Sol Gel Auto-combustion Method Research Articles

Controllability of optical, electrical, and magnetic properties of synthesized Cd-doped MgFe2O4 nanostructure

This study explores the synthesis of cadmium-magnesium co-doped magnesium ferrite (Mg1+xCdxFe2–2xO4, 0.00 ≤ x ≤ 0.30, Δx = 0.05) via a citric acid-assisted sol-gel auto-combustion method. X-ray diffraction (XRD) analysis revealed crystal structure changes due to Cd and Mg co-doping, with the 0.25 Cd sample showing the smallest crystallite size and highest lattice strain. High-resolution transmission electron microscopy (HRTEM) confirmed the nanostructure and largest surface area for this sample. Diffuse reflectance spectra, analyzed using the Kubelka-Munk relation, indicated that the 0.25 Cd sample had the lowest energy gap (2.08 eV), supported by band position calculations. Electrical conductivity and charge transport mechanisms were examined at various temperatures. Magnetization studies showed reduced saturation magnetization at x = 0.25, ascribed to cation distribution changes and spin canting, with coercivity and anisotropy decreasing with higher Cd content. Overall, the 0.25 Cd sample exhibited optimized optical, electrical, and magnetic properties due to its distinct microstructure.

Synergetic effect of Hexaferrite and reduced Graphene oxide (rGO) in Photothermal therapy and Hyperthermia applications

This research article describes the synthesis of composite materials by combining T-type hexagonal ferrite and reduced Graphene Oxide using the standard ceramic process. The Calcium-based T-type hexagonal ferrite was synthesized by using the sol-gel auto-combustion method whiles the reduced graphene oxide by adopting the Hummer method. The crystallite size varied in the range of 34.11 to 42.07nm as calculated from the X-ray diffraction (XRD) data. Consequently, the lattice parameters 'a' and 'c' decreased from 5.9 to 5.1Å and from 29.92 to 28.32Å, respectively. The use of atomic force microscopy (AFM) revealed a range of particle sizes at the surface, varying from 1.70nm to 3.85nm. Moreover, the saturation and remanence magnetization values demonstrated an increasing trend with T-type hexaferrites concentration whereas the coercivity decreased. The UV-vis near-infrared spectra exhibited substantial light absorption, characterized by a wide absorption range in the visible and near-infrared (NIR) region (700 to 1100nm) which indicates its use in Photothermal therapy (PTT). The Calcium T- type hexaferrite exhibited clear peaks in the blue, green, violet, and yellow spectra in its photoluminescence (PL) properties. These peaks are believed to be caused by oxygen vacancies and defects. The synthesized samples displayed a lossy behavior in the polarization-electric field (P-E) loop, with saturation polarization levels exceeding remnant polarization, which is an amenable condition for lossy behavior. Most importantly, the synthesized materials had significant thermal responses when exposed to an alternation (AC) magnetic field, indicating their potential use in magnetic hyperthermia applications.

Cerium doped superparamagnetic Mn-Zn ferrite as a promising material for self-regulated magnetic hyperthermia

Recently, cubic ferrites (CF) have been widely explored in biomedical applications, especially those that display superparamagnetism behavior due to the desirable absence of remanent field. In this study, we report the self-stabilization of the magnetic fluid hyperthermia (MFH) temperature in the cancer therapy range (42 - 48 ºC) by Ce3+ substitution in superparamagnetic Mn0.8Zn0.2Fe2-xCexO4 ferrite with x = 0.0; 0.015; 0.030; 0.050 and 0.100. A comprehensive characterization was performed in order to investigate the influence of this replacement on the magnetic and structural properties of the ferrite. The samples were synthesized by the sol-gel auto-combustion method and the properties were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), Raman spectroscopy (RS), Mössbauer spectroscopy (MS), vibrational sample magnetometry (VSM), and ferromagnetic resonance (FMR). Magnetic hyperthermia essays were used to obtain the heat induction curves and calculate energy dissipation. We refined the XRD data by the Rietveld method to determine the cation distribution and calculate interionic parameters. Magnetic characterization confirms the superparamagnetic behavior at 300 K, which is expected from the TEM results that show a narrow distribution of particle sizes, with a mean size of about 6.5 nm for all samples. The VSM results show a consistent decrease in magnetization saturation with cerium content that result in a weaker self-heating induction capacity for the cerium-doped samples. FMR results also show a smaller relaxation time T2 for these samples, suggesting a slower energy dissipation rate. These conclusions are confirmed by the heat induction curves and the values of the specific absorption rate (SAR), which are smaller for cerium-doped samples. For the a field with an amplitude of 35.33 kA/m and a frequency of 222 kHz, the temperature of the cerium-doped samples saturates in the optimum interval for cancer treatment, between 42 and 48 ºC. These results suggest that Ce3+ is a promising doping ion to optimize the heating rate behavior of Mn-Zn ferrite for cancer treatment by hyperthermia.

