Crystallite Size Research Articles

Efficient removal of basic yellow 28 dye from water using facilely synthesized ZnO and Mg3B2O6 nanostructures

Basic yellow 28 dye, used extensively in the textile and leather industries, poses significant environmental and health risks, including allergic reactions, skin irritation, and respiratory problems. This study reports the Pechini sol-gel synthesis of novel ZnO/Mg3B2O6 nanostructures for the decontamination of basic yellow 28 dye from aqueous solutions. The nanostructures were synthesized by calcining at 650 and 850 °C for 5 h, producing ZM650 and ZM850, respectively. The average crystallite sizes were 39.28 nm for ZM650 and 51.03 nm for ZM850. BET surface areas were 70.71 m2/g for ZM650 and 48.13 m2/g for ZM850. FE-SEM and HR-TEM analyses revealed distinct morphological structures, with ZM650 exhibiting a dense aggregation of rod-like particles and ZM850 showing larger clusters. The maximum adsorption capacities were 381.68 mg/g for ZM650 and 303.03 mg/g for ZM850. The optimum adsorption was observed at a pH of 10, a contact time of 70 min, and a temperature of 298 K. Regeneration using a 6 M HCl solution demonstrated efficient reusability over five cycles. The adsorption process followed pseudo-second-order kinetics and the Langmuir isotherm, indicating monolayer adsorption. Also, the adsorption process was found to be physical and exothermic.

Antibacterial and Methylene Blue Dye Degradation Activity of hibiscus rosa sinensis Synthesized CoFe2O4 Nanocomposites

AbstractCo‐precipitated biotic CoFe2O4 nanoparticles from the leaves of the Hibiscus rosa sinensis plant were used to produce bio‐reductant nanoparticles. The CoFe2O4 biomolecules were analyzed using EDX analysis to identify their structure through XRD, FTIR, UV, VSM, and SEM characterization. The cubic phase and crystallite size of biotic CoFe2O4 nanoparticles were determined using XRD analysis. The FTIR spectroscopy was used to confirm Cation migration and Co−Fe−O interaction. Using SEM, TEM, and EDX, it was confirmed that spherical biosynthesized CoFe2O4 nanoparticles and the material they were made were present. VSM analysis confirmed the super‐paramagnetic nature of the CoFe2O4 nanoparticles and magnetic pulse. Biosynthetic CoFe2O4 nanoparticles were used to eliminate organic(MB dye) and bacterial(S. aureus, B.Substils, and E. coli bacterial strains) pollutants. Spinel ferrite biosynthetic CoFe2O4 nanoparticles are capable of generating radical superoxide ions.

Study of Structural, Thermal and Electrical Properties of Sr-Doped CaMnO<sub>3</sub>

Sr-doped CaMnO3 materials have wide applications due to their thermal and electrical properties. The importance of the synthesis of Sr-doped CaMnO3 material for various applications encourages researchers to evaluate and refine the synthesis process. In this study, Ca1-xSrxMnO3 (x = 0; 0.05; 0.1; 0.15; 0.2) system has been prepared by sol-gel method followed by conventional sintering process at 850°C for 8 hr. A thorough discussion has been made on the outcomes derived from the investigation on the structural, electrical, and thermal properties of Sr-doped CaMnO3 system using powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, DC fourprobe method, thermal expansion studies, and thermoelectric power analyses. The XRD patterns of all prepared samples exhibited single phase with orthorhombic crystal structure (space group Pnma). Rietveld refinements were performed for all the patterns by using Fullprof software to extract the structural properties. The values of unit cell volume of samples tend to increase with the increment of dopant concentration, whereas the crystallite size values were decreased with dopant concentration. The microstructures of all the samples were studied using SEM, and elemental compositions were confirmed from the EDS results. Linear thermal expansion coefficients of all the samples were found to have moderate values in the temperature range from 30°C to 800°C. The electrical properties of all the system of samples were studied in the temperature range from 30°C to 400°C using DC fourprobe conductivity setup. It was found that all the samples exhibited semiconductor nature. Sr-content on the A-site suppress the electrical resistivity up to 10% of concentration and 5% dopant content exhibited the lowest electrical resistivity. The values of Seebeck coefficient found to vary from -160 µV/K to -124 µV/K with the increase of dopant content in the parent compound.

