Sol Gel Auto-combustion Method Research Articles

Effect of Cr3+ substitution on the structural and magnetic properties of Co-Cu-Zn nano ferrites

Nano-ferrite materials with chemical compositions Co0.5Cu0.45Zn0.05Fe2-xCrxO4 (x = 0.0, 0.05, 0.1, 0.15, 0.2, and 0.25) (Co-Cu-Zn) nano ferrite materials were synthesized through the sol–gel auto-combustion method, and analytical characterizations of their structural and magnetic properties were conducted. Utilizing the Debye-Scherrer equation, the average crystallite sizes of the synthesized samples were determined to range from 37.25 nm to 53.56 nm, and X-ray diffraction (XRD) examination verified the synthesis of a single-phase cubic spinel structure. Microstructural and morphological properties were investigated using Field-Emission Scanning Electron Microscopy (FESEM) scanning, revealing grains in the nano-scale range. Two distinct peaks were observed at approximately 595 cm−1 and 392 cm−1, providing information about the functional groups of the samples’ chemical characteristics according to Fourier transform infrared analysis (FTIR). Room temperature vibrating sample magnetometer (VSM) analysis provided magnetic information on the materials, presenting various values of magnetic parameters. The samples’ hysteresis curves showed that the saturation magnetization and coercivity almost decreased when the dopant concentration in the host Co-Cu-Zn is increased.

Sol-gel synthesis of Cobalt-Bismuth substituted strontium hexaferrites and insight into structural refinement, Microstructural, dielectric and spectroscopic properties

Bi and Co-substituted strontium (SrFe12O19) hexaferrites were synthesized using the auto-combustion sol–gel method. The structural, Rietveld refinement, microstructural, spectroscopic, and dielectric characterizations were analyzed with X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and Dielectric analysis, respectively. The XRD investigation of Sr1-xBixFe12-yCoyO19 with (x = 0–0.5, y = 0–1.0) confirmed the single phase of M−type hexagonal ferrites. The change in the value of lattice constant ‘a’ in between 5.87 and 5.95 and ‘c’ 22.07 to 23.81 to be noted. The crystallite size of prepared specimens was determined in (20–29) nm range. The specific stretching vibrations in the FTIR results approves (Fe/Co-O and Bi-O) at three different positions 437.59, 549.94, and 587.53 cm−1. The existence of these band from 437 to 588 cm−1 confirmed the hexagonal structure of these ferrites. The force constants at octahedral sites increased from 1.75 to 2.02 (Dyne cm−1) x 105 and shows insignificant behavior at tetrahedral sites in between (3.33–3.54) Dyne cm−1 x 105 with Bi-Co substitution. The first band 582 cm−1 (ʋ1), is due to the maximum restoring force and vibrations at the tetrahedral site. The second band at a lower wavenumber of ∼ 402 cm−1 (ʋ 2) is due to the vibrations at the octahedral site. The microstructure of all synthesized samples of M−type hexagonal ferrites confirmed using the SEM analysis. The dielectric measurements in 0 to 3 GHZ frequency was done and effect of Bi-Co has been observed. The dielectric constant of all specimens shows the increasing trend from 1.5 GHz to 2.5 GHz with the frequency of the applied AC field. A slight increase was observed in the AC conductivity of these ferrites with the increasing concentration of Bi and Co ions.

