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The current world is exposed to immense classes of challenges, of which antimicrobial-caused infectious diseases have been ranked the third killer disease due to their high resistance capability. Oxidative stress is also the other problem faced by the current world. In the current study, a leaf of Foeniculum Vulgare was employed for the synthesis of silver nanoparticles (Ag NPs) within the 1:3, 1:1, and 3:1 compositions using 0.1 M of AgNO3. The calculated average crystalline size from X-ray diffraction (XRD) was found to be 12.6, 13.7, and 21.6 nm for the 1:3, 1:1, and 3:1 volume ratios, respectively. Scanning electron microscope coupled with energy dispersive spectroscopy (SEM-EDS) analysis depicts the quasi-spherical shape with an intense Ag peak at around 3.00 eV. Transmission electron microscope coupled with high-resolution transmission microscope with surface area electron diffraction pattern (TEM-HRTEM with SAED) showed spherical shaped Ag NPs. The electronic bandgap energy was calculated as 3.1, 3.2, and 3.3 eV for the 1:1, 3:1, and 1:3 volume compositions, respectively. Ag NPs show 13.5, 12.5, and 11.0 mm zones of inhibition for the 1:3, 1:1, and 3:1 ratios, respectively. The antifungal activity was found to be 16.9, 11.2, and 10.5 mm for the 3:1, 1:3 and 1:1 ratios, respectively. Lastly, the antioxidant activity was estimated to be 42.4, 28.94, and 27.39% RSA for the 1:1, 3:1, and 1:3 volume ratios respectively. All the ratios of Ag NPs showed promised antimicrobial and antioxidant activity in the presence of 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) due to the enhanced generation of reactive oxygen species (ROS). Highlights: Green Synthesis of Ag NPs within three volume ratios in the presence of Foeniculum vulgare leaf extract. Investigating the potential antibacterial, antifungal, and antioxidant activities. Comparative study of the volume ratios on the antimicrobial and antioxidant activities. [ABSTRACT FROM AUTHOR]

The current work describes the environmentally friendly green method for fabricating CaO nanoparticles (NPs) using 'tulasi’ (Ocimum sanctum) plant leaf extract as a unique fuel. The obtained CaO NPs have been characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), TEM/HRTEM (Transmission Electron Microscopy), UV–Vis spectroscope, Selected Area Electron Diffraction (SAED), and Energy Dispersive Spectroscopy (EDAX) techniques. The PXRD studies revealed the average crystallite size of 38 nm for CaO NPs and this value is in compliance with the TEM results. DRS studies revealed the energy gap of CaO as 3.20 eV. The plant-mediated CaO NPs showed good photocatalytic activities for the photodegradation of Fast Orange (FO) and Fast Blue (FB) dyes under the UV light irradiation, demonstrating high efficiency within 120 min of light irradiation. Under UV light, the CaO exhibited impressive photodegradation performance of 95.5% and 83.5% in 120 min against the FO and FB dyes. The electrochemical characteristics of CaO were studied using a carbon paste electrode in a 0.1 M NaOH solution. The green CaO NPs exhibited superior sensitivity in cyclic voltammetry tests at different scan rates when lead and lithium were utilized as analytes. The phase angle of CaO was determined to be − 47°, which is close to the behavior of an ideal capacitor (− 90°). Consequently, CaO holds potential for applications in electrochemical sensor technology. [ABSTRACT FROM AUTHOR]