One-Pot Synthesis and Characterization of Magnetic α-Fe2O3/CuO/CuFe2O4 Nanocomposite for Multifunctional Therapeutic Applications.

This study demonstrates a novel nanostructured drug delivery system utilizing α-Fe2O3/CuO/CuFe2O4 ternary nanocomposite for effective drug transport in sick tissues. Centella Asiatica plant extract was employed to synthesize the Fe2O3/CuO/CuFe2O4 nanocomposite via sol-gel auto combustion technique. The structural and morphological characteristics of the nanocomposite were investigated by XRD, FT-IR, SEM, EDX, and VSM for magnetic properties. The XRD analysis demonstrates the successful synthesis of Fe2O3/CuO/CuFe2O4 nanocomposite with an average crystallite size of 18.393 nm. The antioxidant and antifungal capabilities of this nanocomposite were assessed for its biological activity. A notable inhibitory zone was observed when tested against the Alternaria spp. and Bipolaris sorokiniana fungi. An IC50 value of 109.88 μg/ml was found in the DPPH test, indicating that the nanocomposite exhibited remarkable antioxidant characteristics. Subsequently, metronidazole was encapsulated with a success rate of 55.53 % at pH 1.2, while at pH 7.4 it gained 57.83 %. The drug release of nanocomposite at pH 1.2 after 330 min was 43.41 % and at pH 7.4 after 300 min it was 52.3 %. The results indicate its potential as an excellent candidate for drug delivery. Furthermore, pH was found to be an effective catalyst in the drug loading and release processes.

Effect of Gd doping on the microstructure and electrical characteristics of Maghemite (γ-Fe₂O₃) ceramics

AbstractThis paper presents a novel study on the microstructure and electrical properties of gadolinium (Gd) doped maghemite (γ-Fe₂O₃) nanoparticles, emphasizing their significance for advanced applications in efficient materials. X-ray diffraction analysis confirmed that both pure and doped samples crystallized in a cubic structure (P4332 space group) with high purity. Gd doping significantly increased crystallite size and altered particle morphology, as shown by transmission electron microscopy (TEM), which revealed larger nanoparticles with cubic shapes. Thermal analysis (TGA and DTG) indicated that higher Gd concentrations enhanced thermal instability, affecting structural integrity. FTIR spectra showed shifts in Fe-O bond vibrations, suggesting lattice distortions and increased disorder. BET measurements indicated that higher Gd doping led to greater mesoporosity and surface area, countering expectations of densification. Electrical conductivity and impedance studies revealed two distinct regions: a constant conductivity at low frequencies and an exponential increase at high frequencies, attributed to small polaron hopping. Activation energy values below 200 meV support this mechanism. Gd doping decreased overall conductivity due to disrupted atomic arrangements, increased electron scattering, and modifications in the electronic band structure. Complex impedance spectroscopy illustrated higher real impedance values for doped samples, with increased Gd concentration leading to enhanced impedance. These findings elucidate the impact of Gd on the electrical properties of maghemite nanoparticles and highlight their importance in meeting the growing demands for highly efficient technologies in energy storage and electronic devices. Graphical Abstract

Nanostructured spinel ferrites: A comprehensive study on the synthesis, characterization, and magnetic properties of Zn and Mn substituted magnetite nanoparticles produced through the co-precipitation method