Transport and magnetic properties of [formula omitted]/Graphene nanoplatelets nanocomposites

A series of Zn0.5Co0.25Cu0.25Ho0.037Fe1.963O4 (ZCCHF)/Graphene nanoplatelets (GNPs) nanocomposites (where GNPs = 0 wt%, 1.25 wt%, 2.5 wt%, 3.75 wt%, 5 wt%) were prepared via sol-gel auto-combustion (SGAC) method followed by bath sonication and studied their structural, morphological, optical, dielectric, and magnetic properties. The structural analysis confirmed a single-phase crystal matrix of all the as-prepared nanocomposites. The optical analysis revealed that the energy bandgap (Eg) lies within the range of 1.57 eV–1.62 eV. The dielectric analysis showed that the improvement in the dielectric constant (ε′) and reduction in dielectric tangent loss (tan δd) with increasing GNPs concentration from 0 wt% to 5 wt%. The real part of permeability (μ′) was improved and magnetic tangent loss (tan δM) was reduced with the addition of GNPs. Magnetic properties were studied at different temperatures (5 K, 300 K, and 400 K), and observed high saturation magnetization (MS), and coercivity (HC) at a low temperature (at 5 K). The low MS, and HC values were observed at high temperatures (300 K and 400 K). The combination of improved dielectric and tunable magnetic properties makes ZCCHF/GNPs nanocomposites promising candidates for applications in spintronics, high-frequency magnetic devices, and advanced electronic systems.

Synthesis, characterisation and functionalization of Hercynite nanoparticles for improved antibacterial activity

Hercynite i.e.,FeAl2O4 is an earth-abundant spinel mineral with a cubic crystal structure and belongs to the normal spinel ferrites possessing optical absorption in the visible range as well as superior magnetic and thermal properties. Herein, we synthesized nanosized FeAl2O4 where the citric acid-mediated sol–gel auto-combustion method was employed to achieve its pure phase and studied its physicochemical properties. Furthermore, the superior colloidal dispersion stability of the FeAl2O4 nanoparticles was achieved required for antibacterial activity and standardised via post-synthesis surface functionalisation using amino-propyl-triethoxysilane (APTES). We further characterised the material using states of art characterisation techniques for their structural, morphological, optical and thermal properties. Finally, the antibacterial activity of pure and surface functionalised FeAl2O4 nanoparticles was investigated against the Escherichia coli (E. coli) strain. We observed good penetration of surface functionalised FeAl2O4 nanoparticles into the bacterial membranes due to the high degree of dispersion achieved via cationic surface charge. Conclusively, a key finding of this study is the enhanced antibacterial properties of surface functionalised FeAl2O4 nanoparticles for the concentration of 31 µg/mL compared to pure FeAl2O4 nanoparticles at 62 µg/mL. This study has great relevance in the area of wound healing and tissue regeneration in the future.

Signature of the Kondo effect in superparamagnetic GO incorporated Cobalt substituted Ni/NiO nanoparticles