This present research aimed to investigate the novel applications of synthesized La doped CuFe2O4 nanomaterial (LCF NMs) using renewable bio-fuel (Aegle Marmelos extract) by combustion process. The sensor applications were accomplished by modified electrode using LCF NMs with graphite powder and examined its excellent sensing action towards heavy metal (Lead content) and drug chemical (Paracetamol) substances. The thermodynamics of redox potential and super-capacitor behavior of LCF NMs were investigated through Cyclic Voltametric (CV) and Electrochemical Impedance Spectral (EIS) methods under specific conditions at scan rate of 1 to 5 mV/s. The heterogeneous photo-catalytic process of prepared NMs on Fast orange Red (FOR) dye-decolouration was investigated and noted its excellent degradation (91.7%) at 90 min using 20 ppm of dye solution and 40 mg of synthesized samples under Sun-light irradiation. Further, the antibacterial activity of synthesized NMs is investigated against various strains of gram positive (Bacillus subtillis) and gram negative bacteria (Pseudomonas aeruginosa), which confirms that the LCF NMs have higher activity towards gram positive bacteria with an average inhibition zone of 19 mm. This synthesized LCF NMs is a multi-functional material with stable and eco-friendly materials. [ABSTRACT FROM AUTHOR]

In the current work, orange peels were employed to prepare the activated carbon by the carbonization method at low temperature (AC-OP) using the nickel mesh for the first time. Through the use of several depiction techniques, the essential characteristics of the novel AC-OP electrode have been examined. The electrochemical behaviour of the AC-OP's electrode has been assessed. By using the scanning electron microscope, the prepared AC-OP powder was found to exhibit honeycomb shape. The energy gap (Eg) is discovered to be 2.06 eV. The electrochemical components of AC-OP powder, which is the primary active ingredient, deposited on nickel mesh act as a current collector. Electrochemical impedance spectroscopic and cyclic voltammetric methods are used to analyse nickel mesh electrodes. The hydrogen diffusion co-efficient of AC-OP electrode is found to be 9.30 × 10–5 cm2 s−1. The developed AC-OP electrode's exceptional capacitive potential was confirmed from the galvanostatic charge–discharge tests, favourable for the fabrication of supercapacitors. These cutting-edge effects might also be quantified for the utility of power storage employing reasonably cost carbon resources in many applications for energy storage. [ABSTRACT FROM AUTHOR]

Barium strontium titanate (BST) is a perovskite utilized in a variety of applications. Hence, the main aim of this research was synthesizing and characterizing BST and Mo-doped BST nanopowders so that the effect of Mo on some properties of BST was investigated. They were synthesized through a slow injection sol–gel method calcined at 800 °C. The SEM image of BST and Mo-doped BST nanopowders revealed that more agglomerated particles with the respective grain size of 40.13 and 27.00 nm, respectively, were obtained. Incorporation of Mo to BST has resulted in lowering of average crystal sizes from 23.97 to 17.84 nm, from the XRD data. The particle size of Mo-BST was also obtained from the TEM as 24.591 nm. The BET data revealed that lowering of the specific surface area from 557.9 to 54.2 m2/g was accompanied by reduction of pore volume with almost constant porous size, after the incorporation of Mo6+ to BST. From the XPS data, the binding energy of Mo3d in the BST powder was found as Mo6+ 3d5/2 (232 eV) and Mo6+ 3d3/2 (235 eV) confirming the existence of Mo on the BST perovskite which has been further supported by the EDS spectrum and Raman spectroscopy data, while the functional groups such as Mo–O, Ti–O, Ba–O, Sr–O were revealed by the FTIR spectrum in the range 400–600 cm−1. All the data supported the conclusion that Mo-doped BST has been effectively synthesized through a slow injection sol–gel method with varied properties from the pure BST. [ABSTRACT FROM AUTHOR]