Seven cubic spinel ferrite nanoparticles were successfully synthesized through the co-precipitation method. These nanoparticles include Fe3O4, Zn0.4Fe0.62+Fe23+O4, Mn0.4Fe0.62+Fe23+O4, Zn0.6Mn0.4Fe0.42+Fe1.63+O4, Zn0.4Mn0.6Fe0.42+Fe1.63+O4, Zn0.4Mn0.4Fe0.22+Fe23+O4, and Zn0.4Mn0.4Fe0.42+Fe1.83+O4. The Rietveld method was used to analyze X-ray diffraction data, confirming that all samples have a single-phase cubic spinel structure. The presence of zinc and manganese ions in magnetite lattice leads to changes in lattice parameters and crystallite size, resulting in a range of 7–12 nm crystallite sizes. Fourier transform infrared spectroscopy (FT-IR) analysis of nanoparticles reveals two significant adsorption peaks at 560-576 cm−1 and 437-449 cm−1, corresponding to metal ion stretching vibrations at tetrahedral and octahedral sites. The X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of iron, zinc, and manganese in various oxidation states. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) images showed spherical, agglomerated nanoparticles. The study confirmed the elemental composition and mapping images of prepared samples using energy-dispersive X-ray spectroscopy (EDS). The magnetic properties of the synthesized nanoparticles were meticulously examined utilizing a vibrating sample magnetometer (VSM) at room temperature. A direct correlation is established between the structural alterations induced by Zn2+/Mn2+ and their subsequent effects on magnetic characteristics, specifically through the reallocation of cations and the mechanisms of electron hopping occurring at the B-sites. The structural modifications result in enhanced superparamagnetic behavior, exhibiting saturation magnetization values between 46.01 and 69.38 emu/g. The sustainable characteristics of these materials render them highly viable options for applications in environmental remediation and green technology.

Enhanced Impact Resistance, Oxygen Barrier, and Thermal Dimensional Stability of Biaxially Processed Miscible Poly(Lactic Acid)/Poly(Butylene Succinate) Thin Films

This study investigates the crystallization, microstructure, and performance of poly(lactic acid)/poly(butylene succinate) (PLA/PBS) thin films processed through blown film extrusion and biaxial orientation (BO) at various blend ratios. Succinic anhydride (SA) was used to enhance interfacial adhesion in PLA-rich blends, while blends near 50/50 formed co-continuous phases without SA. Biaxial stretching and annealing, adjusted according to the crystallization behavior of PLA and PBS, significantly influenced crystallinity, crystallite size, and molecular orientation. Biaxial stretching induced crystallization and ordered chain alignment, particularly at the cold crystallization temperature (Tcc), leading to a 70–80-fold increase in impact resistance compared to blown films. Annealing further enhanced crystallinity, especially at the Tcc of PLA, resulting in larger crystallite sizes. BO films demonstrated reduced thermal shrinkage due to improved PLA crystalline structure, whereas PLA-rich blown films showed higher shrinkage due to PLA’s lower thermal resistance. The SA-miscibilized phase reduced oxygen transmission in blown films, while BO films exhibited higher permeability due to anisotropic crystal orientation. However, the annealing of BO films, especially at high temperature (Tcc of PLA), further lowered oxygen permeability by promoting the crystallization of both PLA and PBS phases. Overall, the combination of SA compatibilization, biaxial stretching, and annealing resulted in substantial improvements in mechanical strength, dimensional stability, and oxygen barrier properties, highlighting the potential of these films for packaging applications.

Development of graphitic and non-graphitic carbons using different grade biopitch sources

The growing demand for bio-renewable alternatives to fossil fuels in the production of sustainable carbon materials, aimed at reducing environmental impact, is crucial for advancing a greener future. This research explores an innovative approach for producing biopitches from bio-oils, which are subsequently utilized as a sustainable precursor for developing advanced graphitic carbons (GC) and non-graphitic carbons (NGC) through carbonization and graphitization processes. The study emphasizes the impact of the chemical composition of bio-oils and biopitches, including heteroatom structures, aromatic/aliphatic ratio, and oxygen content with oxygen-bearing functional groups, on the production of GC and NGC. The research also examines their structural parameters at various heating temperatures using characterization techniques such as X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. XRD analysis revealed that GC samples have lower interplanar spacing (d002) and larger crystallite size than NGC, while Raman shows more short-range order and defects in NGC. Furthermore, HRTEM images and fringe analysis demonstrated differences in lamellae structures, tortuosity, and fringe length. These observations, unveiling differences in crystallite size and degree of graphitization between GC and NGC, underscore the influence of temperature on structural order and defect annealing, which is crucial for optimizing material properties.