Green synthesis of NiFe2O4, CoFe2O4, and Ni0.5Co0.5Fe2O4 by sol–gel autocombustion method using olive leaf extract as fuel

Green synthesis of NiFe2O4, CoFe2O4, and Ni0.5Co0.5Fe2O4 by sol–gel autocombustion method using olive leaf extract as fuel

Strong correlation of electrical transport and magnetic properties to ionic states, structure, and morphology of Al-substituted Ni–Co ferrite systems: A comprehensive study

This paper presents the structure, morphology, magnetic, ionic states, and electrical transport characteristics of spinel Ni0.5Co0.5AlxFe2-xO4 (x = 0.0, 0.5, and 1.0) nanocrystalline ferrites, synthesized by using the sol-gel auto-combustion method. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to analyze the structural characteristics. The synthesized ferrites were found to have a crystallite size of less than 40 nm when the Rietveld method was applied to refine XRD patterns in single-phase cubic spinel-related structures that belong to the Fd-3m space group. Furthermore, since the ionic states are visible in X-ray photoelectron spectroscopy (XPS), variations in Al3+ ion concentration have been found to affect the locations, occupancy, and Wyckoff's cationic position of the ions as well as the lattice constant (a), the crystallite size (D), and the micro-strain of the composites. Thermogravimetric analysis was used to examine the temperature-dependent spinel phase formation and % weight loss of the sample. The x = 1.0 composition is said to be the best dielectric material out of the three samples since it has the highest polarization permittivity, the lowest dissipation factors, and exceptional temperature stability. These nanoparticles have relatively high impermanent magnetization values and are ferrimagnetic, according to the vibrating sample magnetometer (VSM) investigation. Additionally, it was found that the presence of Al3+ decreases the magnetization values of the spinel Ni0.5Co0.5AlxFe2-xO4 (x = 0.0, 0.5, and 1.0) system because the Al3+ exclusively occupies the Fe-sites, which reduces the super-exchange interaction between the Fe2+/Fe3+, Co2+/Co3+, and the Ni2+/Ni3+ ions. The unique magnetic characteristic of these compositions below 40 nm is predicted to make them appealing for storage applications.

Rietveld refined structural and sintering temperature dependent electromagnetic properties of Al3+ substituted Ni–Co ferrites prepared through sol–gel auto combustion method for high-frequency and microwave devices

Rietveld refined structural and sintering temperature dependent electromagnetic properties of Al3+ substituted Ni–Co ferrites prepared through sol–gel auto combustion method for high-frequency and microwave devices

Enhancing hydrogen generation from sodium borohydride hydrolysis and the role of a Co/CuFe2O4 nanocatalyst in a continuous flow system

In this study, a series of cobalt-based spinel ferrites catalysts, including nickel, cobalt, zinc, and copper ferrites, were synthesized using the sol–gel auto-combustion method followed by a chemical reduction process. These catalysts were employed for accelerating hydrogen generation via the sodium borohydride hydrolysis process. A continuous stirred tank reactor was used to perform catalytic reactor tests. All samples were subjected to analysis using XRD, FESEM, EDX, FTIR, and nitrogen adsorption–desorption techniques. The results revealed that the cobalt-based copper ferrite sample, Co/Cu-Ferrite, exhibited superior particle distribution, and porosity characteristics, as it achieved a high hydrogen generation rate of 2937 mL/min.gcat. In addition, the higher electrical donating property of Cu-Ferrite which leads to the increase in the electron density of the cobalt active sites can account for its superior performance towards hydrolysis of NaBH4. Using the Arrhenius equation and the zero-order reaction calculation, activation energy for the sodium borohydride hydrolysis reaction on the Co/Cu-Ferrite catalyst was determined to be 18.12 kJ/mol. This low activation energy compared to other cobalt-based spinel ferrite catalysts confirms the catalyst's superior performance as well. Additionally, the outcomes from the recycling experiments revealed a gradual decline in the catalyst's performance after each cycle during 4 repetitive cycles. The aforementioned properties render the Co/Cu-Ferrite catalyst an efficient catalyst for hydrogen generation through NaBH4 hydrolysis.

