Sol-gel Method Research Articles

Structural and optical characteristics of Cr-doped TiO2 thin films synthesized by sol-gel method

In this paper, undoped and 7 %, and 20 % chromium doped titanium dioxide thin films were synthesized on silicon and quartz substrates by utilizing the sol-gel spin coating process. The films were then annealed at 450 °C. The synthesis process and the effects of doping on the structural, optical, and vibrational properties were studied. XRD analysis showed that the undoped thin film had an anatase phase with a crystalline size of about 15.4 nm. However, as the concentration of chromium increased, the crystalline size decreased, and we obtained a mixed phase of rutile and anatase for doped films. The FTIR spectra revealed that undoped films had Ti–O bonding at 435 cm−1 and bond with stretching at 619 cm−1 wavenumbers, which decreased to 379 cm−1 and 377 cm−1 wavenumbers for 7 % and 20 % Cr doping, respectively. The optical measurements showed that the films were homogeneous and had high transmission, reaching 95 % in the visible range for the undoped thin film and 80 % for higher doping levels of chromium. These films have a remarkable level of transparency, and because of that they are highly regarded in the field of thin-film solar cells. Their optical properties make them an excellent choice for use as optical windows in these types of solar cells. As the amount of chromium in the film increases, the optical bandgap decreases from 3.23 eV to 2.26 eV. This suggests that chromium has a significant impact on the optical properties of these films, which might be helpful to researchers and professionals working in the fields of solar energy, optoelectronic devices, photocatalytic systems, gas sensors, and solar cell passivation.

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.

Preparation and patterning of HfO2 film via sol–gel method and resistive switching effect of Pt/HfO2/LaNiO3

Sol–gel method is a low-cost material preparation method; however, it is difficult to obtain a stable sol containing easily hydrolyzable metal ions via this method. In this study, a stable hafnium(IV) oxide (HfO2) sol was prepared by adding benzoyl acetone (BzAcH) modifier. Infrared absorption spectroscopy results showed that the BzAcH additive chelated with the Hf4+ ions in the sol, thus improving the hydrolysis resistance of the HfO2 sol, which in turn improved its stability. It was also found that the BzAcH-modified HfO2 gel film exhibited ultraviolet (UV) photosensitivity. After UV exposure, the film did not dissolve easily in organic solvents. Based on these properties, the micro processing of the HfO2 film was preliminarily explored, and HfO2 microstructures were successfully obtained. Additionally, the relative permittivity (εr) of HfO2 exhibited minimum (∼10.9) and maximum (∼20.6) values at heat-treatment (HT) temperatures of 350 and 450 °C, respectively. With the continuous increase in the HT temperature, εr first decreased and then increased slightly. Moreover, the current–voltage curves showed that the Pt/HfO2/LaNiO3 (LNO) structure exhibited a pronounced bipolar resistive switching (RS) effect, which was attributed to the fact that LNO could be used as an electrode and an oxygen vacancy (OV2+) storage layer for RS materials. Notably, the oxygen ions in HfO2 with a low degree of crystallinity are more likely to migrate within its body (which makes it easier to form OV2+s), therefore, the “Set” voltage of low-crystallinity HfO2 films is lower than that of high-crystallinity HfO2 films. The RS mechanism can be explained by the OV2+ conductive filament model. These results are of great practical significance for the low-cost preparation of HfO2 and the application of LNO as an oxide electrode.

Co-hydrolysis of TEOS and DDS to obtain a modified hydrophobic SiO2 insulation layer for FeSiBC amorphous magnetic powder core with low energy loss

The hysteresis effect and eddy currents caused by alternating magnetic fields greatly impede the improvement of the working efficiency and performance stability of soft magnetic powder cores. In this work, modified hydrophobic SiO2 nanoparticles were prepared by tetraethyl orthosilicate (TEOS) and dimethyl-diethoxy-silane (DDS) as co-precursors through sol–gel methods. The effect of different proportions of DDS and TEOS on the amorphous magnetic powder cores performance was studied. It was demonstrated that the insulation layer in DDS and TEOS co-precursors hydrolyzed composite powders exhibited more uniform distribution compared with TEOS hydrolyzed alone counterpart. The introduction of methyl groups reduced the accumulation of hydrolysis intermediates on the surface of FeSiBC powders. Furthermore, the addition of DDS reduced eddy current loss significantly with a low hysteresis loss. The total energy loss of the DDS and TEOS co-hydrolysis powder core were reduced by 16.1 % and 7.7 % at 1 MHz, 0.05 T compared to the uncoated powder core and the TEOS hydrolysis alone counterpart, respectively. The presented results provide insights into improving the application range and energy utilization efficiency for the magnetic powder cores.