Synthesis of MgO nanoparticles via the sol-gel method for antibacterial applications, investigation of optical properties and comparison with commercial MgO

Magnesium oxide nanoparticles (MgO-NPs) were synthesized using the solution-gelation (sol-gel) technique. For comparison, US Research Nanomaterials, Inc has supplied MgO with very high purity and used without further purification. Both nanoparticles were subjected to X-ray diffraction (XRD) pattern analysis for structural investigation. The XRD measurements showed an incredibly crystalline cubic structure. Morphological studies were carried out using scanning electron microscopy (SEM) measurements to examine the nanoparticles’ size and shape. SEM analysis of the synthesized sample’s morphology revealed a flake-like shape, while a spherical-like structure was observed in the case of the commercial MgO. Using X-ray peak broadening analysis, the Scherrer method was used to assess the crystallite size. A substantial correlation was found between the Scherrer formula and the average particle size of the MgO-NPs, which was determined through SEM analysis. The energy gap calculations were ascertained by plotting the photon energy utilizing the Tauc equation with the measurements of UV–visible absorption spectroscopy. Both nanoparticles were used against the bacterial activity of Streptococcus and Serratia bacteria. The results showed that synthesized nanoparticles exhibited greater effectiveness against bacterial activity than commercial ones.

Anticancer Activity of Green Synthesized Manganese Doped Cerium Oxide Nanoparticles Prepared by Using Acacia Concinna Fruit Extract

AbstractPure CeO2 and Ce1‐xMnxO2, where x = 0, 2, 4 and 6% w/w, were synthesized by sol‐gel method using Acacia Concinna fruit extract as a surfactant and stabilizing agent. The synthesized particles were subjected to various characterization techniques, including XRD, HRTEM, FESEM, FTIR, Raman and UV‐Visible spectroscopy. The XRD pattern of the samples demonstrated single phase of CeO2, with cubic fluorite type structure and crystallite size of 6–7 nm. The morphology of the nanoparticles (NPs) was analyzed by FESEM and HRTEM which illustrated an aggregate of irregular spherical nanoparticles and the average particle size is around 18 nm. Raman spectroscopy validated the phase purity and indicated about the structural defects caused by the dopants. The bandgap energy of CeO2 NPs is calculated to be 3.00 eV from the Tauc plot of UV‐Visible spectroscopy, which gradually decreased to 2.43 eV with increase in manganese doping. Cytotoxicity studies signified the role of Mn‐doped CeO2 NPs as a potential nanotherapeutic agent for cancer treatment. The cell viability assay showed that 200 µg/mL of 6% Mn‐doped CeO2 nanoparticles exhibited remarkable cytotoxic effect by inhibiting 50% of cancer cells both in breast and colon cancer cell lines without affecting the healthy cell lines.

Optimisation, Synthesis, and Characterisation of ZnO Nanoparticles Using Leonotis ocymifolia (L. ocymifolia) Leaf Extracts for Antibacterial and Photodegradation Applications

