs. RHE was attained upon visible light illumination. Relative to the ZnTaO2N photoanodes, an almost three-fold photocurrent increase was achieved at the CoPi/ZnTaO2N photoelectrode. Perovskite-based oxynitrides are modified using an oxygen-evolution co-catalyst of CoPi, and provide a new dimension for enhancing the photoactivity of oxygen evolution in solar-assisted water-splitting reactions.

Recent Advances in Metal Chalcogenides (MX; X = S, Se) Nanostructures for Electrochemical Supercapacitor Applications: A Brief Review.

Supercapacitors (SCs) have received a great deal of attention and play an important role for future self-powered devices, mainly owing to their higher power density. Among all types of electrical energy storage devices, electrochemical supercapacitors are considered to be the most promising because of their superior performance characteristics, including short charging time, high power density, safety, easy fabrication procedures, and long operational life. An SC consists of two foremost components, namely electrode materials, and electrolyte. The selection of appropriate electrode materials with rational nanostructured designs has resulted in improved electrochemical properties for high performance and has reduced the cost of SCs. In this review, we mainly spotlight the non-metallic oxide, especially metal chalcogenides (MX; X = S, Se) based nanostructured electrode materials for electrochemical SCs. Different non-metallic oxide materials are highlighted in various categories, such as transition metal sulfides and selenides materials. Finally, the designing strategy and future improvements on metal chalcogenide materials for the application of electrochemical SCs are also discussed.

A low cost additive-free facile synthesis of BiFeWO6/BiVO4 nanocomposite with enhanced visible-light induced photocatalytic activity.

In this study, visible light driven BiFeWO6/BiVO4 nanocomposite was synthesized via simple additive-free wet-chemical process. Various physicochemical characterization methods such as X-ray diffraction (XRD), fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electrons microscopy (TEM), energy dispersive spectroscopy (EDS) spectra, UV visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and photoelectrochemical measurements were performed to examine the structure, surface morphology, electrochemical and optical behavior of the synthesized material. The photocatalytic performances of the as-synthesized materials were assessed by the photodegradation of methylene blue (MB) in visible-light illumination. The optimum BiFeWO6/BiVO4-2 nanocomposite has shown 95% degradation efficiency of (MB) after 90min. This is about 10-folds higher than that of pristine bismuth vanadate (BiVO4). This enhancement of photocatalytic performances is credited to the photogenerated electrons transfer from BiVO4 to BiFeWO6 catalyst surface and thereby reduced the recombination process. The higher photocatalytic activity, long-term stability and recyclability results have revealed that the BiFeWO6/BiVO4 nanocomposite could be an auspicious material for the elimination of organic contaminants present in the ecosystem. Moreover, a probable mechanism for the catalytic degradation of MB dye over BiFeWO6/BiVO4 system is also proposed based on experimental results.

Phyllanthus emblica seed extract mediated synthesis of PdNPs against antibacterial, heamolytic and cytotoxic studies.

Ecofriendly synthesis of Palladium nanoparticles (PdNPs) were achieved using Phyllanthus emblica (P. emblica) seeds as reducing agent. Further the ecofriendly synthesized PdNPs were subjected for various analytical techniques like UV-Vis, FT-IR, XRD, Zeta potential, SEM and TEM. The results indicated that green synthesized PdNPs were spherical in shape with average particle size of 28±2nm with moderate stability. Further the synthesized PdNPs and extract were subjected for its antibacterial studies against various disease causing pathogens by agar well diffusion method. Seed extract resulted in 8.9±1.46mm against B. subtilis and PdNPs showed 9.6±1.10mm against S. aureus and synthesized PdNPs and extract were tested for hemolytic which resulted in 20% and 10% respectively. Toxicity studies were done against Artemia salina (A. salina). The LC50 value of green synthesized P. emblica capped PdNPs and the P. emblica seed extract were found to be less toxic for A. salina with a value of 1.00µg/mL and 1.25µg/mL. In addition samples were checked for in vitro cytotoxicity assays on HeLa cell lines.