Narrow Results

Cu/CuO nanoparticles (NPs) have received extensive attention owing to their tremendous antifungal and antibacterial properties. Cu/CuO NPs are used in diverse fields, viz. electronics, catalysis, photonics, biosensing, optoelectronics and many more. Herein, we described the green synthesis of Cu/CuO NPs using Cuscuta reflexa (Amarvel) plant material at room temperature. The prepared NPs were characterized by routine technique, viz. XRD, UV-Vis, SEM and TEM. The typical size found was merely 7–10nm using the TEM technique. The as-prepared solution of NPs was tested against the Diptera larval nymph of mosquitoes. These mosquitoes breed in monsoon (rainy season) in stagnant water. It is observed that NPs were very effective against these larvae, which were killed overnight when just four drops of the as-prepared NPs solution were directly added to a 10ml water sample containing mosquito larvae. Overall, the biosynthesized Cu/CuO NPs showed good insecticidal activity against the parasitic disease malaria-causing Anopheles mosquitoes in the larval stage itself. We believe the outcome will lead to a new era in the preparation of innovative organic insecticides.

Herein, we report the biosynthesis of Ni/NiO nanocrystals (NCs) using cuscuta reflexa (Amarvel) plant material. The formation of nickel (Ni) NCs was confirmed through numerous procedures viz. X-ray diffraction (XRD), UV-Vis., SEM-EDX and TEM. The prepared Ni/NiO nanoparticles were regular/irregular cube shape with average cube length of 150–200nm calculated using the TEM technique. Fourier transform infrared spectroscopy (FTIR) spectroscopy analysis showed the presence of chemicals from cuscuta reflexa extract. The synthesized Ni/NiO NCs solution was tested against storage grain pests as well as against mosquito larvae. It was observed that NPs were very effective against the storage grain pests (wheat weevil and red flour beetles). The effect of concentrations/dose was also studied along with varied times of action for the larvicidal effect of the as-prepared Ni/NiO NCs solution. The positive results from this study will certainly open new doors for the development of nanoNi-based green pesticides.

In order to reduce the enormous costs of photocatalytic processes, the development of new photocatalysts sensitive to visible light constitutes a promising strategy to boost the efficiency of this method in water treatment. In this paper, strontium cobaltite nanoparticles (SrCo₂O₄ NPs) were shaped by simple, ecological and economical methods using cobalt and strontium nitrates as precursor and freshly isolated chicken egg white as capping agents. The crystalline product SrCo₂O₄ NPs was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Ultraviolet–Visible (UV–Vis) spectroscopy studies. The SrCo₂O₄-catalyzed Congo red (CR) degradation under visible light is investigated. XRD analysis showed that the sample was indeed crystallized in the cubic spinel structure (space group Fd3m). The average size of the nanoparticles was estimated to be ∼28nm. The FT-IR spectrum shows two bands at 620 and 573${\text{cm}}^{-1}$, which are characteristic of the spinel strontium cobaltite crystalline structure. The two optical band gap energy of synthesized photocatalyst estimated from UV–Visible spectrum is 2.07 and 3.48eV. The developed photocatalyst exhibits significant photocatalytic degradation of RC in an acidic medium with 97% of the dye mineralized after 5h.

