Search

In the present study, combustion technique is adopted to study the impact of Mg2+ ion doping on ZnAI2O4 nanoparticles (NPs). L-arginine is used as a fuel component. The Mg2+ ions play a pivotal role in persuading various characteristics of ZnAI2O4 NPs. Various characterization technqiues such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), high resolution scanning electron microscopy (HR-SEM), diffuse reflectance spectroscopy (DRS), Thermo-gravimetric/differential thermal analysis (TG-DTA) and vibrating sample magnetometer (VSM) were carried out in order to synthesize the nanoparticles. Single phase cubic spinel structure of ZnAl2O4 (gahnite) formation was confirmed from the XRD characterization process of the nanoparticles. Estimated average crystallite size range of 11.85 nm to 19.02 nm was observed from Debye-Scherrer. Spherical morphology with uniform distributions was observed from HR-SEM characterization images. From the band gap studies, the attained band gap values were found to lie within 5.41 eV–4.66 eV range. The ZnAl2O4 and Mg:ZnAl2O4 NPs exhibited super-paramagnetic nature confirmed by magnetic measurements. The obtained results make ZnAl2O 4and Mg:ZnAl2O4 NPs appropriate for various optical, catalytic, energy and data storage applications.

Microwave combustion technique (MCT) was used to synthesize of spinel Ni1-xSrxFe2O4 (x = 0.0, 0.1, 0.3 and 0.5) nanoparticles (NPs) by employing the fuel L-arginine. The physical characteristics of the as-prepared NPs were obtained by following methods, viz., powder X-ray diffraction (XRD), high-resolution scanning electron microscope (HR-SEM), energy-dispersive X-ray (EDX), UV-visible diffuse reflectance spectra (UV-Vis DRS), Fourier-transform infrared spectra (FT-IR), and vibrating sample magnetometer (VSM) techniques. The diffraction studies revealed that the average crystallite size exists in the band of 14.25 to 27.52 nm. The HR-SEM pictures revealed the agglomerated and spherical morphology of spinel Ni1-xSrxFe2O4 (x = 0 to 0.5) nanoparticles. Elemental analysis ensured the existence of Ni, Sr, O, and Fe ions. The energy band gap of the NPs was observed to exist in the range of 2.95 to 3.39 eV upon varying the concentration of Sr2+ dopant. The broad peaks at 437 cm−1 and 582 cm−1 correspond to octahedral (B-) metal stretching (Ni-O) and tetrahedral (A-) metal stretching (Fe-O) of nickel ferrite respectively. Magnetic results revealed that the prepared NPs are ferromagnetic in nature. The antibacterial activity (ABA) of gram-positive Staphylococcus aureus and Bacillus subtilis and gram-negative Escherichia coli and Klebsiella pneumonia has been investigated using pure and Sr2+-substituted NiFe2O4 NPs. It was found that the improved activity is intensified with smooth Sr2+ doping as it causes a decrease in the grain size.

Zinc sulfide (ZnS) nanoparticles have been successfully prepared by sol–gel precipitation method. The successful formation of cubic structure is ensured by XRD analysis and Debye Scherrer’s equation is used to determine the crystallite size which was found to be 36 nm for ZnS sample annealed at 200 °C. Surface morphology was studied using HRSEM as well as HRTEM and lattice parameters of the samples were obtained from SAED pattern which was found to have close resemblance to values attained from XRD pattern. Further elemental mapping of ZnS nanoparticles is confirmed by EDX studies. Further Kubelka Munk function was employed to estimate the band gap value which was seen lying within 3.58 to 3.64 eV. Further the antibacterial activity of ZnS is investigated and it is found to be an antibacterial agent of Escherichia coli and staphylococcus aurous, further it can be employed as an antimicrobial agent for prohibiting implant linked infections.

The microwave combustion process (MCP) is used to synthesize Mg1-xCaxFe2O4 (0 ≤ x ≤ 0.5) spinel nanoparticles using the fuel l-arginine. Synthesized samples were examined by employing techniques such as XRD, HR-SEM, EDX, DRS-UV, TG-DTA and VSM. The XRD corroborated the constitution of the cubic spinel structure and the average crystallite size was valued to lie in the range of 16.09 to 33.10 nm. The morphology of the Mg1-xCaxFe2O4 (0 ≤ x ≤ 0.5) spinel nanoparticles was observed by HR-SEM. EDX studies confirmed the formation of spinel ferrite structure. Further bandgap values were estimated to be in the range of 1.84 eV to 2.00 eV. TG-DTA studies confirmed weight loss and exothermic transitions. The M-H loops exhibited ferromagnetic behaviour.