Preparation and structure investigation of polyethylene terephthalate polyester reinforced Ni0.5Zn0.5Fe2O4 nanoparticles for gamma ray shielding performance

Defects of high atomic materials gamma-ray shielding such as low chemical stability, low mechanical properties, and heaviness lead us to investigate other light and flexible materials such as polymers. Polymer-doped nanosized materials are the most frequently examined materials. In this study, polyethylene terephthalate [(C10H8O4)n] was doped with Ni0.5Zn0.5Fe2O4 nanoparticles up to 40 wt% (0.0, 10.0, 20.0, 40.0 wt%) prepared by Sol–Gel auto-combustion method with the help of Gelatin. The polyester/Nanofiller composite structures were identified using x-ray photoelectron spectroscopy, x-ray diffraction, Scanning, and Transmission electron microscope as well as density measurements. x-ray photoelectron spectroscopy confirmed the successful doping of nanofiller in the polyester structure as Zn signals appear in the atomic composition and Fe signals appear in the deconvolution of the peaks. x-ray diffraction, transmission, and scanning electron microscope display the same result. x-ray diffraction graph information with the Scherer equation offered the crystal size of the composite (26 nm). Polyester/nanofiller samples were scanned against gamma-ray and experimental shielding factors were computed using a narrow beam transmission technique with sodium iodide detector and two-point sources Cs-137 and Co-60. Experimental Linear and mass attenuation coefficient values swelled as percentages of nanofiller increased in the polyester structure. Experimental Mass attenuation values were compared with theoretical ones estimated from XCOM and Physics-X programs. The difference between them does not exceed 12% which is acceptable as the x-ray photoelectron spectroscopy atomic composition utilized in the theoretical data calculation does not reveal Ni signals. This may occur at the depth of the composite structure. Finally, the half-value layer, the Tenth value layer, and the Mean free path are determined experimentally, and their values are reduced as the nanofiller doping percentage rises in the structure. This result confirms the efficiency of nanofiller addition to the polyester structure to attenuate gamma-ray.

Exploring the impact of annealing temperature on morphological, structural, vibrational and electron paramagnetic resonance properties of starch-mediated spinel CoAl2O4: Experimental and DFT study

In the present work, CoAl2O4 nanoparticles were successfully synthesized using the simple auto-combustion sol-gel method employing starch as an organic fuel source. The effect of the annealing temperature on the structural, vibrational, morphological, and magnetic properties is studied. The obtained spherical nanoparticles have grain sizes ranging from 23.54 nm to 46.50 nm. X-ray diffraction (XRD) patterns reveal the formation of a face centered cubic (fcc) spinel phase with the Fd-3m space group for all prepared samples. The calculated average crystallite sizes exhibit an increase from 24.65 nm to 56.27 nm, consistent with the observed grain sizes. Density Functional Theory (DFT) calculations are applied to reach the optimized cell parameters as well as to confirm the structural properties of the synthetized CoAl2O4 nanoparticles. Geometry optimization of the CoAl2O4 spinel oxide is performed using the CASTEP module of Materials Studio software. The optimized unit cell, lattice parameter and unit cell volume were obtained from this simulation. The combined experimental and density functional theory study of structural properties of CoAl2O4 revealed that an increase in the calcination temperature leads to an increase in the volume of the unit cell and hence to an increase in the particles size. Fourier-transform infrared spectroscopy (FTIR) further corroborated these findings by demonstrating subtle shifts in characteristic CoAl2O4 absorption peaks with varying annealing temperatures. These peak shifts suggest a potential redistribution of Al³⁺ and Co2⁺ ions between tetrahedral and octahedral sites within the spinel structure. Electron paramagnetic resonance (EPR) spectroscopy revealed a magnetic state transition as a function of both the annealing temperature and the resulting crystallite size. Occupancy fluctuations of Al³⁺ and Co2⁺ ions at specific sites have also impacted on the nanoparticles color since the hue of the material depends on the valence state and the cationic coordination environment in the CoAl2O4 crystal lattice. Correlations between structural, vibrational, magnetic and color properties are presented to understanding how synthesis parameters influence CoAl2O4 characteristics which is essential for tailoring materials for specific applications.