Enhance the loss of sound transmission of glass using a thin polyester/silica aerogel composite as a new sound insulation

One of the problems of the glass is the noise pollution that is easily directed into the building. Using a very thin and cheap layer on the glass can effectively prevent the transmission of sound, reduce costs, and increase the peace of its residents. In this work, two types of silica aerogel (SA) were synthesized by using sodium silicate as a precursor in the sol-gel method in the presence (SA-U) and absence of ultrasound (SA-C). The synthesized SA samples were converted into discs under 100 bar pressure and investigated their sound transmission loss (STL). The average STL of SA-U sample was 32 dB, while it was 21 dB for SA-C. The synthesized SA samples in the presence and absence of ultrasound were added to polyester (PES) resin and prepared SA-U/PES and SA-C/PES composites. The prepared composites were deposited with a thickness of 1 mm on a glass with a thickness of 3 mm. The SA-C/PES composite was able to improve the STL of glass to 28.5 dB, while the SA-U/PES composite was able to improve it to 27.3 dB. The average STL of the glass was only 11.2 dB.

Optimizing optical thermometry with tri-doped Ba2GdV3O11 phosphors: Ratiometric and fluorescence lifetime analysis

Optical sensor technology has undergone a transformative evolution with the advent of fluorescence ratio techniques (FIR) and fluorescence lifetime (FL) strategies, revolutionizing precision, performance, and reliability. This study delves into the synthesis of Ba2GdV3O11 phosphors doped with Ho3+/Nd3+, Er3+, and Yb3+, employing the sol-gel method for upconverting material fabrication. A thorough investigation into the structural, morphological, and optical properties of the synthesized phosphors is conducted. Excitation at 980 nm unveils upconversion (UC) emissions across green and red spectra. The intensities of the observed emission bands for Ho3+, Nd3+, and Er3+ demonstrate significant sensitivity to fluctuations in temperature. Temperature sensing relies on the 4S3/2 and 2H11/2 upconversion emissions bands, in addition to the emission lifetimes at 4S3/2. Enhanced thermal sensitivity values are attained, reaching up to 1.03 % K−1 and 1.07 % K−1 using the FIR strategy, and up to 0.146 % K−1 and 0.47 % K−1 with the FL strategy for Ho3+/Er3+/Yb3+ and Nd3+/Er3+/Yb3+ tri-doped Ba2GdV3O11 phosphors, respectively. Furthermore, the studied phosphors exhibit remarkable precision in detecting minute temperature changes (0.3 K), positioning them as promising candidates for precise temperature sensing. This study pioneers innovative methodologies to advance optical thermometry techniques, offering promising prospects for scientific and industrial applications reliant on precise optical temperature sensing.

Carbamide-mediated facile sol-gel synthesis of porous flower-like ZnCo2O4 microspheres for high-performance asymmetric coin cell supercapacitors

The design and development of ultrahigh-performance nanomaterials possessing novel characteristics are needed to achieve reliable energy storage performance. To satisfy the needs, diverse electrode materials are explored. Even though carbon-based materials hold high surface area and conductivity, their specific capacitance value fails to deliver high-performance applications. Therefore, pseudocapacitive transition metal oxide is adopted to overcome these issues. Among all Zinc Cobaltite, a binary transition metal oxide is widely explored owing to its fascinating electrochemical properties. As most of the synthesis of these kinds of materials requires the hydro/solvothermal method, herein, we have proposed the concept of a facile sol-gel method to prepare this class of materials by using Carbamide as both structure director and fuel to achieve the porous flower-like Zinc Cobaltite. The prepared material delivers the notable gravimetric specific capacitance of 513.3 F g−1. Owing to its unique morphology and porous structure, ion channelization is feasible, which will enhance the electrochemical reaction. Constructed asymmetric coin cell supercapacitor showed an extraordinary specific capacitance of 106.5 F g−1 and energy density of 56.2 Wh kg−1, demonstrating an impressive ability to retain 89.6 % of its capacitance after 4000 cycles at a current density of 6 A g−1. Due to the remarkable electrochemical behavior, this work can act as a guiding tool for designing efficient and cost-effective energy storage devices that will hold prodigious potential in commercial energy storage applications.