The study reports on the magnetization, magnetoresistance, and transport properties of superparamagnetic 10% Co-doped Ni/NiO (C10-NN), Graphene Oxide (GO) incorporated 10% Co-doped Ni/NiO (C10-NNG), and 15% Co-doped Ni/NiO (C15-NN) nanoparticles synthesized via a microwave-assisted sol-gel auto-combustion method. All samples show hysteresis in negative Magnetoresistance (M-R) at different temperatures. Resistivity ρ(T) versus temperature plots of samples C10-NN and C15-NN show metallic behavior with applied fields of 0, 1, 5, 8 T, and at 0 T, 1 T respectively. However, the plot of R-T of the C15-NN sample shows a significant difference at 0 T and 1 T. At 0 T for this sample, the metallic behavior is observed for temperature T > TM, with the resistivity falling abruptly at and above TM = 246 K. The resistivity decreases with increasing temperature, exhibiting metallic behavior again above TMM < 276 K. This jump at 276 K, indicating a metal-to metal transition. The Kondo effect is observed for the first time in C10-NNG sample. The upturn of resistivity ρ(T) towards low temperature in the C10-NNG sample is well described by the power series equation and Kondo term. This sample exhibits the upturn resistivity along with a metal–insulator transition above and below the Kondo temperature TK≈ 93.51(2) K at the 0 T, 1 T, 5 T, and 8 T fields.

Energy band gap tuning of Ba-Ca hexagonal ferrite by Dy3+ ion substitution (0 ≤ x ≤ 0.2) to improve spectral, structural, dielectric and photocatalytic properties

In the present study, Dy3+ substituted M-type Ba0.5Ca0.5DyxFe12-xO19 (0.00 ≤ x ≤ 0.20) hexagonal ferrites were synthesized using sol-gel auto-combustion method with lemon extract as a fuel. The single hexaferrite phase with space group P63/mmc is revealed by the X-ray powder diffraction (XRD) patterns. The Field emission scanning electron microscopy (FESEM) exhibits the agglomeration of nanoplates with vacancies at some places. Energy dispersive X-ray photoelectron spectroscopy (EDAX) mapping confirmed the presence of Ba, Ca, Fe, O, and Dy in the hexaferrite. Fourier Transform Infrared (FTIR) spectroscopy exhibits two characteristic bands at 579 and 429 cm−1 corresponding to tetrahedral and octahedral metal ions-oxygen stretching, revealing the occurrence of the ferrite phase. The optical energy band gap calculated using the Tauc plots was found to increase with the increase in dysprosium substitution to fall within the range of 2.8–3.5 eV. The Raman spectra confirmed the Raman vibration modes and M-type structures of hexagonal ferrites (HFs). The dielectric constant values drop rapidly with increasing frequency up to a few KHz and then gradually for the further higher frequencies. The occurrence of Ba and Ca with 2+, while Dy, and Fe with 3+ oxidation states is confirmed using X-ray photoelectron spectroscopy (XPS). The HFs exhibit remarkable efficiency by degrading the Reactive Brown dye to 99.3 % in just 15 min, equivalent to a high degradation reaction rate constant (k) value of up to 0.0396 min−1. Consequently, the catalyst shows promising potential for environmental remediation.

Microwave absorption by Co/Ce ferrite nanoparticles

Nanosized particles of CoFe2-xCexO4, with 0 ≤ x ≤ 0.29, were synthesized by the sol-gel autocombustion method and the microwave absorption of these ferrites was measured by the Magnetically Modulated Microwave Absorption (MAMMA) method. The results showed that the absorption is highest for a Ce concentration between 0.18 and 0.26, a result that could be useful for practical applications of this material.

Unraveling the structural and magnetic characteristics of Mg doped CoCr2O4

In this paper, we explore the structural and magnetic properties of Mg doped CoCr2O4nanopowder (typical size of 10 nm) synthesized via the sol–gel auto-combustion method. X-ray diffraction, XPS, and FTIR spectraconfirm spinel structure (space group Fd-3 m) with Mg2+ doped at Cr3+. Interestingly, temperature-dependent magnetizations show various magnetic transitions between 5–300 K. While they show ferrimagnetic ordering below Curie temperature of 100 K (CoCr2O4) to 80 K (CoCr1.8Mg0.2O4) samples, the irreversibility betweenFC and ZFC curves at blocking temperature attribute to spin blocking nature of nanoparticles. Finally, at very low temperatures (13–26 K), magnetizations again rise indicating spin-spiral transition of CoCr1.8Mg0.2O4.Furthermore, the effect of these transitions onM−H loopcan be evidentin terms of coercivity, saturation magnetization, andnon-saturation behaviorat high magnetic fields.