This work presents a green synthesis route, which utilises extracts from an indigenous plant in South Africa, eastern and southern Africa that is understudied and underutilised, for preparing zinc oxide nanoparticles (ZnO NPs). This study involved optimisation of the green synthesis method using Leonotis ocymifolia (L.O.) extracts and performing comparative studies on the effects of using different zinc (Zn) salt precursors; zinc sulphate heptahydrate (Z001) and zinc acetate dihydrate (Z002) to synthesise the ZnO NPs. The comparative studies also compared the L.O-mediated ZnO NPs and chemical-mediated ZnO NPs (Z003). The as-prepared ZnO NPs were tested for their effectiveness in the photodegradation of methylene blue (MB) dye. Furthermore, antibacterial studies were conducted using the agar well diffusion method on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. The structural, morphological, and optical characteristics of the synthesised ZnO NPs were analysed using XRD, FTIR, SEM, EDS, DRS, and BET techniques. The XRD results indicated that the L.O-mediated ZnO NPs had smaller crystallite sizes (18.24–19.32 nm) than their chemically synthesised counterparts (21.50 nm). FTIR confirmed the presence of biomolecules on the surface of the L.O-mediated NPs, and DRS analysis revealed bandgap energies between 3.07 and 3.18 eV. The EDS results confirmed the chemical composition of the synthesised ZnO NPs, which were made up of Zn and O atoms. Photocatalytic studies demonstrated that the L.O-mediated ZnO NPs (Z001) exhibited a superior degradation efficiency of the MB dye (89.81%) compared to chemically synthesised ZnO NPs (56.13%) under ultraviolet (UV) light for 240 min. Antibacterial tests showed that L.O-mediated ZnO NPs were more effective against S. aureus than E. coli. The enhanced photocatalytic and antibacterial properties of L.O-mediated ZnO NPs highlight their potential for environmental remediation and antimicrobial applications, thus supporting sustainable development goals.

Spectroscopic properties of red-emitting Sr0.9Na0.2ZrO3:Eu3+ phosphors with potential applications in lasers and LEDs

A range of Sr0.9-yNa0.2ZrO3: Eu3+ (SNEZ) nanocrystalline phosphors with high color purity and exceptional laser properties were synthesized using sol-gel technique. The samples were characterized for structural and spectroscopic properties using methods including X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), diffuse reflectance spectroscopy, and photoluminescence (PL) spectroscopy. Structural analysis revealed orthorhombic phase with average crystallite size 28-19 nm, decreasing with increasing Eu3+ concentration. A low phonon energy of 455–495 cm−1 and wide (expanding) band gaps (5.0–5.3 eV) were obtained for the SNEZ phosphors. Under the excitation of 300 nm, the SNEZ phosphor emits strong red light at 614 nm, attributed to the 5D0 → 7F2 transition of the Eu3+ ion. Both XRD and Judd-Ofelt analysis revealed two sites for the Eu3+ ions. Additionally, the optimized SNEZ-7 phosphor achieves a PL internal quantum efficiency of 96 % under UV light at 300 nm excitation. Laser properties such as stimulated emission cross-section, gain bandwidth, branching ratio of the SNEZ phosphor is comparable to those of glasses, fluorides and other oxides for red light emitting laser applications. The CIE coordinate values of the synthesized red phosphor closely match those of commercially available red light-emitting phosphors, with a purity level of about 95 %. This suggests its suitability for various device applications, particularly in high-power white LEDs and lasers, as a red emitter.

Investigation of the Effects of Cu and Fe/Cu Doping on ZnO Nanoparticles for Application as a Solid Electrolyte Battery

In this work, investigation is done on the effect of doping with copper (Cu) and iron/copper (Fe/Cu) on zinc oxide (ZnO) nanomaterials synthesized through a cost‐effective wet chemical precipitation method for application as a solid‐state electrolyte battery. The scanning electron microscope with energy dispersive X‐ray spectroscopy is used to investigate the morphology and elements presence in Cu and Fe/Cu‐doped ZnO nanoparticles. The X‐ray diffraction data illustrates that the crystallite sizes of pure ZnO, Cu–ZnO, and Fe/Cu–ZnO nanoparticles are 14.86, 13.35, and 10.66 nm, respectively, at the (101) plan calculated by Debye Scherrer's formula. The UV‐Vis absorption spectrum shows that the band gap energies of ZnO, Cu–ZnO, Fe–ZnO, and Fe/Cu–ZnO nanoparticles are identified as 3.382, 3.690, 3.5, and 3.465 eV, respectively. The electrical characterization revealed maximum impedance in Fe/Cu–ZnO nanoparticles with 400 Ω at 1 KHz frequency in comparison to other samples. The current–voltage (I–V) measurement shows that the current sensitivity and electrical conductivity are both enhanced for Fe/Cu–ZnO nanoparticles. Fe and Cu co‐doping improved the electrical characteristics of ZnO, and the Fe/Cu–ZnO nanoparticles are employed as a solid electrolyte in a battery, which achieved a high specific charge capacity of 657.85 mAh g−1.