Zinc oxide and nickel ferrite nanocomposite as an efficient photocatalyst for crystal violet dye degradation

In the present study, photocatalytic activity of NiFe2O4/ZnO nanocomposite was studied for the degradation of crystal violet dye. Microwave assisted green synthesis method was used for the synthesis of ZnO nanoparticles (NPs). Sol-gel auto-combustion method was used to synthesize NiFe2O4 (NiF) NPs. NiF/ZnO nanocomposite was synthesized through solid-state reaction method. Structural phase was confirmed through X-ray diffraction studies. ZnO NPs were found in wurtzite hexagonal structure whereas cubic spinel structure was found for NiF. NiF/ZnO nanocomposite was observed in both phases. The crystallite size was found to be 31 ± 1, 18 ± 2 and (95 ± 1)/(98 ± 1) nm, for NiF, ZnO and NiF/ZnO nanocomposite, respectively. The optical band gap was determined through UV–Visible spectroscopy and is found to be 1.67 ± 0.03, 2.70 ± 0.08 and 1.70 ± 0.05 eV for NiF, ZnO and NiF/ZnO nanocomposite, respectively. Infrared study of NiF showed the tetrahedral and octahedral band whereas for ZnO the characteristic band was observed. FESEM micrographs of NiF/ZnO nanocomposite showed the formation of agglomerated spherical particles and very less number of rod-like grains indicating the formation of NiF/ZnO nanocomposite. The photocatalytic activity of NiF, ZnO and NiF/ZnO nanocomposite for the degradation of crystal violet dye was studied. It was found that NiF, ZnO and NiF/ZnO nanocomposite showed 89 %, 90.46 % and 87.21 % degradation rate in 60, 120 and 50 min respectively.

Universal Dielectric Response in Electronically Correlated Functional Oxides CaCu3Ti4O12, LaFeO3, YFe0.5Cr0.5O3 and their Nanocomposites: A Comparative Study

AbstractCaCu3Ti4O12 (CCTO), LaFeO3 (LFO) and YFe0.5Cr0.5O3 (YFCO) were synthesized via conventional sol–gel auto–combustion method using citric acid as gelling agent. The X‐ray diffraction analysis revealed the phase purity of the samples. The energy dispersive X‐ray (EDX) analysis confirms the stoichiometry of the pristine phases. The average particle size obtained from the field emission Scanning electron microscopy (FE−SEM) images revealed that CaCu3Ti4O12 exhibits a broad range of particle size starting from a couple of hundreds of nanometer to micrometer, whereas that for LaFeO3 and YFe0.5Cr0.5O3 are about 110 nm and 50 nm, respectively. We have fabricated the new composites: CCTO–LFO, CCTO–YFCO and LFO–YFCO. The grain sizes of the composite phases are consistent with the pristine phases as they are prepared by at lower sintering temperatures and duration. The dielectric properties of these ceramic composites were compared to those of the pristine phases. The temperature and frequency dependent dielectric measurements reveal a wide range of dielectric constant with moderate tan δ values. The temperature dependent dielectric constant of the investigated samples varies from 100 to 1500 at room temperature and the data have been analyzed using universal dielectric response (UDR) model.

Investigation of structural, electrical, and magnetic variations of Ni-Zn-Co ferrites by substituting rare earth Ho3+ for high-frequency applications

