Phyto-Mediated Synthesis of Pure and Silver-Doped Zinc Oxide Nanoparticles Using <i>Stachytarpheta Jamaicensis</i> Leaf Extract: Optical, Morphological and Antibacterial Properties

Novel polyvinyl pyrrolidone capped pure, Ag (1-3%) and Cu doped (1-3%) zinc oxide (ZnO) nanoparticles (NPs) were successfully synthesized via the co-precipitation method. The synthesized NPs were characterized by UV-visible spectrophotometry, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and field emission scanning electron microscopy (FE-SEM). Compared to pure ZnO, the absorption bands of Ag and Cu doped ZnO NPs were shifted and, further, the band gap energy was also decreased which confirms the incorporation of Ag and Cu into the ZnO lattice. The XRD diffraction peak confirms that all the synthesized compounds are found to be of highly crystalline hexagonal wurtzite structure. In addition, the presence of Ag and Cu in the ZnO NPs was further evidenced from EDS analysis. FE-SEM images established the morphology of the doped ZnO NPs which was not affected by the addition of Ag and Cu. The photocatalytic activity of undoped, Ag doped (1-3%) and Cu doped (1-3%) ZnO NPs were tested with brilliant green dye under UV irradiation. Degradation study reveals that doping has a distinct effect on the photocatalytic behavior of ZnO NPs. In addition to that, kinetic, thermodynamic and reusability studies have been performed for the 2% Ag doped ZnO NPs.

Comparison of the photocatalytic degradation of trypan blue by undoped and silver-doped zinc oxide nanoparticles

The sol–gel technique was used in the chemical synthesis and characterizations based on structural, morphological, optical and electrical studies of pure and Ag-doped zinc oxide (ZnO) nanoparticles. X-ray diffraction, scanning electron microscopy, energy Dispersive X-ray spectrometry, transmission electron microscope, ultraviolet spectroscopy, photoluminescence and FT-IR analysis were used to perform the characterization of the morphological analysis, optical studies, phase purity and crystalline size. The Powder X-ray diffraction results proved polycrystalline nature of ZnO with a hexagonal wurtzite structure. Debye-Scherrer’s formula was used to evaluate the average crystallite size of pure and Ag-doped ZnO. Their values have been determined to be 14 and 18 nm respectively. To examine the various functional groups FTIR was utilized. The unique aggregation of the particles was stated by the scanning electron microscopy investigation and transmission electron microscope analysis was used to substantiate the nanosphere formation. Here, the estimated optical band gap value for pure and Ag-doped ZnO nanoparticles was 3.22 and 3.17 eV, respectively. UV–visible spectroscopy was used to perform this process. Photoluminescence studies have proved the Ag-doped ZnO sample of the blue shift emission bands. At different frequencies and temperatures, under specific conditions, the dielectric properties like dielectric constant, dielectric loss and AC conductivity of Ag-doped ZnO nanoparticles were analyzed.

Zinc oxide (ZnO) and silver doped zinc oxide (Ag-ZnO) nanoparticles were prepared using zinc nitrates as oxidizers, glycine and citric acid as fuels as solution combustion synthesis (SCS) at 500°C. X-ray diffraction (XRD) pattern demonstrates the presence of Ag+ in the hexagonal zincite structure of ZnO. The average crystalline size of the particles of ZnO and Ag-ZnO were found to 47 nm and 74 nm respectively. From the Fourier transform infrared (FTIR) spectrum, the composition of Ag doped ZnO confirmed Ag-Zn-O stretching vibration at 510 cm-1. The UV-Visible absorption spectra results showed that synthesized ZnO and Ag-ZnO nanoparticles exhibited UV-visible absorption peaks at 370 nm, corresponds to a band gap of 3.24 eVand 3.08 eV respectively. Based on the above characterization techniques, the incorporation of silver affects the structural and optical behaviour of ZnO nanoparticles. The ZnO nanoparticles were observed that the particles are spherical morphologies. EDAX spectrum indicates no other elemental presence in the synthesized nanoparticle. The present work illustrate the Ag-ZnO nanoparticles as a photo-catalyst to decompose contaminants in the presence of UV light. The photo-catalytic activity of ZnO samples were investigated by UV- irradiation of methylene blue solution in a photocatalytic setup. The resulting mixtures were irradiated with UV light for a period of 45 mins. Based on results, the photocatalytic activity of Ag-ZnO nanoparticles were enhanced by the addition of Ag in pure ZnO nanoparticles. Ag doped ZnO nanoparticles showed higher photocatalytic activity efficiency than pure ZnO nanoparticles.