Enhancing shielding efficiency of ordinary and barite concrete in radiation shielding utilizations

Concrete has been widely utilized as a radiation shielding material due to its properties and structural integrity. This study aims to evaluate the efficiency of ordinary concrete versus barite concrete as radiation shielding materials, focusing on the physical aspects and changes in crystal size lattice parameters after neutron irradiation. Specifically, the research investigates the shielding effectiveness of these materials across different grades (M15, M25, M35, and M45) against gamma-ray sources Cobalt-60 and Caesium-137. The methodology involves measuring the linear attenuation coefficient (μ), half value layer (HVL), tenth value layer (TVL), and mean free path (MFP). Additionally, X-ray diffraction (XRD) was employed to assess crystallite size and lattice parameter changes post-irradiation for neutron irradiation. Results indicate that incorporating barite as an aggregate significantly enhances the density and crystallite macroscopic properties of the concrete. Irradiation with Cobalt-60 and Cesium 137 revealed that ordinary concrete has a lower linear attenuation (μ) ranging from 0.172 to 0.195 cm−1, with consistent mass attenuation across all grades at 0.81 cm2/g. XRD analysis demonstrated a rightward shift in the SiO₂ and BaSO₄ peaks post-irradiation, signifying crystalline expansion. In terms of lattice parameters, the d-value showed a notable decrease of 0.10 after 48 h of irradiation in grade 25, while the most significant increase of 0.02 occurred after 24 h of irradiation in grades 15 and 45. In conclusion, barite concrete proves to be more effective for radiation shielding in nuclear facilities, whereas ordinary concrete is suitable for medical shielding, or facilities exposed to lower radiation doses.

Crystallite size and phase purity in Pb1-xSrxTiO3 ferroelectric perovskites for biomedical applications via controlled sintering

ABSTRACT Lead strontium titanate (Pb1-xSrx)TiO3 (PST) is a ferroelectric perovskite material with tunable properties, including Curie temperature, spontaneous polarization, and high dielectric permittivity, making it promising for advanced biomedical applications, such as biosensors, bioimaging, and light-activated therapeutics. This study investigates the effect of varying sintering temperatures on the crystallite size and phase purity of PST, aiming to optimize its performance for biomedical devices. PbCO3, SrCO3, and TiO2 powders were processed via ball milling for 58 hours, followed by sintering at temperatures ranging from 500°C to 1100°C. Laser diffraction particle size analysis and X-ray diffraction (XRD) were used to assess the particle size and crystal phase transformations. The results demonstrate that higher sintering temperatures improve the PST phase composition, reducing impurities and enhancing crystallite growth. The most significant crystal growth was observed at 900°C, while the optimal phase purity and crystallite size (91.5 nm) were achieved at 1100°C, producing 100% single-phase PST. These findings emphasize the critical role of sintering temperature in tailoring PST’s properties, enhancing its suitability for electronic and microelectronic biomedical devices. Controlled sintering in perovskite materials opens new pathways for their application in medical diagnostics and therapeutic technologies.