Photocatalytic Fenton-like degradation of Acid Green 25 by novel aluminum nanoferrites with persulfate: Optimization by response surface methodology

Magnetic nanomaterials are gaining increasing attention for their catalytic properties and ease of recovery, making them promising candidates for the degradation of various organic pollutants. In this study, AlFe2O4 nanoparticles were employed for the first time in photocatalytic wastewater treatment. The study focused on removing Acid Green 25 anthraquinone dye through persulfate activation under UV-Visible light. AlFe2O4 nanoparticles were synthesized via sol-gel auto-combustion method and characterized by various techniques (XRD, SEM, EDX, VSM, Raman and FTIR). Moreover, statistical analysis of the experimental data confirmed the strong performance of the RSM model in accurately representing the photocatalytic process. Under optimal conditions including persulfate and catalyst concentrations of 0.3 g/L and 0.83 g/L respectively, a solution pH of 3 and 45 minutes of contact time, a 96 % dye removal rate was achieved. The remaining persulfate concentration was 60 % and fully depleted within 90 minutes, indicating efficient activation by AlFe2O4 photocatalyst. The activation process effectively suppressed electron-hole recombination, enhancing the overall efficiency. Scavenger experiments further identified surface-bound radicals and photogenerated holes as the main reactive species. A degradation mechanism for AG25 dye via a photocatalytic Fenton-like process was proposed, highlighting dual synergistic catalysis in the dye degradation. Ecotoxicity assessments using Vibrio fischeri bioassay revealed a significant reduction in toxicity after treatment with AlFe2O4/PS/UV-Vis system. The stability of AlFe2O4 was demonstrated over five degradation cycles. The findings open new perspectives for the use of AlFe2O4 in advanced wastewater treatment technologies, positioning it as a promising material for the degradation of persistent pollutants.

Synthesis of magnetic spinal ferrite CrFe2O4 nanoparticles and uses them to remove lead and cadmium ions from aqueous solutions

Abstract This study deals with the preparation of a magnetic ferrite CrFe2O4 by the sol–gel auto-combustion method, using the lemon juice extract as a fuel for the reaction and preventing the precipitation of the components. The prepared nanocomposite was diagnized using various techniques such as FT-IR, XRD, FE-SEM, EDX, Zeta Potential and (BET). X-ray diffraction patterns verified the state of phase purity and the particle size of 33.9 nm. Additionally the study examined the synthesized compound as an adsorbent surface for lead and cadmium ions from their aqueous solutions. The mathematical formulae of the Langmuir and Freundlich isotherms were applied to the actual adsorption data utilising the findings from the temperature effect studies. As a result, the Freundlich equation yielded a more correlated linear link than the Langmuir isotherm. The thermodynamic results showed that the lead and cadmium ions adsorption were endothermic according to the positive (ΔH) values, whereas the lead and cadmium ion adsorption process were spontaneous with negative (ΔG) values. Positive values of (ΔS) indicate an increase in the randomness of the adsorption process. The current study also comprises the practical application of eliminating lead and cadmium ions from marine waters collected from two sites: Al-Faw Al-Kabir Port (Eastern Breaker) and Khor Al-Zubair (berth 13), by means of the prepared surface. The results indicate the removal percentage of the prepared surface for lead was (91.72%) for the first location and (86.00%) for the second location, whereas the removal percentage of cadmium was (85.52%) for the first site and (89.10%) for the second site.

Cadmium oxide/calcium ferrite nanocomposite-based enhanced electrochemical sensing of metronidazole

The current study aimed to synthesize a cadmium oxide/calcium ferrite nanocomposite (CdO/CaFe2O4–NC) by sol–gel auto-combustion method, then applied on the surface of a glassy carbon electrode to fabricate a (CdO/CaFe2O4–NC/GCE) as a sensor for the electrochemical detection of metronidazole (MNZ). The characterization of synthesized CaFe2O4-NPs and CdO/CaFe2O4–NC was carried out through various analytical techniques, to confirm surface morphology, crystallite nature, average particle size, magnetic behavior, and stability. It is an effective electrochemical method for the detection of MNZ. The fabricated electrode was characterized by cyclic voltammetry, indicating its diffusion-controlled electron transfer behavior. Thus, CdO/CaFe2O4–NC/GCE was used to quantify MNZ using differential pulse voltammetry with a dynamic range of 0.05–130 µM (R2 = 0.0996) and LOD of 0.034 µM. The electrochemical method showed significant stability, sensitivity, and reproducibility (RSD < 4.00 %). The fabricated sensor was successfully applied to the contaminated water samples with quantitative recoveries up to 93.02 % by the spiking method.