This study aimed to synthesize, physicochemical characterize, and evaluate the biomedical properties of silver nanoparticles (AgNPs). The methodology section included using two green methods to synthesize silver nanoparticles and comparing them to be chosen appropriately by future researchers. Two samples were obtained: one from green microwave-assisted (MSGS) called AgNPs-1 and the second sample prepared by rapid synthesis method called AgNPs-2; these samples were characterized for their physicochemical using X-ray Powder Diffraction (XRD), Dynamic Light Scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDX). Moreover, the biomedical properties were evaluated by determining the antibacterial and cytotoxicity studies. The results observed two peaks in the UV–Vis spectroscopy were indicated at 446nm and 454nm for AgNPs-2 and AgNPs-1, respectively, which first revealed the different particle sizes and conformed in the XRD. DLS showed that the particle sizes of AgNPs-2 were 84.30nm and 121nm, respectively, while AgNPs-1 were 120.20nm and 437nm, respectively. The morphology of the synthesized samples was investigated using scanning electron microscopy (SEM) and showed different shapes, which were spherical and spherical-rod for AgNPs-2 and AgNPs-1, respectively. The presence of the silver element was indicated at 3KeV in EDX for both samples. The antibacterial test showed a significant ability to inhibit the growth of the four evaluated bacteria, and AgNPs-2 showed more effect than AgNPs-1 because of the size of the particles. The cytotoxicity study showed no toxic effect, and the average cell availability of HeLa cells was 91%. The current research demonstrated that new products from natural materials have good antibacterial properties that can be used as antibiotics with nontoxic effects in the biomedical field.

The (Ni/NiO)${}_{CG}$/g-C₃N₄ nanocomposite was green synthesized using Cleome gynandra via sol–gel method. The photocatalytic dye decomposition, antioxidant and antidiabetic activities of the nanocomposite were studied and compared with those of (Ni/NiO)${}_{\mathrm{\text{CG}}}$ and g-C₃N₄. The nanocomposite exhibited enhanced photocatalytic efficiency of 97% compared to (Ni/NiO)${}_{\mathrm{\text{CG}}}$ (63%) and g-C₃N₄ (80%) due to the synergistic effect between both the composite partners. The nanocomposite, (Ni/NiO)${}_{\mathrm{\text{CG}}}$/g-C₃N₄ showed notable antioxidant activity in DPPH (IC${}_{50}$ of $41.76\pm 0.88$$\mu$g/mL with 87.06% of inhibition at 500$\mu$g/mL) and ABTS (IC${}_{50}$ of $47.60\pm 0.81$$\mu$g/mL with 88.40 % of inhibition at 500$\mu$g/mL) radical scavenging assays. The green synthesized nanocomposite also exhibited significant antidiabetic activity in $\alpha$-amylase and $\alpha$-glucosidase enzyme inhibition assays with the IC${}_{50}$ of $33.83\pm 0.53$$\mu$g/mL and $49.94\pm 0.64$$\mu$g/mL, respectively. The XRD and SEM analyses confirmed the nanocomposite formation of (Ni/NiO)${}_{CG}$/g-C₃N₄. The results showed that the green synthesized (Ni/NiO)${}_{\mathrm{\text{CG}}}$/g-C₃N₄ has desirable dye degradation, antidiabetic and antioxidant properties. This paper presents the results of the remarkable photocatalytic dye decomposition, antidiabetic and antioxidant properties of the nanocomposite (Ni/NiO)${}_{\mathrm{\text{CG}}}$/g-C₃N₄ synthesized via an eco-friendly greeny way using Cleome gynandra leaf extract which may be the first report of this kind utilizing this plant.

This study intended to synthesize Nickel-doped Cerium oxide (Ni-CeO₂ NPs) nanoparticles using Pedalium Murex leaf extract. X-ray diffraction (XRD) was used to investigate the structure of the Ni-CeO₂ NPs. The XRD measurements showed that the Ni-CeO₂ NPs crystallized into the face-centered cubic system. The Ni(1%)-CeO₂ and Ni(3%)-CeO₂ NP’s crystallite sizes were between 47nm and 59nm. FTIR and Raman spectral studies were conducted to investigate the sample’s atomic vibrations and chemical bonding. Energy-dispersive X-ray study and field-emission scanning electron microscopy were performed to examine the surface texture and chemical assembly of the Ni-CeO₂ NPs. UV–Vis DRS spectrum study was performed to ascertain the reflectance characteristics and bandgap of Ni-CeO₂ NPs. The Ni(1%)-CeO₂ and Ni(3%)-CeO₂ NPs were found to have bandgaps of 2.73eV and 2.82eV, respectively. Electrochemical impedance spectroscopy and cyclic voltammetry were employed to explore the electrochemical nature of Ni-CeO₂ NPs and their capacitive properties at various scanning rates. Using the agar well-diffusion technique, the antifungal activities of Ni-CeO₂ NPs were assessed. The experimental findings illustrate the utility of Ni-CeO₂ NPs for supercapacitor electrode material and healthcare applications.

