Optical, Dielectric, Magnetic, Photocatalytic, and Antibacterial Properties of Ga-Doped BiGaxFe1-xO3 Synthesized by the Microemulsion Approach

The effect of Ga-substitution on bismuth ferrite BiGaxFe1-xO3 (x = 0, 0.05, 0.10, 0.15, 0.20, and 0.25) properties was investigated, which was fabricated using a microemulsion route. X-ray diffraction analysis confirmed that specimens had a single-phase rhombohedral structure with space group R3̅c. The concentration of Ga had an impact on various properties such as structural parameters, crystalline size, porosity, and unit cell volume. The samples exhibited notable values for the dielectric constant, tangent loss, and dielectric loss in the low-frequency range, which declined as the frequency increased due to different polarizations. The increment in the AC conductivity was associated with rise in frequency. The P-E loops demonstrated that the samples became more resistive as the Ga concentration increased. The retentivity (Mr) and saturation magnetization (Ms) values reduced as the Ga content increased, although all samples had Hc values within the range for electromagnetic materials. The Ga-substitution had a synergistic effect on the electrochemical characteristics of BiGaxFe1-xO3, resulting in greater conductivity than that of undoped BiFeO3. These enhanced properties contributed to their higher photocatalytic activity in the degradation of crystal violet under visible light irradiation. The doped BiGaxFe1-xO3 exhibited 79% dye degradation after 90 min of illumination compared to 54% for pure BiFeO3. Recycling experiments confirmed the stability and reusability of the synthesized nanoparticles. The antibacterial activity of the samples was certified against various microbes, and the doped BiGaxFe1-xO3 showed promising activity. Thus, doped materials are good candidates for memories, dielectric resonators, and photovoltaics because of their high dielectric constant and AC conductivity, while their higher photocatalytic activity under visible light makes them promising photocatalysts for removing noxious and harmful effluents from wastewaters.

Cationic distributions and dielectric properties of magnesium ferrites fabricated by sol-gel route and photocatalytic activity evaluation

Sol-gel auto combustion method was adopted to fabricate magnesium ferrite (MgFe2O4) nanoparticles. The structural and morphological properties was studied by XRD, FTIR, and SEM analysis. The average particle sizes of MgFe2O4 was in the range of 35–55 nm. The octahedral & Tetrahedral bond lengths, R AE (tetrahedral edge length), R BE (shared octahedral edge length) and R BEU (individual octahedral edge length), cationic radii (tetra and octa-sites) were also determined. The magnetic strength also showed direct reliance on bond angle and indirect to bond length. Hoping length L a and L b and bond angles are also measured. The frequency dependent conductivity and dielectric properties of MgFe2O4 were investigated by Impedance analyzer. The photocatalytic activity (PCA) is appraised against MB (methylene blue) dye and MgFe2O4 calcined at 800 °C showed promising degradation (78%) under visible light irradiation. The findings revealed that MgFe2O4 is can harvest the solar light, which could be employed for the remediation of wastewater contains textile dyes.

Green synthesis of iron nanoparticles and photocatalytic activity evaluation for the degradation of methylene blue dye

The present study focuses on iron nanoparticles (Fe NPs) biosynthesis, characterization and photocatalytic activity (PCA) appraisal for methylene blue dye degradation. A green rapid biogenic synthesis route was employed for synthesis of Fe NPs using banana peel extract. The synthesized Fe NPs was characterized by XRD (X-ray diffraction), SEM (scanning electron microscopy) and EDX (energy dispersive X-ray) techniques. These analysis confirmed the synthesis of zero valent Fe NPs with high crystallinity, purity and semi spherical in shape. The photocatalytic activity was assessed under ultra violet irradiation and under optimum conditions, 87% degradation of MB dye was obtained for 72 min of irradiation, which revealed promising catalytic efficiency of the Fe NPs. The result shows that photocatalytic activity of Fe NPs is promising and could possibly be used to treat dyes in industrial effluents and the use of green synthetic protocol is suggested due to its ecofriendly nature.

Size controlled synthesis of silver nanoparticles: a comparison of modified Turkevich and BRUST methods

In the present investigation, silver nanoparticles were synthesized and a comparative analysis was performed of modified Turkevich and BRUST methods. Silver nitrate precursor was reduced by trisodium citrate dihydrate and ascorbic acid was used as a surfactant. Based on Turkevich and BRUST methods, the process variables, i.e., temperature, reducing agent concentration, stirring speed, mode of injecting reducing agent/precursor to large excess volume of either precursor/reducing agent were studied. The size of the particles was preliminarily ascertained by DLS studies and it was found that modified BRUST method yielded silver nanoparticles with average particle size of 25 nm, while modified Turkevich method furnished nanoparticles with average particle size of 15 nm. The silver nanoparticles were characterized by employing the UV/visible, Zeta sizer, scanning electron microscopy (SEM) and energy dispersive microscopy (EDX) techniques. Results revealed that the silver nanoparticles size can be controlled by optimizing the conditions of modified Turkevich and BRUST methods.