In this study, spinel zinc chromite nanorods (ZnCr2O4 NRs) were successfully manipulated by a simple sol-gel auto combustion process employing urea as fuel. The sample was only required to sinter at 500 °C for 2 h to obtain the single crystalline phase. The phase formation, crystallinity, and surface topography of synthesized ZnCr2O4 NRs were explored by X-ray diffraction (XRD), UV-Vis reflectance spectroscopy (UVDRS), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, and vibrating sample magnetometry (VSM). XRD analysis confirms the formation of spinel ZnCr2O4 NRs. The FTIR spectrum displays the two vibrational peaks of Cr–O, and Zn–O at 489 and 615 cm–1, correspondingly. These vibrational bonds were correlated with ZnCr2O4 and revealed the production of cubic spinel ZnCr2O4 NRs. FESEM indicates the presence of hexagonal-rod-shaped particles. EDX spectrum demonstrates the elemental composition of the ZnCr2O4 NRs and confirms the primary peak of Zn, Cr, and O. The obtained ZnCr2O4 NRs exhibit an antiferromagnetic behavior. The bandgap energy of ZnCr2O4 NRs was ascertained and was shown to be 3.45 eV. Furthermore, the antifungal and antibacterial effect of ZnCr2O4 NRs was examined against pathogenic strains by disc diffusion technique. Besides these, the antimalarial activity of ZnCr2O4 NRs was studied against Plasmodium falciparum. Thus, the as-synthesized ZnCr2O4 NRs showed significant antibacterial, antifungal and antimalarial activity and may be helpful for research opening a novel horizon in nanomedicine. Highlights: Spinel ZnCr2O4 nanorods (NRs) successfully synthesized via sol-gel auto combustion approach. UV-Vis-DRS, XRD, FESEM, EDX, HRTEM-SAED, VSM, and FTIR analyses were performed. FESEM and HRTEM analysis revealed the hexagonal-shaped morphology for ZnCr2O4 NRs. The ZnCr2O4 NRs exhibited excellent antibacterial, antifungal, and antimalarial activity. [ABSTRACT FROM AUTHOR]

Determination of various chemical nutrients present within food samples using green nano-modified carbon paste working electrode (GNM-CPWE) is a novel and cost-effective technique. In addition, wastewater treatment in the presence of high surface area green nanocatalysts attracts researchers worldwide. In the present study, zinc oxide nanoparticles (ZnO NPs) were synthesized by using Acanthus sennii leaf extract within three volume ratios as 2:3 (40 mL precursor: 60 mL extract), 1:1 (50 mL precursor: 50 mL extract), and 3:2 (60 mL precursor: 40 mL extract). Physicochemical characterization of ZnO NPs was confirmed using modern technical tools such as XRD, SEM–EDX, TEM, HR-TEM, SAED, UV-DRS, and FTIR methods. Comparative performance studies of ZnO NPs form within different volume ratios were investigated in sensing of ascorbic acid (AA) and degradation of acid orange 88 (AO88) dye. The average crystallite size was found to be 24.19, 19.55, and 23.07 nm for the 2:3, 1:1, and 3:2 ratios, respectively. SEM–EDX with TEM and HR-TEM-SAED depicts that ZnO NPs have spherical shape. UV-DRS proved that the 2:3, 1:1, and 3:2 have bandgap (Eg) energy of 3.28, 3.31, and 3.25 eV, respectively. FTIR analysis indicates the presence of various capping and reducing agents within leaf extract of Acanthus sennii. Electrochemical sensing potential of ZnO (1:1) modified CPWE toward AA was found to be more effective with a best detection limit of 0.200 mM as compared to the counterpart ratios. This might be due to its small D and enhanced catalytic property. The percent degradation efficiency of ZnO (1:1) toward AO88 dye was calculated to be 62.6%. The enhanced degradation potential of ZnO (1:1) might be attributed due to its optical property and relatively small D value as compared to the counterpart ratios. [ABSTRACT FROM AUTHOR]

The application of zinc oxide-based nanocomposite is one of the novel approaches utilized for the development of electronic devices. The sol-gel and auto combustion procedures were employed to synthesize porous PVA aided ZnO/Fe2O3 nanocomposite (PBNC). The n-type iron (III) oxide was successfully coupled with n-type ZnO. The characterizations conducted to explore the significant changes in the physical properties of as-synthesized materials revealed that the surface area, porosity, and charge transfer capability improvement on the PBNC, compared to ZnO. Using the DTG analysis, 500 °C was confirmed to be the optimal calcination temperature to degrade the PVA polymer after acting as a capping agent and impurities that have a boiling point of less than 500 °C. The XRD pattern and TEM image analysis validated the nanometer range size of the materials (10–70 nm). The SEM image and BET spectral analyses confirmed the porous nature of the PBNC, supporting results obtained from the HRTEM (IFFT) and SAED pattern analysis. The EDXS, XPS, and HRTEM analyses were appliedapplied for Zn, Fe, and O elemental composition and certainty of ZnO. The presence of improved charge transfer property for PBNC, compared to ZnO, has been evidenced by CV and EIS studies. The PBNC also showed enhanced ascorbic acid detection capability compared to ZnO. [ABSTRACT FROM AUTHOR]