The investigation of structural, magnetic, and electrical properties of Ni0.6Zn0.3Co0.1HoxFe2−xO4 (NZCHF, 0 ≤ x ≤ 0.2) ferrites, synthesized through the sol–gel autocombustion method, has been undertaken. The refined x-ray diffraction (XRD) analysis was performed for XRD data analysis using Fullprof Suite software and it confirmed a single-phase cubic spinel structure, with the determination of crystallite size, refinement parameters and lattice constants. The bulk density of the samples consistently remained lower than the x-ray density, with densities increasing proportionally to the enhancement of Ho concentration. FTIR analysis corroborated the presence of metal-oxygen bonds within the ferrite possessing a spinel cubic structure. 57Fe Mossbauer spectroscopy showed that the hyperfine magnetic field of tetrahedral (A) and octahedral (B) sites decreased with the substitution of Ho3+ ions that preferentially occupy the B site. The impedance analyzer and vibrating sample magnetometer (VSM) were utilized to measure the real and imaginary parts of the complex permeability and magnetic properties of the samples, respectively. Complex impedance plots were scrutinized to discern the contributions of grain and grain boundary resistances, providing insights into the electrical behavior of the ferrite samples. Furthermore, the introduction of Ho concentration led to alterations in other key properties of the ferrites, including coercivity (H c ), retentivity (M r ), anisotropy constant (K), and magnetic moment (μ B ).The impact of the rare-earth content on the magnetic features of the prepared NiZnCo ferrite microspheres was investigated by analyzing magnetic-hysteresis (M-H) loops, which showed soft ferrimagnetism. Concurrently, the dielectric constant and dielectric loss tangent of the studied samples exhibited a decrease with the rise in Ho3+ concentration. The expected reduction in tan loss in the prepared samples is attributed to the increase in ac resistivity associated with the higher Ho3+ content.

Sol-gel auto-combustion synthesis of bimetallic Pt-Co/Al2O3 catalysts for hydrogen production via acetic acid steam reforming

Green hydrogen production from renewable biomass via bio-oil catalytic steam reforming was a prospective technology. In order to accelerate the development of high-performance and long-term catalyst, we selected acetic acid as a typical bio-oil model compound to carry out the studies of steam reforming. Excellent bimetallic Pt-Co/Al2O3 catalysts were prepared using a sol-gel auto-combustion method. The effects of the molar ratio of ethylene glycol: citric acid: metal ions (EG/CA/M) on the catalyst structure and subsequent reforming performance were systematically investigated. It was found that the catalyst’s textural properties, reducibility, basic sites, and the dispersion of active metal could be carefully tuned by the EG/CA/M ratio. The catalyst prepared under EG/CA/M ratio of 6:3:1 performed the best reactivity in acetic acid steam reforming, showing a 97.6% acetic acid conversion and a 96.6% H2 yield at the reaction conditions of 650 °C, steam to carbon molar ratio of 5, and space velocity of 6957 h–1. Furthermore, a bifunctional reaction mechanism of acetic acid catalytic steam reforming was proposed by in-situ diffuse reflective infrared Fourier transform spectroscopy analysis coupled with density functional theory calculations.

Effect of synthesis on structural, vibrational, and electrical properties of Ba1−xCaxCe0.8Nd0.2O3−δ (BCCN, 0 ≤ x ≤ 0.01) synthesized by sol–gel auto combustion method

Effect of synthesis on structural, vibrational, and electrical properties of Ba1−xCaxCe0.8Nd0.2O3−δ (BCCN, 0 ≤ x ≤ 0.01) synthesized by sol–gel auto combustion method

Influence of Zirconium substitution on electrical properties of Nickel-Zinc Ferrites

The Zirconium substituted Nickel Zinc Ferrite nano particles with chemical composition of Ni(0.5-x)Zn(0.5-x)ZrxFe2O4, where the value of x varies from 0 to 0.2, have been synthesized by the sol-gel auto combustion method, using high purity nitrates and fuelling agent citric acid. The structural property was studies from X-ray diffraction spectra. The crystallite size decreases with increase in Zirconium substitution. The electrical property of the same was investigated by studying the dielectric constant, and AC conductivity. There are fluctuations in these properties with variation in Zirconium substitution in Ni-Zn Ferrite.