Manganese substitution effect on physical properties of sol-gel derived DyFeO3 orthoferrite

A simple composite DyFe(1-x)MnxO3 (x = 0, 0.1, 0.3, 0.5) powders were successfully prepared by the sol–gel method. The effect of Mn modification on the structure, thermal and phase transition behaviour of DyFeO3 orthoferrite was investigated. Mn modification didn't show any structural change and all the samples confirmed the pure orthorhombic phase with Pbnm space group. However, a contradicting trend in the variation of lattice parameters were observed due to the presence of mixed oxidation state of Dy, Fe and Mn in the sample leading to oxygen vacancies. The presence of mixed oxidation state was confirmed through X-ray photoemission spectra (XPS). Scanning electron microscopy (SEM) and Williamson Hall (WH) plot confirmed a decrease in particle sizes with increasing Mn concentration leading to an increase in the specific surface area which suggested an inhibition of grain growth with Mn modification. The defects-initiated change in physical behaviour in terms of structural, thermal, microstructural and dielectric are analyzed and discussed in detail.

Structural and photoluminescence investigation of Y2O3:Sm3+ nano‐powders: Organic agent's effect

AbstractIn this article, the authors delve into the synthesis of Y2O3:Sm3+ nanopowders using the sol–gel method, employing organic agents such as ethylene glycol (EG) and polyethylene glycol (PEG). This thorough investigation focuses on the structural, morphological, and photoluminescence characteristics of these nanopowders, with particular consideration for their potential applications in the field of optical devices. X‐ray diffraction patterns indicate that all powders crystallize in pure cubic phases (Ia‐3). Transmission electron microscopy (TEM) analysis reveals the presence of particles with dimensions less than 70 nm. Specifically, morphological and structural data suggest that the crystallite size of nanopowders prepared with PEG exceeds that of nanopowders prepared with EG. In exploring the photoluminescence properties, the emission spectra of the powders, recorded at λem = 600 nm, exhibit two absorption bands attributed to the charge transfer state (CTS) from O2− → Sm3+, with a maximum absorption at 223 nm, and to the intraconfigurational transition 4f5‐4f5 of Sm3+. A red/orange emission, attributed to the 4G5/2 → 6H7/2 transition, predominates under these conditions. A significant improvement in the intensity of photoluminescence is notably observed in samples prepared with organic agents compared to those prepared without agents. Finally, chromatic coordinates underscore the strong potential of Y2O3:Sm3+ nanopowders as promising phosphors for lighting applications.

Factors Affecting Silica/Cellulose Nanocomposite Prepared via the Sol-Gel Technique: A Review.

Cellulose/silica nanocomposites, synthesised through the sol-gel technique, have garnered significant attention for their unique properties and diverse applications. The distinctive characteristics of these nanocomposites are influenced by a range of factors, including the cellulose-to-silica ratio, precursor concentration, pH, catalysts, solvent selection, temperature, processing techniques, and agitation. These variables play a pivotal role in determining the nanocomposites' structure, morphology, and mechanical properties, facilitating tailoring for specific applications. Studies by Raabe et al. and Barud et al. demonstrated well-deposited silica nanoparticles within the interstitial spaces of cellulosic fibres, achieved through TEOS precursor hydrolysis and the subsequent condensation of hydroxyl groups on the cellulose fibre surface. The introduction of TEOS established a robust affinity between the inorganic filler and the polymer matrix, emphasising the substantial impact of TEOS concentration on the size and morphology of silica nanoparticles in the final composites. The successful functionalisation of cellulose fibres with the TEOS precursor via the sol-gel method was reported, resulting in reduced water uptake and enhanced mechanical strength due to the strong chemical interaction between silica and cellulose. In research conducted by Feng et al., the silica/cellulose composite exhibited reduced weight loss compared to the pristine cellulose matrix, with the integration of silica leading to an elevated temperature of composite degradation. Additionally, Ahmad et al. investigated the effects of silica addition to cellulose acetate (CA) and polyethylene glycol membranes, noting an increase in Young's modulus, tensile strength, and elongation at break with silica incorporation. However, concentrations exceeding 4% (w/v) resulted in significant phase separations, leading to a decline in mechanical properties.