The development of nanomaterials using green synthesis methods is gaining attention due to their potential to reduce environmental pollution and health risks associated with traditional chemical synthesis methods. Among the various transition metals, zirconia has gained significant interest as filling materials and implants in dentistry due to its excellent mechanical and chemical properties. In this study, we developed ecofriendly zirconium oxide nanoparticles using Biancaea sappan extract as a capping agent and then functionalized them with Quercetin. Further, their anti-inflammatory property and hemocompatibility were evaluated to target their application as filling materials. The biogenic zirconium oxide nanoparticles (B-ZrO₂NPs) and quercetin functionalized biogenic zirconium oxide nanoparticles (BQZN) were characterized by UV–Vis Spectroscopy (UV–Vis), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy X-ray analysis (EDX). B-ZrO₂NPs showed maximum absorbance at 267nm and 383nm. FTIR showed characteristic stretching at 3381cm${-1}^{}$, confirming the O–H group in the extract and Quercetin used for BQZN formation. The FTIR spectra of BQZN displayed the presence of the characteristic peaks observed in the spectra of B-ZrO₂NPs and Quercetin. The broad XRD pattern confirmed the amorphous nature of the zirconia. SEM revealed the spherical morphology of B-ZrO₂NPs and BQZN with a size range of around 90nm and 120nm, respectively. EDAX of BQZN revealed the presence of 45.7wt.% Zr, 32.9% oxygen and 21.4% of carbon. In vitro bioactivity studies revealed that BQZN exhibited significant anti-inflammatory activity, as evidenced by the inhibition of protein denaturation. The nanoparticles were also demonstrated for their hemocompatibility with erythrocytes. These findings highlight the potential of BQZN as a promising hemocompatible dental filling with significant anti-inflammatory properties. Further in-depth in vivo studies are required to fully understand their efficacy and toxicity.

In this work, the synthesis of nickel oxide (NiO) using nickel acetate through a green synthetic approach has been reported. The green synthesis approach was employed for the synthesis of NiO nanoparticles as it employs plant-based precursors and mild reaction conditions, reducing environmental impact and avoiding the use of hazardous chemicals while maintaining high efficiency and scalability. The structural, spectral and morphological properties of the synthesized NiO nanoparticles were characterized using Powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Further, Electrochemical Impedance Spectroscopy (EIS) studies like cyclic voltammetry and Nyquist plots were utilized for electrochemical studies. The energy storage behavior of the synthesized NiO nanoparticles was studied by Galvanostatic Charge-Discharge (GCD) curves. Finally, the NiO nanoparticles were subjected to photocatalytic activity on exposure to UV light. The nanoparticles exhibited a cubic phase with crystallite sizes matching well between XRD and TEM results. Electrochemical studies demonstrated excellent cycling stability, with more than 90% of the initial capacitance retained even after 2000 charge–discharge cycles. Photocatalytic activity of the NiO nanoparticles achieved a degradation efficiency of 71.62% for Fast Blue dye under UV light exposure for 120 min, indicating their significant potential for environmental applications. Additionally, the energy bandgap of the NiO nanoparticles was determined to be 3.57eV.