Synthesis and characterization of NiFe2 O4 nanoparticles by tartaric acid assisted sol-gel auto-combustion method

Nickel ferrite nanoparticles were synthesized by modified sol-gel auto-combustion method. The final product obtained was annealed at 600 °C. The thermal, structural, morphological, vibrational, optical and magnetic properties were studied using TGA, XRD, SEM, FTIR, UV-DRS and VSM techniques, respectively. The thermo gravimetric analysis shows three step decomposition of residual nitrate and tartrate complexes with a total weight loss of 6.69% below 600 °C. Further, there was no significant weight loss above 600 °C. XRD confirmed the spinel cubic phase with Fd3m space group. The average crystallite size was 14 nm. An agglomerated random morphology with porous flake like microstructure was observed. The vibrational analysis confirmed the presence of Ni-O, Fe-O stretching vibrational modes in the wave number range 400-600 cm−1. Tetrahedral site (kTd) and octahedral site (kOh) force constant values were 2.20×105 and 1.31×105 dynes/cm, respectively. From UV-DRS spectra, the Kubelka-Munk function was used to calculate the optical band gap and it was 1.71 eV. The magnetic saturation, retentivity and coercive field values: Ms = 22.35 emu/gm, Mr = 5.20 emu/gm, Hc = 165 Gauss were obtained from VSM analysis. The calculated magnetic moment value was 1.115 μB. The law of approach to saturation was employed to analyze the VSM data in saturation region. The calculated magneto-crystalline anisotropy constant, K1 value was 0.857×105 erg/cc.

Enhanced magneto-dielectric characteristics of Ni–Cd ferrites/GNPs composites synthesized via sol-gel auto-combustion method

Graphene nanoplatelets (GNPs) and spinel ferrites (SFs) composites enhance their properties and enable multifunctional applications, ranging from electronics to environmental and biomedical fields. This study investigates the Ni0.4Cd0.6Fe2O4/x-GNPs (x = 0 %, 2.5 %, and 5 %) [NCF/0%GNPs, NCF/2.5%GNPs, and NCF/5%GNPs] composites prepared via sol-gel auto combustion (SGAC) synthesis and their enhanced magneto-dielectric characteristics. XRD analysis confirmed the formation of a single-phase spinel matrix of NCF/GNPs composites and observed that the crystallite size (D) was enhanced from 22.8 nm to 33.6 nm with the increasing concentration of GNPs. Moreover, the bandgap energy (Eg) was reduced with the incorporation of GNPs in the NCF sample. The dielectric constant and tangent loss were enhanced with the addition of GNPs in the NCF spinel lattice. The saturation magnetization and microwave operating frequency were reduced from 97.42 emu/g to 55.13 emu/g and 21.49 GHz–11.97 GHz, respectively, while the coercivity was observed to increase from 92.66 Oe to 263 Oe with the incorporation of GNPs in the NCF lattice. The study highlights the potential of NCF/GNPs composites for applications in electronics, energy storage, sensors, and biomedical devices.

Influence of Pr-cations on structural, spectral, elemental, and electrical features of Zr2–R type ferrites

Hexagonal ferrites have gained much attraction due to extensive applications in telecommunication and stealth fields. R-type hexagonal ferrites are rare hexagonal ferrites used in various technological applications. In the current work, the sol-gel auto-combustion method was used to prepare samples of R-type hexagonal ferrites with the chemical formula BaZr2Fe4-xPrxO11 (x = 0.00, 0.03, 0.06, and 0.09) respectively. The impact of substituting Praseodymium (Pr) on its structural, electrical, dielectric, and magnetic properties was investigated. X-ray diffraction (XRD) patterns suggest all samples exhibit a single phase. The lattice parameters and unit cell volume experienced alterations with varying Praseodymium (Pr3+) substitution levels. The atomic dynamics study of the Pr-doped R-type hexagonal ferrites was evaluated using FTIR analysis. Two absorption bands in the infrared spectroscopy were utilized to designate the tetrahedral and octahedral sites. X-ray photoelectron spectroscopy (XPS) findings verified the presence of all metal ions alongside their respective electronic states. Jonscher's power law elucidates the conduction mechanism of charge carriers in the synthesized ferrite samples. Impedance analysis was employed to investigate the influence of relaxation time and grain boundaries on the electrical characteristics of the fabricated nanomaterials. Impedance Cole-Cole plots provide evidence that all samples demonstrate multiple relaxation processes of a non-Debye nature. The minimum reflection loss (RL) of −32.46 dB at 3.27 GHz was achieved for x = 0.09. Pr-doped R-type hexagonal ferrite has potential applications in microwave high-frequency applications.