Co-precipitation process as an effective and viable route for proton-conducting solid oxide fuel cell applications

BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb) is one of the most popular electrolyte materials in proton ceramic fuel cells (PCFCs). The synthesizing method and properties of BCZYYb powders have a significant impact on the sintering activity of electrolyte materials. In this work, the BCZYYb electrolyte was synthesized by ammonium bicarbonate co-precipitation method (CPT), and was compared with the powder produced by solid-state reaction (SSR) and sol-gel (SG) methods. XRD results show the BCZYYb powder synthesized by the CPT method belongs to orthorhombic crystal system with a space group of Pmcn (No. 62) and the refined lattice parameters are a = 8.774 Å, b = 6.173 Å, and c = 6.203 Å. In humid air atmosphere, the total conductivity at 650 °C and the activation energy for the BCZYYb powder prepared via the CPT method was 2.1 × 10−2 S cm−1 and 0.46 eV, respectively, as compared with 1.9 × 10−2 S cm−1 and 0.45 eV for the SSR method, and 1.8 × 10−2 S cm−1 and 0.44 eV for the SG method. Under similar testing conditions, the measured peak power densities were 0.51, 0.35, and 0.40 W cm−2 at 650 °C for the anode supported PCFCs using electrolyte powder prepared via CPT, SSR and SG methods, respectively, which proves the CPT method is an effective and viable route for PCFCs applications.

Cell viability assessment and ion release profiles of GICs modified with TiO2- and Mg-doped hydroxyapatite nanoparticles

ObjectivesTo assess and compare the cell viability and ion release profiles of two conventional glass ionomer cements (GICs), Fuji IX and Ketac Molar EasyMix, modified with TiO2 and Mg-doped-HAp nanoparticles (NPs). MethodsTiO2 NPs, synthesized via a sol–gel method, and Mg-doped hydroxyapatite, synthesized via a hydrothermal process, were incorporated into GICs at a concentration of 5 wt.%. The biocompatibility of prepared materials was assessed by evaluating their effects on the viability of dental pulp stem cells (DPSCs), together with monitoring ion release profiles. Statistical analysis was performed using One-way analysis of variance, with significance level p < 0.05. ResultsThe addition of NPs did not significantly affect the biocompatibility of GICs, as evidenced by comparable decreased levels in cell viability to their original formulations. Distinct variations in cell viability were observed among Fuji IX and Ketac Molar, including their respective modifications. FUJI IX and its modification with TiO2 exhibited moderate decrease in cell viability, while other groups exhibited severe negative effects. While slight differences in ion release profiles were observed among the groups, significant variations compared to original cements were not achieved. Fluoride release exhibited an initial “burst release” within the initial 24 h in all samples, stabilizing over subsequent days. ConclusionsThe addition of NPs did not compromise biocompatibility, nor anticariogenic potential of tested GICs. However, observed differences among FUJI IX and Ketac Molar, including their respective modifications, as well as induced low viability of DPSC by all tested groups, suggest the need for careful consideration of cement composition in their biological assessments. Clinical significanceThe findings contribute to understanding the complex interaction between NPs and GIC matrices. However, the results should be interpreted recognizing the inherent limitations associated with in vitro studies. Further research avenues could explore long-term effects, in vivo performance, and potential clinical applications.

Multifunctional rare earth oxide/MBG composite microspheres as a carrier for bone tumor treatment

With the development of advanced composites, biomaterials have brought the field of tissue engineering and regeneration into a new era. Among them, composites of inorganic nonmetallic materials and rare earth oxides have unique structures and biochemical properties and have attracted widespread interest. In this work, rare earth oxides (CeO2)/inorganic nonmetallic materials (mesoporous bioactive glass, MBG) composite microspheres (CeO2/MBGs) were synthesized by a sol-gel method, and the in vitro biological effect of CeO2/MBGs was systematically studied. The filling of CeO2/MBGs in irregular bone tumor defects not only promoted osteogenic mineralization in MG63 cells but also had significant antibacterial effects on E. coli and S. aureus. CeO2 enters the MBG network as a network modifier, while doxorubicin (DOX) is adsorbed into the mesoporous structure through electrostatic interactions, which endows CeO2/MBGs with excellent bioactivity and controlled DOX release behavior. Moreover, the results of in vitro experiments showed that the proper addition of rare earth oxides had no toxic effect on normal cells, and the combination of rare earth oxides with antitumor drugs could slow the release of DOX through the use of an intelligent response design system, thus inducing the apoptosis of MG63 cells. This work suggested that combination chemotherapy and the design of a rare earth oxide/MBG composite microspheres may be potential therapeutic approaches for the postoperative repair of bone tumor defects. The construction of this multifunctional rare earth oxide/inorganic biocomposite provides a way to apply the material to bone tissue.