Effect of polymer coating on magnetocaloric properties of garnet

In this study, Gd3Fe5O12 nanoparticles were synthesized using the sol–gel autocombustion method and subsequently coated with polyvinylpyrrolidone (PVP) polymer. The study focuses on understanding the influence of PVP coating on garnet particles’ magnetic and magnetocaloric properties. The crystallite size upon PVP-coating remained unaltered, but the grain size and surface area of coated particles increased. The magnetization of PVP-coated particles decreased by around 11% as compared to the uncoated particles at 5 K. Mössbauer and photoelectron spectroscopy confirmed the presence of a paramagnetic phase Fe3+ in the PVP-coated nanoparticles responsible for the reduction in magnetization value. The maximum value of magnetic entropy change (−ΔS m ) for uncoated Gd3Fe5O12 was 3.78 Jkg−1 K−1 at 37.5 K with a 5T applied field, accompanied by a relative cooling power (RCP) of 382 Jkg−1. On the other hand, for PVP-coated Gd3Fe5O12, the maximum −ΔS m was 3.38 Jkg−1 K−1 at 57.5 K with a 5T applied field, and the RCP was 308 Jkg−1. The observed maximum magnetic entropy changes at higher temperatures for the PVP-coated Gd3Fe5O12 sample are noteworthy. This characteristic indicates that the PVP-coated garnet may have an advantage in terms of usability over a wider temperature range compared to the uncoated counterpart, which can potentially be a promising material for applications in cryogenic temperature magnetic refrigeration.

Preparation and Characterization of Pyramids/Particles NiO/SnO2 Composite for Sorption and Separation of Molybdenum and Zirconium Ions from Some Synthetic Fission Products

AbstractPyramids/particles of NiO/SnO2 composite (NS7) was produced by applying the sol–gel autocombustion method. The produced composite was investigated using different techniques, X-ray diffraction, Fourier-transform infrared, Raman spectroscopy, scanning electron microscope, dynamic light scattering, ultraviolet–visible absorbance spectroscopy, and BET surface area then was applied for the adsorption and separation of molybdenum and zirconium ions from lanthanum, strontium, and cesium. 3D pyramids of NiO and particles of SnO2 are confirmed in the composite with a homogeneous mesoporous structure. The composite has good affinity for zirconium and molybdenum ions with fast kinetics and Qmax of 27.1 and 33.3 mg/g, respectively, low affinity for lanthanum, and negligible affinity for strontium and cesium. The sorption mechanism is physical sorption and endothermic in nature. The adsorbed Zr(IV), Mo(VI), and La(III) ions were separated using the desorption process as the following sequence: First, 95 ± 2% (14.3 ppm) of the loaded La was desorbed by washing with double distilled water. Then 96 ± 2% (41.3 ppm) of the loaded Zr was recovered by 1 M potassium chloride without interfering ions. Finally, 98 ± 2% (42.88 ppm) of Mo is desorbed by 1 M sodium acetate solution. The NS7 composite can be reused five times successfully.

Exploring the effect of exchange coupling in (SrFe9.8Al2La0.2O19)1-x/(Co0.7Zn0.3Fe2O4)x nanocomposites synthesised by sol–gel auto combustion method