ZnO–CdS nanocomposites with three different molar ratios of 25:75, 50:50 and 75:25 were synthesized by simple hydrothermal technique. Powder X-ray diffraction patterns confirmed the phase formation of ZnO and CdS in ZnO–CdS nanocomposites. The calculated crystallite size was found in the range of 33–38 nm and 15–21 nm for ZnO and CdS respectively. HRSEM images revealed flake-like morphology for all samples. Energy dispersive X-ray spectra confirmed the presence of all the elements. The estimated optical bandgap was found in the range of 3.71–3.35 eV. IR spectra confirmed the formation of stretching vibration in ZnO and CdS. Dielectric analysis was performed in order to study Ac conductivity, dielectric constant and dielectric loss. Photoconductivity studies revealed that ZnO–CdS nanocomposites material exhibited sound photo-response characteristics.

In this work, Magnesium-doped zinc aluminate nanoparticles are synthesized using microwave combustion technique by employing L-alanine as fuel. The incorporation of Mg2+ ions plays a pivotal role in influencing the optical, structural, and magnetic properties of zinc aluminate nanoparticles. The synthesized nanoparticle are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), high-resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM).The XRD patterns confirmed the formation of single-phase cubic spinel structure of ZnAl2O4 (gahnite). The average crystallite sizes estimated from Debye-Scherrer is found to be in the range of 6 to 12 nm. HR-SEM images revealed the spherical morphology with uniform distributions. The optical bandgap of the synthesized nanoparticles is found to be in the range of 5.45 eV–5.76 eV. Magnetic measurement reveals that pure and doped zinc aluminate nanoparticles have superparamagnetic nature. These obtained results of Zn1-xMgxAl2O4 (0 ≤ x ≤ 0.5) are found to be well suited for optoelectronics, magnetic, and catalytic applications.

Zn1-xCoxAl₂O₄ (0 ≤ x ≤ 0.5) nanoparticles were synthesized employing L-alanine as fuel using MACT (microwave assisted combustion technique). The synthesized samples were characterized following methods such as X-ray Diffraction, high resolution scanning electron microscopy, Energydispersive X-ray spectroscopy; UV-visible diffused reflectance spectroscopy, FT-IR and VSM. The XRD confirmed the cubic spinel structure and the average crystallite size observed lying in the range of 12-19 nm deduced using the Debye Scherrer's equation. The morphology of the Zn1-xCoxAl₂O₄ (0 ≤ x ≤ 0.5) nanoparticles is observed using HR-SEM. EDX analysis is opted for the elemental mapping of pure and cobalt doped zinc aluminate nanoparticles. Further band gap value was calculated using Kubelka Munk function, which was seen lying within 3.73 to 5.45 eV. The strong absorption band at 669, 556 and 500 cm-1 was associated with the vibrations of Zn-O, Al-O and Zn-O-Al of zinc aluminate nanoparticles. The hysteresis loops exhibited conversion from diamagnetic into super paramagnetic behaviour with increase in Co doping.

Microwave combustion process is used to synthesize MAl2O4 (M = Zn and Co) spinel nanoparticles utilizing the fuel l -alanine. Synthesized samples were examined by techniques viz. XRD, HR-SEM, EDX, DRS-UV, PL, TG-DTA, FT-IR, XPS and VSM. The XRD confirmed the formation of cubic spinel structure with the average crystallite size of 14 nm and 11 nm for Cobalt and Zinc aluminate nanoparticles respectively. The morphology of CoAl2O4 (CAO) and ZnAl2O4 (ZAO) nanoparticles was observed by HR-SEM. EDX and XPS studies confirmed the formation of pure spinel aluminate structure. Further band gap values were estimated to be 3.35 and 5.45 eV for CAO and ZAO respectively. The PL spectra of CAO and ZAO nanoparticles were studied with an excitation wavelength of 235 and 205 nm. The strong absorption bands between 500-1100 cm-1 were linked to CAO and ZAO nanoparticles. TG-DTA analysis confirmed weight loss and exothermic transitions. The M − H loops revealed CoAl2O4 and ZnAl2O4 nanoparticles exhibited superparamagnetic behavior.

A microwave combustion method was used to synthesize Cu1-xZnxFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) nanoparticles. The synthesized Zn-doped CuFe2O4 nanoparticles were characterized by techniques such as X-ray diffraction, high-resolution scanning electron microscopy, UV–visible diffuse reflectance spectroscopy, photoluminescence spectroscopy, Fourier transform IR spectroscopy, and vibrating sample magnetometry. X-ray diffraction and Fourier transform IR spectroscopy results confirmed the formation of Cu1-xZnxFe2O4(x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) nanoparticles. The crystallite size and lattice parameter were determined as 15–19 nm and 8.319–8.400 A, respectively. High-resolution scanning electron microscopy revealed the presence of agglomerated spherical particles of Cu1-xZnxFe2O4. Elemental mapping of pure and Zn-doped CuFe2O4 was done by energy-dispersive X-ray analysis. The band gap was calculated with the Kubelka-Munk function and was found to lie in the range from 2.30 to 2.51 eV. Finally, M-H curves were plotted and the magnetic properties, such as coercivity, remanent magnetization, and saturation magnetization, were determined.