The advancement of heteroatom-doped photocatalysts represents a promising approach to enhancing the efficiency of photocatalytic hydrogen production. Nonetheless, current doping methods often use toxic and complex processes, along with environmentally harmful materials. For example, traditional sodium dihydrogen phosphate dopants emit toxic fumes at high temperatures. Thus, there is an urgent need to investigate sustainable and direct doping techniques. This study presents the synthesis of phosphorus-doped graphite carbon nitride (P-g-C₃N${}_4)$ through a solvent pre-mixing assisted calcination process, utilizing nontoxic ammonium dihydrogen phosphate as the dopant, the optimal photocatalytic performance was observed at a phosphorus doping concentration of 5wt.%, resulting in a hydrogen production rate of 268$\mu$mol/g/h. Notably, the foaming effect resulting from the thermal decomposition of ammonium dihydrogen phosphate significantly enhances the specific surface area of P-g-C₃N₄, and exhibits superior light absorption capabilities and enhanced photocatalytic activity. The catalyst prepared in this research is both cost-effective and environmentally sustainable, positioning it as a promising candidate for applications in photocatalytic hydrogen production. It provides a new method for the development of clean energy and the solution of environmental pollution problems.

Lead-free sodium niobate (NaNbO₃, NN) and potassium niobate (KNbO₃, KN) nanopowders were successfully synthesized by a simple and green synthesis process in gelatin media. Gelatin, which is a biopolymer, was used as stabilizer. In order to determine the lowest calcination temperature needed to obtain pure NN and KN nanopowders, the produced gels were analyzed by thermogravometric analyzer (TGA). The produced gels were calcined at 500${}^{\circ }$C and 600${}^{\circ }$C. The structural and optical properties of the prepared powders were examined using X-ray diffraction (XRD) technique, transmission electron microscopy (TEM), and UV–Vis spectroscopy. The XRD results revealed that pure phase NN and KN nanopowders were formed at low temperature calcination of 500${}^{\circ }$C and 600${}^{\circ }$C, respectively. The Scherrer formula and size-strain plot (SSP) method were employed to estimate crystallite size and lattice strain of the samples. The TEM images show that the NN and KN samples calcined at 600${}^{\circ }$C have cubic shape with an average particle size of 60.95 and 39.29 nm, respectively. The optical bandgap energy of the samples was calculated using UV–Vis diffused reflectance spectra of the samples and Kubelka–Munck relation.

In this paper, we report the development of a new green, eco-friendly pathway for the synthesis of reduced graphene oxide (RGO). In a typical experiment, graphene oxide (GO) was prepared by the oxidation of graphite powder using Hummer’s method. Prepared GO was then subjected to reduction by using extract of Tagetes erecta (Marigold flower). The samples were characterized by various techniques such as X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) spectroscopy and Raman spectroscopy. RGO synthesized in this work is being probed for diverse applications including biomedical applications.

Surface modification by using citric acid (CA) in the graphene is a process to modify the physicochemical properties of graphene oxide. The strategy that has been proposed depends upon the electrochemical exfoliation of reduced graphene oxide (rGO), and simultaneously, the surface modification of rGO with CA carried out in accordance with the green technique. The synthesis of graphene oxide that has been doped with CA was accomplished via an electrochemical process in an aqueous medium containing fresh lime juice and sulphuric acid (electrolyte heating aided method at $60^{\circ }$C) as an electrolyte. The electrolyte has been prepared using CA & H₂SO₄ (sulphuric acid), and both were mixed in a proportion of 1:2. In order to dilute the H₂SO₄ and perform the sonication, the water that has been pasteurized (according to the USP standards for irrigation) was used. The crystallite size, structural disorder, structure and surface morphology of the CA-doped graphene oxide were identified through X-ray diffraction (XRD) analysis, Raman spectroscopy, Field emission scanning electron microscope (FE-SEM). The presence of oxygen-containing functional group and adsorption has been analyzed using Fourier transform infrared (FTIR), and UV–Vis spectroscopy. The thermal stability of the CA-doped, and without CA-doped thermally reduced graphene oxide (TRGO) has been analyzed via thermogravimetric analysis (TGA). A green, simple, and environmentally friendly method has been demonstrated for the synthesis of CA-doped TRGO by electrochemical synthesis method by using natural dopant.