Structural, magnetic, impedance and electric modulus response and dielectric relaxation in Co-doped inverse spinel [formula omitted] nanoferrite

In this research work, we report synthesis, structural, electric and magnetic properties of Cu1−XCoXFe2O4(x = 0.05, 0.10, 0.15, 0.20) nanoferrite. All the samples are synthesized using sol-gel auto-combustion method. X-ray diffraction patterns validate the formation of single phase tetragonal structure at room temperature for all the samples. Absence of secondary phases confirms the successful substitution of Cu2+ by Co2+ ions in CuFe2O4 matrix. Dielectric analysis reveals that all the materials exhibit remarkable single dielectric relaxation. The dielectric relaxation peaks are observed between 150–225 °C. In addition, Co-doped CuFe2O4 exhibit marked enhancement of dielectric constant value for potential technological applications. Further, the correlated barrier hopping (CBH) model well explains the conduction phenomena in all the samples. Activation energy values are analyzed by applying the Arrhenius equation. Impedance analysis indicates that both grain and grain boundary effects contributed the electrical response in the ferrites which is confirmed from the plot of Z″ vs. Z′. The bulk and grain boundary response are further determined by modeling the impedance data with an equivalent circuit. Modulus study confirms the existence of non-Debye type of relaxation in the synthesized ferrites. Magnetic study shows the improved value of magnetic parameters such as saturation magnetization (Ms), remanent magnetization (Mr) and coercive field (Hc).

Performance boosting of Sb2Se3 photodetectors by a sol–gel auto-combustion ZnO overlayer

Antimony selenide (Sb2Se3) is a promising material for low-cost, high-performance optoelectronic devices. In this study, a sol–gel auto-combustion ZnO overlayer was introduced into the Sb2Se3 photodetector (PD) for the first time. The sol–gel auto-combustion method is simple, efficient and low-cost, and when the solution ratio of the ZnO overlayer (Zn(CH3COO)2·2H2O: Zn(NO3)2·6H2O) is optimized to 6:4, the constructed heterojunction improves the electron transport efficiency and shows the best performance. The results showed that the ameliorated PD exhibits higher on/off ratio (6054), responsivity (R) (23.5 mA W−1) and detectivity (D*) (2.1 × 1011 Jones) than the original device, which are improved by 22 times, 6 times and 10 times @ 660 nm, respectively. This work can enlighten the synthesis and application of low temperature ZnO thin film that can be applied for high performance Sb2Se3 PDs and other optoelectronic devices with heat-labile materials.

Nano MgCuAl2O5: Synthesis by Sol-Gel Auto-Combustion Process, Characterization and Reusable Heterogeneous Catalyst for the Hantzsch 1,4-Dihydropyridine Reaction

For the first time, MgCuAl2O5 heterogeneous nanocatalysts were prepared by sol-gel auto-combustion method, which displayed great yield and suitable activity for the preparation of 1,4-DHP derivatives with high efficiency in green solvent ethanol/water (1:1) at 80 °C under one pot condition. The synthesis materials were separated in short reaction times with excellent yield (80–95) %. Moreover, the synthesized nanocatalyst was easily retrieved and continuously reused for six reactions without a noticeable significant loss of proficiency. The solid catalyst was confirmed by XRD, BET, FTIR, FESEM and EDX, and the substituted 1,4-dihydropyridines were characterized by melting point, 1H and 13C NMR.