Herein, we prepared the zinc oxide (ZnO) and silver doped zinc oxide (Ag-ZnO) nanoparticles (NPs) using Berberis aristata plant extract as a reducing, capping and stabilizing agent. The x-ray diffraction (XRD) pattern confirms the formation of pure hexagonal wurtzite structure for both the samples with P4mm space group. The crystallite size reduces from 21.313 nm to 18.179 nm with the Scherrer technique with doping of Ag ions on ZnO NPs, while the Williamson Hall (WH) approach likewise demonstrates a decrease in crystallite size from 26.602 nm to 21.522 nm. The lattice strain increases from 0.0031 to 0.0064, indicating the presence of Ag-ions in the crystal lattice of ZnO NPs. For both samples, the metal-oxygen bond formation is supported by the Fourier Transform Infrared (FTIR) spectra. For ZnO, the peak in the UV-visible spectrum is approximately around 365 nm, but for Ag-ZnO, two peaks are observed around 235 nm and 360 nm. With the Ag doping, the bandgap increases from 3.01 eV to 3.02 eV. Transmission Electron Microscopy (TEM) micrographs show the formation of crystalline particles and Field Emission Scanning Electron Microscopy (FESEM) pictures show the formation of aggregated NPs with a spherical shape. Energy Dispersive x-ray Spectroscopy (EDX) and x-ray Photoelectron Spectroscopy (XPS) demonstrate the chemical purity of both the samples. The antibacterial activity of ZnO NPs was highest against Staphylococcus aureus i.e., 15 ± 0.53 mm, whereas, for Ag-ZnO NPs the highest activity was against Salmonella typhi i.e., 19 ± 0.53 mm.

Biosynthesis of Al-doped ZnO nanoparticles with different Al doping ratio for methylene orange dye degradation activity

Nowadays, the current synthesis techniques used in industrial production of nanoparticles have been generally regarded as nonenvironmentally friendly. Consequently, the biosynthesis approach has been proposed as an alternative to reduce the usage of hazardous chemical compounds and harsh reaction conditions in the production of nanoparticles. In this work, pure, iron (Fe)-doped and silver (Ag)-doped zinc oxide (ZnO) nanoparticles were successfully synthesized through the green route using Clitoria ternatea Linn. The optical, chemical, and physical properties of the biosynthesized ZnO nanoparticles were then analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), UV-Vis diffuse reflectance spectroscopy (DRS), zeta potential measurement, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and surface analysis. The biosynthesized ZnO nanoparticles were crystallized with a hexagonal wurtzite structure and possessed smaller particle sizes than those of commercially or chemically produced samples. The existence of biomolecules to act as reducing and stabilizing agents from C. ternatea Linn aqueous extract was confirmed using FTIR analysis. The biosynthesized ZnO nanoparticles mainly comprised of negatively charged groups and responsible for moderately stable dispersion of the nanoparticles. All these properties were favorable for the sonocatalytic degradation of Congo red. Sonocatalytic activity of ZnO nanoparticles was studied through the degradation of 10 mg/L Congo red using ultrasonic irradiation at 45 kHz and 80 W. The results showed that the sonocatalytic degradation efficiency of Congo red in the presence of biosynthesized ZnO nanoparticles prepared at 50 °C for 1 h could achieve 88.76% after 1 h. The sonocatalytic degradation efficiency of Congo red in the presence of Ag-doped ZnO was accelerated to 94.42% after 10 min which might be related to the smallest band gap energy (3.02 eV) and the highest specific surface area (10.31 m2/g) as well as pore volume (0.0781 cm3/g). Lastly, the biosynthesized ZnO nanoparticles especially Ag-doped ZnO offered significant antibacterial potential against Escherichia coli which indicated its ability to inhibit the normal growth and replication of bacterial cells. These results affirmed that the biosynthesized ZnO nanoparticles could be used as an alternative to the current chemical compounds and showed a superior sonocatalytic activity toward degradation of Congo red.

This study was designed to synthesise zinc oxide (ZnO) and silver-doped zinc oxide (ZnO:Ag) nanoparticles using an aqueous extract of melon peels as a natural reducing and stabilising agent. For the first time, melon peel extract was used to produce both pure ZnO and Ag-doped ZnO nanoparticles at doping levels of 2% and 3%. The synthesised nanoparticles were characterised by FTIR, XRD, SEM, and EDX methods. XRD analysis revealed a hexagonal crystal structure in all samples, with crystallite sizes of 28.51 nm (ZnO), 26.06 nm (ZnO:Ag 2%), and 37.96 nm (ZnO:Ag 3%). FTIR results confirmed the incorporation of silver into the ZnO matrix. Scanning electron microscopy (SEM) showed mostly spherical particles, with ZnO:Ag 2% exhibiting welldefined crystallinity. EDX results confirmed the successful doping of ZnO with silver. The synthesis of ZnO:Ag 2% nanoparticles demonstrated significant antibacterial properties against Staphylococcus aureus, Bacillus cereus, and Escherichia coli, with photocatalysis revealing 85% degradation of methylene blue (MB).