Synthesis, coating, and application of a novel cadmium-free red perovskite quantum dot for micro LED technology

This study successfully creats cadmium-free red perovskite QDs through a chemical solution method. The CsPb(Br0.2/I0.8)3 QDs were synthesized by adjusting the bromine-to-iodine ratio and was customized for red emission wavelengths. The QDs were coated with silicon dioxide (SiO2) using a sol-gel method to protect their luminescent characteristics from moisture and oxygenand enhancing interface modification. Finally, pixelated red perovskite QDs were applied to a blue light display as a color conversion layer. The excess blue light penetration was addressed using a 23-layer distributed Bragg reflector (DBR), which redirected surplus blue light back to the QDs, amplifying red light by 30% with a reduced blue light penetration rate of 0.5%. Future research may involve achieving a regionally colored display by precisely aligning and bonding pixelated perovskite QDs, processed for red and previously studied green quantum dots, onto a pre-prepared blue light display.

Designing a highly near infrared-reflective black nanoparticles for autonomous driving based on the refractive index and principle

HypothesisThe development of highly NIR reflective black single-shell hollow nanoparticles (BSS-HNPs) can overcome the Light Detection and Ranging (LiDAR) sensor limitations of dark-tone materials. The crystalline phase of TiO2 and the refractive index can be controlled by calcination temperature. The formation of hollow structure and the refractive index is expected to simultaneously increase the light reflection and LiDAR detectability. ExperimentsThe BSS-HNPs are synthesized using the sol–gel method, calcination, NaBH4 reduction, and etching to form a hollow structure with true blackness. The computational bandgap calculation is conducted to determine the bandgap energy (Eg) of the white and black TiO2 with different crystalline structures. The blackness of the as-synthesized materials is determined by the Commission on Illumination (CIE) L*a*b* color system. FindingsThe hydrophilic nature of BSS-HNPs enables the formulation of hydrophilic paints, allowing the mono-layer coating. With the synergistic effects of hollow structure and the refractive index, BSS-HNPs manifested superb NIR reflectance at LiDAR detection wavelengths. The high detectability, blackness, and hollow structure of BSS-HNPs can expand the variety of LiDAR-detectable dark-tone materials.

Shape-stable phase change materials based on carboxymethyl chitosan/boron nitride nanosheets high-strength aerogel

The application of phase change materials (PCMs) in energy storage and temperature control systems holds significant promise for enhancing energy efficiency and environmental sustainability. Herein, the development of a boron nitride nano-aerogel-supported PCM, reinforced by carboxymethyl chitosan (CMCS) and oxidized corn starch (DCS) cross-linking was reported. This approach involved the utilization of polydopamine-modified boron nitride nanosheets (PDA@BNNS) for the fabrication of a thermally conductive skeleton, while carboxymethyl chitosan (CMCS) and oxidized corn starch (DCS) were utilized as reinforcing material and cross-linking agent, respectively. The skeleton was prepared via a sol-gel method and freeze-drying technique, while polyethylene glycol (PEG) was subsequently encapsulated using a vacuum impregnation method. Notably, the prepared skeleton exhibits a compressive stress of 12.18 MPa at 80 % strain, much higher than other boron nitride nanosheets aerogels reported in literature. The cross-linked boron nitride skeleton enhances the thermal conductivity of the composites by 137.4 % compared to pure PEG. Furthermore, due to the highly porous structure of the skeleton, the PEG mass fraction reaches 96.0 wt%, resulting in a phase change enthalpy of 181.5 J/g. The results suggest that this composite material is a promising PCM candidate for thermal energy storage applications.