Yttrium oxide (Y₂O₃) is a promising rare-earth compound that is rarely studied. This study reports on the synthesis, structural, morphological, optical and antimicrobial properties of Y₂O₃ nanoparticles (NPs) synthesized using Agathosma betulina leaf extract. XRD pattern indicated that the crystalline phase was achieved for the sample calcined at $500^{\circ }$C with body-centered cubic symmetry. SEM and TEM images of Y₂O₃ nanopowder showed the nearly spherical morphology of agglomerated NPs with an average diameter of 13nm. Optical properties revealed that the bandgap of Y₂O₃ NPs ($\sim 5.67$eV) has been increased compared with the bulk Y₂O₃ ($\sim 5.5$eV). Moreover, the antimicrobial activity was also evaluated against gram-positive and gram-negative bacteria of clinical interest. Results demonstrated that the synthesized Y₂O₃ NPs exhibited higher bacteriostatic effects against gram-negative bacterial strains due to their thin cell wall structure. These results show that the synthesized Y₂O₃ NPs are suitable for antibacterial control systems and medicines.

As compared to conventional physical and chemical techniques, the biological method (green synthesis) is an economical, nontoxic, fast, eco-friendly and cost-effective technique that utilizes plant extract to generate highly stable and biocompatible nanoparticles. The existing study focuses on the synthesis of zinc sulphide nanoparticles (ZnS NPs) using P. persica leaf extract which is used as a reducing agent and their associated properties. The prepared samples were examined in terms of structural, optical, morphological and compositional properties. The SEM images showed the agglomerated spherical particles while XRD spectra confirmed the hexagonal (wurtzite) phase of synthesized ZnS samples with average crystallite sizes found to vary from 12.45 to 14.36nm. The optical absorption spectra displayed the absorption peaks at 331nm (4.26eV) and 339nm (4.10eV). This blue shift in the absorption band suggests the formation of ZnS NPs compared with bulk ZnS ($\sim 3.68$eV) material. The FTIR peaks from 612– to 630cm${}^{-1}$ and 860– to 1022cm${}^{-1}$ are because of the symmetric bending vibrations of the Zn–S bands. Electrical measurements showed that the resistivity is found to be decreasing with increasing temperature, signifying the semiconducting behavior of the synthesized ZnS NPs. The findings of this study suggest the feasible use of P. persica leaves extract for the production of ZnS NPs which could be utilized as multifunctional material in medical applications, biosensors, photocatalytic and electrical applications.

Nanosized $\alpha$-Al₂O₃ powders were prepared with AlCl${}_3\cdot$6H₂O and NH₄HCO₃ as raw materials by both wet-chemical and mechanochemical methods, through the synthesis of the ammonium aluminum carbonate hydroxide (AACH) precursor followed by calcination. The environmentally benign starch was used as an effective dispersant during the preparation of nanocrystalline $\alpha$-Al₂O₃ powders. X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to characterize the precursor AACH and products. The results show that nanosized spherical $\alpha$-Al₂O₃ powders without hard agglomeration and with particle size in the range of 20–40 nm can be obtained by the two methods. Comparing the two “green” processes, the mechanochemical method has better prospects for commercial production.

In this research, nanocrystalline $\gamma$-${\mathrm{\text{Al}}}_2{\mathrm{\text{O}}}_3$ powders have been synthesized by a novel mechanochemical method, through thermal decomposition of the ammonium aluminum carbonate hydroxide (AACH) precursor. The route involved using low-cost ${\mathrm{\text{AlCl}}}_3\cdot 6{\mathrm{\text{H}}}_2\mathrm{\text{O}}$ and ${\mathrm{\text{NH}}}_4{\mathrm{\text{HCO}}}_3$ as raw materials and environmental-friendly soluble starch as an effective dispersant. The precursor and product were characterized by simultaneous thermogravimetric and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that spherical $\gamma$-${\mathrm{\text{Al}}}_2{\mathrm{\text{O}}}_3$ nanoparticles without hard agglomeration and with particle size in the range of 20–30 nm can be obtained. The crystallite size of products measured from XRD, SEM and TEM were in good agreement. This novel mechanochemical method combined with the use of environmentally benign starch has the advantages of simple operation, low calcination temperature and environmental safety, and will have good prospects for commercial production.