Nanotechnology is a rapidly developing field of research that studies materials having dimensions of less than 100 nanometers. It is applicable in many areas of life sciences and medicine including skin care and personal hygiene, as these materials are the essential components of various cosmetics and sunscreens. The aim of the present study was to synthesize Zinc oxide (ZnO) and Titanium dioxide (TiO2) nanoparticles (NPs) by using Calotropis procera (C. procera) leaf extract. Green synthesized NPs were characterized by UV spectroscopy, Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM) to investigate their structure, size, and physical properties. The antibacterial and synergistic effects of ZnO and TiO2 NPs along with antibiotics were also observed against bacterial isolates. The antioxidant activity of synthesized NPs was analyzed by their α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity. In vivo toxic effects of the synthesized NPs were evaluated in albino mice at different doses (100, 200, and 300 mg/kg body weight) of ZnO and TiO2 NPs administered orally for 7, 14, and 21 days. The antibacterial results showed that the zone of inhibition (ZOI) was increased in a concentration-dependent manner. Among the bacterial strains, Staphylococcus aureus showed the highest ZOI, i.e., 17 and 14 mm against ZnO and TiO2 NPs, respectively, while Escherichia coli showed the lowest ZOI, i.e., 12 and 10 mm, respectively. Therefore, ZnO NPs are potent antibacterial agents compared to TiO2 NPs. Both NPs showed synergistic effects with antibiotics (ciprofloxacin and imipenem). Moreover, the DPPH activity showed that ZnO and TiO2 NPs have significantly (p > 0.05) higher antioxidant activity, i.e., 53% and 58.7%, respectively, which indicated that TiO2 has good antioxidant potential compared to ZnO NPs. However, the histological changes after exposure to different doses of ZnO and TiO2 NPs showed toxicity-related changes in the structure of the kidney compared to the control group. The current study provided valuable information about the antibacterial, antioxidant, and toxicity impacts of green synthesized ZnO and TiO2 NPs, which can be influential in the further study of their eco-toxicological effects.

Tuning the structural, morphological, optical, wetting properties and anti-fungal activity of ZnO nanoparticles by C doping

The present study investigates the effect of Silver doped zinc oxide (Ag-ZnO) and Zinc Oxide (ZnO) nanoparticles fuel additives on the performance and emission characteristics of diesel engine. The ZnO and Ag-doped ZnO nanoparticles (NPs) prepared by the hydrothermal method. After the preparation, the XRD pattern of ZnO and Ag-doped ZnO NPs revealed hexagonal wurtzite structure and calculated their crystallite size was 19 and 37 nm. FTIR spectra confirmed the presence of Ag and Zn-O vibration modes. The micrograph (or nano) of scanning electron microscopy and transmission electron microscopy shows the spherical shape with less agglomerated ZnO and Ag-doped ZnO NPs. Both ZnO and Ag-doped ZnO NPs were added in Pongamia B20 biodiesel blends with the various proportions as an additive. Furthermore, the experimentally measured results exhibited significant emission (CO, NOx) properties of biodiesel blends with the addition of ZnO and Ag-ZnO NPs in diesel engines.

This research presents a green synthesis of high-quality graphene (G), zinc oxide (ZnO) and graphene/zinc oxide (G/ZnO) nanocomposites. Zinc Oxide nanoparticles (ZnO NPs) were synthesised using Amarus Pinnantum extracts, while graphene was derived from Bryophyllum Pinnatum shoot plant extracts. The integration of graphene into the ZnO matrix was investigated to enhance its structural, optical, and electrical properties, particularly electron mobility. The synthesised materials were characterised using UV-Vis spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS). UV-Vis spectra revealed characteristic absorption bands for graphene, ZnO, and G/ZnO. FTIR analysis confirmed the presence of functional groups associated with each material, including 593 cm-1 (Zn-O bending vibrations), 1088 and 1459 cm-1 (C-H Alkyl group bending vibrations), 1583 cm-1 (C=C Aromatic stretching vibration), and 3467 and 3777 cm-1 (O-H Hydroxyl group stretching vibration) in the G/ZnO nanocomposites. Scanning Electron Microscopy (SEM) images showed spherical zinc oxide (ZnO) nanoparticles, a rough, flake-like graphene structure, and a porous, aggregated morphology for the G/ZnO nanocomposite. EDS analysis verified the elemental composition of the materials. The electrical properties of the G/ZnO nanocomposite were significantly improved compared to pure graphene and ZnO nanoparticles. The composite exhibited a higher current (4.62 μA) and lower resistivity (405.56 Ω·m) at a specific voltage (0.60 V). This enhancement is attributed to the formation of a percolative network within the composite, which facilitates efficient charge transfer and improves electron mobility. These findings suggest that the G/ZnO nanocomposite holds promise for applications in optoelectronic devices.