Fabrication of Mn3O4-CeO2-rGO as Nanocatalyst for Electro-Oxidation of Methanol

Recently, the use of metal oxides as inexpensive and efficient catalysts has been considered by researchers. In this work, we introduce a new nanocatalyst including a mixed metal oxide, consisting of manganese oxide, cerium oxide, and reduced graphene oxide (Mn₃O₄-CeO₂-rGO) by the hydrothermal method. The synthesized nanocatalyst was evaluated for the methanol oxidation reaction. The synergetic effect of metal oxides on the surface of rGO was investigated. Mn₃O₄-CeO₂-rGO showed an oxidation current density of 17.7 mA/cm² in overpotential of 0.51 V and 91% stability after 500 consecutive rounds of cyclic voltammetry. According to these results, the synthesized nanocatalyst can be an attractive and efficient option in the methanol oxidation reaction process.

Kinetics of acid blue 40 dye degradation under solar light in the presence of CuO nanoparticles synthesized using Citrullus lanatus seeds extract

In view of eco-benign nature of green synthesis, in the present investigation, the CuO NPs are prepared using Citrullus lanatus seeds extract and photocatalytic degradation efficiency for Acid Blue 40 (AB-40) was evaluated. The CuO NPs were characterized by XRD (X-ray diffraction), SEM (scanning electron microscopy), EDX (energy dispersive X-ray), and FT-IR (Fourier transform infrared) techniques. The synthesized CuO NPs was in face centered monoclinic crystalline form with particle size in 40–60 nm range. The photocatalytic degradation potential of CuO NPs was assessed for acid blue 40 (AB-40) dye degradation and catalyst dose, concentration of dye, radiation exposure time and pH are considered for dye removal. The CuO NPs exhibited auspicious efficiency, an 84.89% dye removal was attained at optimal conditions and dye degradation followed BMG (Behnajady–Modirshahla–Ghanbery) kinetics model. Results revealed CuO NPs synthesized using C. lanatus seeds extract is photoactive catalyst and green route can be employed for CuO NPs fabrication for photocatalytic applications.

Cephradine drug release using electrospun chitosan nanofibers incorporated with halloysite nanoclay

The chitosan/polyvinyl alcohol/halloysite nanoclay (CS/PVA/HNC) loaded with cephradine drug electrospun nanofibers (NFs) were fabricated and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) techniques. FTIR analysis confirmed the hydrogen bonding between the polymer chain and the developed siloxane linkages. SEM analysis revealed the formation of uniform NFs having beads free and smooth surface with an average diameter in 50–200 nm range. The thermal stability of the NFs was increased by increasing the HNC concentration. The antimicrobial activity was examined against Escherichia  coli and staphylococcus strains and the NFs revealed auspicious antimicrobial potential. The drug release was studied at pH 7.4 (in PBS) at 37 °C. The drug release analysis showed that 90% of the drug was released from NFs in 2 h and 40 min. Hence, the prepared NFs could be used as a potential drug carrier and release in a control manner for biomedical application.

State-of-art of silver and gold nanoparticles synthesis routes, characterization and applications: a review

To date, the noble metal-based nanoparticles have been used in every field of life. The Au and Ag nanoparticles (NPs) have been fabricated employing different techniques to tune the properties. In this study, the methodologies developed and adopted for the fabrication of Au and Ag have been discussed, which include physical, chemical and biological routes. The Au and Ag characteristics (morphology, size, shape) along with advantages and disadvantages are discussed. The Au and Ag NPs catalytic and biomedical applications are discussed. For the Ag and Au NPs characterization, SEM (scanning electron microscope), TEM (transmission electron microscope), FTIR (Fourier transform infra-red spectroscopy), XRD (X-rays diffraction) and DLS (dynamic light scattering) techniques are employed. The properties of Au and Ag NPs found dependent to synthesis approach, i.e., the size, shape and morphologies, which showed a promising Catalytic, drug delivery and antimicrobial agent applications. The review is a comprehensive study for the comparison of Au and Ag NPs synthesis, properties and applications in different fields.