In this paper, we investigate the impact of rice-starch stabilization of gold nanoparticles (AuNPs) on their catalytic and surface-enhanced Raman spectroscopy (SERS) activities. A typical green synthesis protocol was used to prepare AuNPs with rice-starch functioning as the reductant and the stabilizer. The localized surface plasmon resonance (LSPR) of the starch-stabilized AuNPs is pH-sensitive and got red-shifted with the medium’s pH. The average size of the AuNPs formed decreased with the amount of rice-starch up to a certain level. TEM result shows that the polymeric behavior of starch extract may help synthesize the Au nanorod morphologies. AuNPs stabilized by different amounts of rice-starch were applied as the catalysts for the model $p$-nitrophenol reduction reaction. For all AuNP catalysts used, the reaction followed pseudo-first-order kinetics. The catalyst turnover frequencies increased up to a certain level of starch functionalization. Further increase in starch led to a fall in the activity of AuNPs catalyst. The evidence on rate kinetics, induction times, activation energies, and turnover frequencies is combined to explain this phenomenon in terms of starch content. The SERS response of these AuNPs as substrates has also been investigated for methylene blue as the target molecules. AuNP substrates with an excess amount of starch weaken the SERS response and it can be ascribed to decreased light scattering efficiency of NPs as well as reduced interactions of methylene blue molecules with the NP surface.

The present work deals with the investigation of the greener route for the production of silver nanoparticles using Raphanus sativus (R. sativus) bioextract in a continuous flow tubular microreactor. The parameters affecting the particle size and distribution were investigated. From the results obtained it can be inferred that the ascorbic acid (reducing agent) present in the R. sativus bioextract is responsible for the reduction of silver ions. At optimum condition, the particle size distribution of nanoparticles is found between 18nm and 39nm. The absorbance value was found to be decreased with an increase in the diameter of the microreactor. It indicates that a number of nuclei are formed in the micrometer sized (diameter) reactor because of the better solute transfer rate leading to the formation of large number of silver nanoparticles. The study of antibacterial activity of green synthesized silver nanoparticles shows effective inhibitory activity against waterborne pathogens, Shegella and Listeria bacteria.

Nanosized metal aluminates MAl₂O₄, [$\mathrm{\text{M}}=\mathrm{\text{Cu}}$ and Co] are synthesized from their nitrates solution by using pomegranate peel extract as fuel in microwave combustion. MAl₂O₄ [$\mathrm{\text{M}}=\mathrm{\text{Cu}}$ and Co] nanoparticles are grown in microwave assisted synthesis followed by annealing at 700${}^{\circ }$C. The nanoparticles have been characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV-VIS spectroscopy and photoluminescence (PL) spectroscopy. The PXRD analysis has confirmed their spinel composition. The green protocol and microwave combustion route for spinel synthesis are rapid, simple, without any hazardous chemicals as reducing or stabilizing agents and economical.

ZnS nanostructures are synthesized by a wet chemical route using starch as green capping agent under nitrogen environment. The as-prepared nanostructures are characterized structurally, optically and electrically. X-ray diffraction (XRD) spectra confirm that the zinc sulfide (ZnS) nanoparticles have cubic phase (zinc blende). UV–Vis spectrum of the sample clearly shows that the absorption peak exhibits blue shift compared to their bulk counterpart, which confirms the quantum confinement effect of the nanostructures. Its photoluminescence (PL) spectrum shows near band gap emission at 392nm and extrinsic emission at 467nm. The particle sizes calculated from XRD and UV studies are in fair agreement with high resolution transmission electron microscopy (HRTEM) results. Starch is found to be a noble capping agent in bringing quantum confinement. The synthesis under nitrogen environment has been observed to produce quality products by reducing the oxide traces. Moreover, the I–V characteristics under dark and illumination show that ZnS can be more suitable as photodetector.