Objective: To study the structural, optical and conductivity properties of ZnO nanoparticles synthesized by two different methods such as hydrothermal and sol-gel methods. Methods/Analysis: ZnO is synthesized at various temperatures 100oC, 150oC and 200oC using hydrothermal method with oxalic acid and zinc acetate and using sol-gel method with sodium hydroxide, zinc chloride and zinc nitrate. Findings: For both methods, the average crystal size determined by X-ray Diffraction (XRD) is noted to be in the range 20–30 nm. The pattern confirmed the composition, crystallinity and the synthesized products are ZnO with high purity and the hexagonal phase. The absorption peak of ZnO nanoparticles has a blue-shift compared with that of the bulk. In hydrothermal method, the band gap is large (i.e) from 4.4–4.9 eV and in the sol-gel method 3.5–3.9 eV. ZnO nanoparticles synthesized by both methods exhibit similar luminescence. Scanning Electron Microscopy (SEM) pictures reveal the morphology as near-spherical prismatic nano particles for hydrothermal method and as nanoflakes for sol-gel method. The Energy Dispersive X-ray Spectroscopy (EDAX) analysis confirms the presence of ZnO only and no other element. The conductivity decreases with the growth temperature as well as the concentration of the ZnO samples by sol-gel method. In contrast, the conductivity of the sample prepared by hydrothermal method, increases with the growth temperature but decreases with the concentration. Novelty: In addition, conductivity of the synthesized ZnO nanoparticles is measured for various concentrations of ZnO. The results of both the methods are compared with each other and with those reported in the literature.

Zinc oxide (ZnO) nanoparticles are widely used in cosmetics, coatings, and industrial formulations due to their UV-absorbing and antimicrobial properties; however, their increasing release into aquatic systems has raised concerns about potential ecological risks. This study evaluates the acute toxicity of pure and silver-doped ZnO (Ag-ZnO) nanoparticles using Artemia salina as a marine model organism. Nanoparticles were synthesized via a reflux-assisted method and characterized by UV–Vis spectroscopy, HRTEM, ED, FTIR, and EDX analyses, confirming a crystalline wurtzite structure, particle sizes of 10–30 nm, and successful incorporation of 5% Ag. Silver doping produced a slight blue shift in the absorption edge and minor lattice distortions, indicating modifications in the electronic structure. Toxicity assays revealed clear concentration- and time-dependent decreases in nauplii survival. Dose–response modeling showed LC50 values of 358 ppm (24 h) and 64 ppm (48 h) for pure ZnO, whereas Ag-ZnO exhibited LC50 values of 607 ppm (24 h) and 28 ppm (48 h). These results indicate that Ag doping does not enhance short-term toxicity but markedly increases toxicity after prolonged exposure. Overall, the findings highlight the need to consider both nanomaterial composition and exposure duration in ecotoxicological assessments and provide relevant data for evaluating the environmental impact of doped nanomaterials in marine systems.

This chapter focuses on zinc oxide (ZnO) nanoparticle (NP) synthesis using the co-precipitation method with the aqueous plant extract of Rubus fairholmianus. The synthesized NP was characterized by different techniques using ultraviolet-visible (UV-Vis) and Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The SEM results revealed that the ZnO NPs formed a spherical structure and accumulated in the form of flower-shaped bundles. The energy dispersive X-ray analysis (EDAX) report exhibited that the ZnO NPs contain weight percentages of 34.13% zinc and 65.87% oxygen. The ZnO NPs reported a total phenolic, tannin and flavonoid content of 412.82 ± 9.27 mg GAE/g, 99.38 ± 7.77 mg RE/g, and 25.06 ± 1.71 mg GAE/g, respectively. The ZnO NPs showed better antioxidant and anti-inflammatory activities. The erythrocyte membrane against hypotonic-induced lysis of 80.17% compared to the diclofenac standard. Hence the ZnO NPs of R. fairholmianus possess better pharmacological activities that could be used to develop potential drugs against chronic diseases.