Probing structural and electrochemical properties of a 2D CoMoO4@hBN nanocomposite as pseudocapacitive electrode for high-performance supercapacitors

The effectiveness of energy storage is largely determined by the electrode material's performance in critical areas. Enhancements in ion transport, cyclic stability, rate capability, and specific capacitance directly boost the supercapacitors' overall performance and broaden their application potential. This study aims to enhance these properties by incorporating hexagonal boron nitride (hBN) into cobalt molybdate (CoMoO4) material in a 1:1 stoichiometric ratio. The CoMoO₄@hBN nanocomposite was synthesized using a hydrothermal method followed by ball milling. The X-ray diffraction (XRD) analysis confirmed the formation of a single-phase CoMoO4@hBN composite, with a significant increase in crystallite size from 18.21 nm in pure CoMoO₄ to 25.6 nm, along with a slight shift in diffraction peaks, indicating enhanced crystallinity and structural defects due to the substitution of oxygen with boron atoms. Raman spectroscopy revealed that the composite retains the characteristic peaks of both CoMoO₄ and hBN, with stable sharp peaks at 936 cm−1 (Mo=O bond) and 1367 cm−1 (E2g peak of hBN) even after 20 depth measurements, confirming successful conjugation and consistent vibrational properties. The X-ray photoelectron spectroscopy (XPS) showed a slight shift in Co 2p and Mo 3d binding energies to higher values, suggesting improved electronic interactions between CoMoO4 and hBN, which could enhance the composite's conductivity. The electrochemical analysis demonstrated that incorporating h-BN significantly boosts the electrode's performance compared to pristine CoMoO4, with about 37 % increase in specific capacitance at 1 A g−1, reduced charge transfer resistance (0.11 Ω), and superior cyclic stability with 96 % capacitance retention after 5000 cycles. These findings indicate that hBN enhances both the electrical conductivity and structural integrity of CoMoO4, positioning the CoMoO4@hBN composite as a promising material for high-performance supercapacitors.

Influence of transition metal (Cu) and rare earth metal (Dy) co-doping on spinel zinc ferrite (Cu0.1Dy0.08Zn0.9Fe1.92O4) for improved photocatalytic degradation of industrial effluents

In the present era, design and development of novel, highly stable, easily and magnetically separable, cost effective, and visible light driven catalytic material for the removal of harmful industrial effluents is of great importance. In this context, facile co-precipitation route was adopted for the synthesis of ZnFe2O4 (ZFO), Cu0.1Zn0.9Fe2O4 (CZFO), Dy0.08ZnFe1.92O4 (DZFO), and Cu0.1Dy0.08Zn0.9Fe1.92O4 (CDZFO) and their fabrication was confirmed by XRD, FTIR, SEM, and UV-Visible spectroscopy. The phase analysis of all designed materials exhibits that there is an increment in the crystallite size of co-doped zinc ferrite (CDZFO) i.e. 11.51 nm as compared to ZFO (10.74 nm), CZFO (10.92 nm), and DZFO (11.41 nm). The optical study shows a significant decrease in bandgap of CDZFO i.e. 1.82 eV as compared to DZFO (1.89 eV), CZFO (2.0 eV), and ZFO (2.14 eV). This decrease in optical bandgap and increase in crystallite size of the CDZFO is due to the quantum confinement effect. The photocatalytic efficiency of pure, doped, and co-doped samples was investigated against organic dye (Congo red), pharmaceutical drug (ibuprofen), and colorless organic compound (benzoic acid). The photocatalytic results reveal that CDZFO showed about ∼90 % degradation of Congo red while ZFO, CZFO, and DZFO showed only 59 %, 70 %, and 79 % respectively. Moreover, CDZFO also showed highest photocatalytic removal efficiency against ibuprofen (88 %) and benzoic acid (74 %) out of all other synthesized materials. The remarkable photodegradation ability of CDZFO for all targeted pollutants could be attributed to the generation of crystal defects in its lattice, its small bandgap, and higher absorption in visible region. Furthermore, the recyclability experiment confirmed the stability and reusability of the prepared sample.