Ethiopian medicinal plant, Vernonia amygdalina Del. mediated green silver nanostructures (V-SNS) were successfully synthesized for the first time. The surface amalgamation of biomolecules of plant leaf extract around Ag nanostructures has also been approved by the most advanced techniques which were employed to characterize the NSs. The presence of absorbance maxima, λmax at 454 nm confirms the formation of V-SNS. UV-DRS studies revealed the band gap of 2.09 eV for NSs. The role of biomolecules as capping agents for V-SNS was authenticated by FT-IR spectra. The presence of four sharp peaks in the XRD pattern of NSs confirmed the highly crystalline nature of NSs. The TGA-DTA studies revealed that Ag NS is thermally stable above 570 °C. The purity of the NSs was corroborated by SEM-EDAX analysis. The average particle size of V-SNS was deduced to be 35.24 nm. In addition, TEM micrographs revealed the presence of V-SNS with varieties of nano-sized shapes. TEM-HRTEM-SAED analysis authenticated the presence of silver NS with interplanar spacing values of 0.248 nm and 0.243 nm which conformed to Ag (111) lattice fringes of silver. The V-SNS showed significant synergistic antibacterial influence versus S. aureus, E. coli, P. aeruginosa, and E. aerogenes. The uppermost zone of inhibition of 18 mm was inscribed against P. aeruginosa bacteria. The better electrochemical properties of V-SNS electrode as revealed by cyclic voltammograms, Nyquist and Bode plots make it suitable for potential electrochemical sensor application. V-SNS exhibited better photocatalytic activities against Acid orange 8 and Acid red 88 dyes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This work reveals a green combustion route for the synthesis of TiO2, Fe2O3 and TiO2-Fe2O3 nanocomposites as photocatalysts for decolorization of Titan Yellow (TY) and Methyl Orange (MO) dyes at room temperature in aqueous solution concentration of 20 ppm under UV-light irradiation. We observed that the TiO2-Fe2O3 nanocomposite shows superior photocatalytic activity for TY dye compared to pure TiO2 and Fe2O3. Rate constant (k) values of TiO2, Fe2O3 and TiO2–Fe2O3 for TY and MO are 0.0194, 0.0159, 0.04396 and 0.00931, 0.00772 0.0119 kmin−1 respectively. The surface area and pore volume of TiO2-Fe2O3 nanocomposite were found to be 71.56 m2/g and 0.076 cm3/g, respectively as revealed by BET studies. From the Barrett–Joyner–Halenda (BJH) plot, the mean pore diameter of TiO2-Fe2O3 nanoparticles was found to be 2.43 nm. Further, the TiO2-Fe2O3 nanocomposite showed good electrochemical behavior as an electrode material for supercapacitors when compared to pure TiO2 and Fe2O3 nanoparticles resulted in stable electrochemical performance with nearly 100% coulombic efficiency at a scan rate of 10 mV/s for 1000 cycles. Interestingly, the novelty of this work is that the designed supercapacitors showed stable electrochemical performance even at 1000th cycle, which might be useful for rechargeable supercapacitor applications. The electrochemical properties of the nanocomposites were compared by the data obtained by cyclic voltammograms, charge-discharge tests and electrochemical impedance spectroscopic studies. These results demonstrated that the TiO2-Fe2O3 nanocomposite showed stable performance compared to TiO2 and Fe2O3 nanoparticles at current density of 5 Ag−1. [ABSTRACT FROM AUTHOR]