Extensive research has been conducted over the last decade to develop permanent magnets utilizing less rare earth materials. Exchange-coupled nanocomposite magnets are a fascinating development in the field of permanent magnets. They involve the combination of hard and soft ferrites, resulting in a unique and evolving magnet. Here we present an in-depth structural, morphological and magnetic characterization of ferrite-based nanostructures obtained through a bottom-up sol−gel approach. The combination of high coercivity of a hard phase SrFe9.8Al2La0.2O19 (SFALO) and high saturation magnetization of a soft phase, Co0.7Zn0.3Fe2O4 (CZFO), allowed us to develop exchange-coupled bi-magnetic nanocomposites by varying the mass percentage (x = 0, 0.1, 0.2, 0.3, 0.4, 1). Thermogravimetric analysis (TGA) up to 1200 °C was used to investigate the material’s thermal properties with the phase formation temperature. Detailed atomic/nano-scale structural characterizations of these nanocomposites were performed by X-ray diffraction and Transmission Electron Microscopy. The average particle size was calculated from the SEM analysis and it was observed that most of the composites with ratio x = 0.1, 0.3 & 0.4 was 145 nm and x = 0.2 was 165 nm. The Switching Field Distribution (SFD) curve revealed the exchange coupling between soft and hard magnetic particles. The findings indicate that the inclusion of a soft magnetic phase has a considerable impact on the exchange coupling between the hard and soft ferrite phases. As the spinel concentration increased, in the composite the saturation magnetization increased from 18 emu/g to 48 emu/g. From the stroner-wholfrathmodel, the decrease in the remanence ratio below 0.5 concludes the crystallites are randomly oriented. The nanocomposite with the ratio x = 0.1 was observed with the high magneto crystalline anisotropy of 2183.23 × 102 (J/m3) and a high energy product (BH)max of 5.5 kJ/m3. The aforementioned features of nanocomposites demonstrate their potential for use in permanent magnet applications.

Zn0.5Ni0.5MnxFe2-xO4 magnetically separable nano ferrite: A highly efficient photocatalyst for environmental remediation

The escalating pollution from industries poses a severe threat to water resources, necessitating efficient photocatalysts for environmental remediation. In this study, we introduce a novel Zn0.5Ni0.5MnxFe2-xO4 nano ferrite, synthesized via sol–gel auto-combustion method. The phase purity of Zn0.5Ni0.5MnxFe2-xO4 nano ferrites was confirmed from X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. The microstructural investigation of nano ferrites was investigated using Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). The catalyst’s magnetic properties allow easy separation, addressing the challenge of catalyst retrieval in photocatalysis. Incorporating Zn, Ni, and Mn at tetrahedral and octahedral sites enhances crystallinity, crucial for catalytic efficiency. This mixed metal oxide catalyst demonstrates superior photocatalytic activity, with Zn0.5Ni0.5MnFeO4 exhibiting a remarkable 97% degradation of Reactive Orange (RO) dye under sunlight. Notably, the photocatalyst displays stability and reusability over multiple cycles. The study provides valuable insights into the potential of Zn0.5Ni0.5MnxFe2-xO4 ferrite as a magnetically separable, efficient photocatalyst for environmental remediation.

Structural and magnetic aspects of aluminium substituted dual lanthanum and calcium based hexaferrite nanoparticles for magnetic applications

In the current work, M-type aluminium substituted calcium-lanthanum hexaferrite with chemical formula Ca0.5La0.5Fe12-xAlxO19 (x = 0.00, 0.04, 0.08, 0.12, 0.16) is synthesized by the sol–gel auto combustion method. M-type hexaferrite’s sole-phase crystalline structure was confirmed by X-ray diffraction analysis, which was further used to compute different structural parameters. Structural refinements showed that cell volume decreases from 696.86 Å3 to 692.01 Å3. Moreover, different microstructural parameters are computed, including X-ray density, bulk density, porosity, microstrains and dislocation density. According to VSM analysis, saturation magnetization-(Ms) and remanence magnetization-(Mr) decreased to 17.01 emug−1 and 10.66 emug−1, respectively, while the coercivity increased to 2.165 kOe by increasing the doping concentration to a maximum of x = 0.16. Other magnetic parameters like anisotropy field-(Ha), anisotropy parameter-(B), and magnetocrystalline anisotropy constant-(K), the magnetic moment per formula unit-(µB) were also determined. According to these findings, the synthesized material has excellent potential to be used in magnetic applications.

Synthesis and characterization of micro-/nano-α-Fe2O3 for photocatalytic dye degradation.