Improving the Nonvolatile Memory Characteristics of Sol–Gel-Processed Y2O3 RRAM Devices Using Mono-Ethanolamine Additives

In this study, Y2O3-based resistive random-access memory (RRAM) devices with a mono-ethanolamine (MEA) stabilizer fabricated using the sol–gel process on indium tin oxide/glass substrates were investigated. The effects of MEA content on the structural, optical, chemical, and electrical characteristics were determined. As the MEA content increased, film thickness and crystallite size decreased. In particular, the increase in MEA content slightly decreased the oxygen vacancy concentration. The decreased film thickness decreased the physical distance for conductive filament formation, generating a strong electric field. However, owing to the lowest oxygen vacancy concentration, a large electrical field is required. To ensure data reliability, the endurance cycles across several devices were measured and presented statistically. Additionally, endurance performance improved with the increase in MEA content. Reduced oxygen vacancy concentration can successfully suppress the excess formation of the Ag conductive filament. This simplifies the transition from the high- to the low-resistance state and vice versa, thereby improving the endurance cycles of the RRAM devices.

Concurrent conversion of waste cooking oil using Al metal-organic framework and subcritical methanol through esterification/transesterification process

Recently, some scientists have focused on discovering techniques for manufacturing biodiesel on a significant, efficient, and ecologically sustainable scale. Choosing a catalyst is a notable challenge due to the instability and cost feasibility issues connected with newly designed homogeneous and heterogeneous catalysts. This paper describes the synthesis and utilization of aluminum-based metal-organic frameworks (MOFs) as catalysts for the generation of biodiesel from waste cooking oil (WCO). The processes involved in this study are esterification and transesterification, which are carried out using subcritical methanol. The catalyst analysis reveals that the MOFs possess a filamentous structure, with a crystallite size ranging from 300 to 500 nm. Furthermore, these MOFs exhibit thermal stability up to 470 °C. The catalyst underwent examination for biodiesel production from waste cooking oil (WCO), and the resulting biodiesel samples met the standards set by the American Society for Testing and Materials (ASTM). The experiment was devised and fine-tuned to incorporate the three independent variables using a multilevel factorial design, response surface methodology, and a three-way analysis of variance (ANOVA). The FAME conversion peaked at 91.96 %, as determined through statistical analysis of the optimization findings. The corresponding values for the variables were X1: 423.15 K, X2: 1800s, and X3: 28 mol/mol. Based on ANOVA statistics, the experimental and mathematical verification demonstrates a fair correlation between the actual and calculated catalyst performance. The temperature and molar ratio of methanol: WCO significantly affected the FAME conversion.

Unravelling the effect of crystal lattice compression on the supercapacitive performance of hydrothermally grown nanostructured hollandite α-MnO2 induced by incremental growth time

Manganese oxide (α-MnO2) nanoparticles are highly recognised for their use in supercapacitor applications. This study demonstrates the successful synthesis of flower-like and nanorods hollandite α-MnO2 by a simple one-pot hydrothermal technique at various reaction times. The synthesised nanoparticles were characterised by various physicochemical and electrochemical characterisation techniques. The influence of the various reaction times on the structural and morphological properties was evaluated by X-ray diffraction (XRD) and scanning electron microscope. XRD patterns revealed that the synthesized MnO2 nanoparticles are tetragonal structures with crystallite sizes ranging from 13.69 to 20.37 nm estimated from the Williamson–Hall method. Moreover, the functional groups and surface area were examined by Fourier transform infrared spectroscopy and Bruner–Emmert–Teller, respectively. Furthermore, the compositional elements were studied by X-ray photoemission spectroscopy and energy-dispersive X-ray spectroscopy. Finally, the electrochemical performances were studied using cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS). The GCD characteristics revealed that the optimised α-MnO2 has a good capacitive behaviour, which predicts the potential application in energy storage. Electrochemical studies revealed that the 3 h-MnO2 sample exhibited a superior electrochemical behaviour and demonstrated a high specific capacitance of 132 F/g at a current density of 1A/g.