Photocatalytic activity using micro-/nano-α-Fe2O3 on a large scale was carried out using a sol-gel autocombustion method. A degradation time of 60 min was noted for 50 mg of the catalyst. Post characterization, this catalyst system showed a degradation of about 53% (rate = 2.60 × 10-3 min-1) and 17% (rate = 1.38 × 10-2 min-1) under sunlight and up to 45% (rate = 1.13 × 10-3 min-1) and 7% (rate = 1.20 × 10-2 min-1) under a 400 W UV lamp for rhodamine 6G (R6G) and crystal violet (CV), respectively. Sunlight has a broad spectrum of light; it greatly accelerates the degradation process and creates ideal conditions for the reaction to occur. The rate of photocatalytic dye degradation of α-Fe2O3 without Fenton's reagent was found to be 7.84 × 10-3 min-1 in the presence of external air provided (in the photocatalytic setup) through a bubbler and 3.23 × 10-3 min-1 in the absence of the bubbler.

Photocatalytic degradation of rhodamine B using Yb3+-Doped Zn-Mg ferrites synthesized via conventional sol-gel auto-combustion method

The primary goal of our research is to develop a photocatalyst capable of degrading organic molecules in water, achieved through the rare earth Yb3+ doping of Zn-Mg spinel ferrites. A key element of our approach is the use of the conventional sol-gel auto-combustion process, which has proven to be an effective method for synthesizing a high-performing, visible light-driven Zn0.9Mg0.1Fe2-xYbxO4 (x = 0.000, 0.015, 0.030, 0.045, 0.060 and 0.075) nano-ferrites. Many analytical techniques were employed to evaluate the material's physicochemical characteristics, including P-XRD, EDX, FE-SEM, HR-TEM, FTIR, UV–vis, BET, VSM, EIS, and photocatalysis was carried out against the RhB. The impact of Yb3+ ion doping on the material's crystallite size and lattice parameter has been evaluated. It was found that all the samples' crystallite sizes increased between 33 and 41 nm. These magnetite nanoparticles have spherical forms and nanometric particle sizes, as revealed through field scanning electron microscopy (FE-SEM). The FTIR spectra bands at ʋ1 (518–535) and (401–411) ʋ2 subsequently revealed the spinel structure of the synthesized nano-ferrites. The band gap in zinc manganese ferrite increases from 2.51 eV to 2.92 eV after adding ytterbium. The surface area of the Yb3+-doped Zn-Mg ferries ranges from 23.6 m2/g to 27.8 m2/g, making them an excellent choice for data storage. The investigation of magnetic behavior shows the superparamagnetic behavior of all the samples. The produced sample's determined squareness value indicates the magnetostatic interaction between the particles. Because of the low produced coercive field value, these materials can be used in ferrofluids and hyperthermia therapy applications. Furthermore, with a higher RhB removal of 93.80 %, the Yb3+-doped sample photocatalyst successfully separated carriers generated by sunlight. The Yb3+-doped sample (ZMY-5) photocatalyst showed outstanding stability after one cycle of the stability test, obtaining an outstanding RhB elimination of 93.80 %. Zn0.9Mg0.1Yb0.075Fe1.925O4 photocatalyst has substantial promise for large-scale pollutant treatment due to its simple synthesis method, superior magnetic characteristics, exceptional photocatalytic activity for RhB, and excellent stability.

The potential of Gd doping as a promising approach for enhancing the adsorption properties of nickel-cobalt ferrites.

The study shows that the addition of gadolinium ions has a significant impact on the structure, morphology, and adsorption properties of Ni-Co spinel ferrite that was synthesized by the sol-gel auto-combustion method. The research also indicates that the higher the Gd content, the greater the increase in the lattice parameter, which suggests that Gd3+ ions uniformly replaced the octahedral Fe3+ ions. The morphology and chemical composition of Gd-doped Ni-Co ferrites have been studied using SEM and EDS. Gd adding to the NiCoFe matrix increases the BET surface area by 50% (from 48 to 72 m2/g) and promotes the formation of mesopores with an average radius from 3.9 to 4.9nm. The pHPZC values of Gd-doped ferrites are in the range of 7.22-7.39, which means that the ferrite surface will acquire a positive charge at natural pH, so this will promote the adsorption of Congo red anionic dye through electrostatic interaction forces. Langmuir, Freundlich, and Dubinin-Radushkevich models were used to explain the mechanism of CR adsorption on the Ni0.5Co0.5GdxFe2-xO4 adsorbent surface. The ionic-covalent parameter has been estimated to describe the surface acid-base properties. Overall, this study highlights the potential of Gd3+ doping as a promising approach for enhancing the adsorption properties of nickel-cobalt ferrites.