Surface modification of jute-cotton union fabric using TiO2 and ZnO nanoparticles for multifunctional properties

In this study TiO2 and ZnO nanoparticles were employed as a protective coating to impart multifunctional properties, i.e. self-cleaning, water repellency, UV protection and antimicrobial activity onto jute-cotton union fabric. Through the sol-gel method, using titanium (IV) isopropoxide (TTIP) and zinc acetate as precursors, TiO2 and ZnO nanoparticles have been synthesized. Following the dip-pad-dry-cure method along with a 2 wt% of acrylic binder, the synthesized particles were applied on the jute-cotton union fabric. Subsequently, antibacterial activity, self-cleaning properties and physical properties like water absorbency, crease recovery, water vapor permeability, tensile strength, and tear strength of the treated fabric were tested and evaluated. The structural properties of the nano-particles were distinguished by Fourier Transform Infrared Spectroscopy (FTIR) and SEM. Upon comparing the test results of the coated fabric with the uncoated fabric, the results were found to be extremely satisfactory. This study provided valuable insights into the potential of TiO2 and ZnO coating in enhancing properties of jute-cotton union fabric.

Control of Optical Reflection in Ca2MgWO6 by Co and Mo Doping.

To develop novel inorganic red pigments without harmful elements, we focused on the band structure of Ca2(Mg, Co)WO6 and attempted to narrow its bandgap by replacing the W6+ sites in the host structure of Mo6+. Ca2Mg1-xCoxW1-yMoyO6 (0.10 ≤ x ≤ 0.30; 0.45 ≤ y ≤ 0.60) samples were synthesized by a sol-gel method using citric acids, and the crystal structure, optical properties, and color of the samples were characterized. The Ca2Mg1-xCoxW1-yMoyO6 solid solution was successfully formed, which absorbed visible light at wavelengths below 600 nm. In addition, the absorption wavelength shifted to longer wavelengths with increasing Mo6+ content. This is because a new conduction band composed of a Co3d-W5d-Mo4d hybrid orbital was formed by Mo6+ doping to reduce the bandgap energy. Thus, the color of the samples gradually changed from pale orange to dark red, with a hue angle (h°) of less than 35°. Based on the above results, the optical absorption wavelength of the Ca2Mg1-xCoxW1-yMoyO6 system can be controlled to change the color by adjusting the bandgap energy.

Properties experimental investigation of water-based drilling mud contained tragacanth gum and synthesized zinc oxide nanoparticles

Drilling fluids play crucial role in the oil and gas production industry, consequently the optimization of flow behavior of these fluids has received remarkable attention from the beginning of this process. The objective of this study is to improve the rheological and filtration characteristics of water-based mud (WBM) by incorporating zinc oxide (ZnO) nanoparticles (NPs) and affordable tragacanth gum (TG) polymer. Initially, ZnO NPs were synthesized through a facile and straightforward sol–gel method and subjected to comprehensive characterization. Subsequently, these NPs were incorporated into TG polymer solutions to formulate drilling mud samples. The selection of optimal samples involved meticulously determining of ZnO NPs and TG polymer concentrations as influential parameters facilitated by the Design Expert software. The responses taken into consideration in this methodology included flow behavior index (n), consistency index (K), plastic viscosity (PV), and yield point (YP). The investigating rheological parameters entailed utilizing both the Power-law and Bingham-plastic models, underscoring the scholarly refinement of the study’s analytical approach. Subsequently, an analysis of variance (ANOVA) was conducted to assess the significance of the model and its parameters. Three optimal samples were carefully selected based on the results obtained from the modeling and analysis of the rheological parameters. The next phase involved utilizing these optimal samples to investigate their filtration properties in detail. The final step led to selecting the optimal sample composition, which was determined to be 0.25 wt% ZnO NPs and 750 ppm TG polymer based on the optimization results provided by the Design Expert software. Remarkably, this specific combination yielded significant improvements in PV (22.2 %), YP (109.5 %), mud cake thickness (20 %), and fluid loss (2.87 %). Moreover, the resulting mud exhibited desirable rheological properties, including a K of 31.20 (cp) and an n of 0.21. This specific combination was identified as the most favorable composition for achieving the desired rheological and filtration properties.

Microwave assisted synthesis of nickel oxide nanoparticles at different pH via sol gel method: Experimental and first-principles investigations

Nickel oxide (NiO) nanoparticles were synthesized at different pH levels via a sol–gel method and calcined using microwave assistance. The study explored the effects of pH on NiO nanoparticles morphology, structure and electronic properties. Density functional theory (DFT + U) calculations were employed to investigate the structural and electronic properties of the material. NiO synthesized at pH 8 displayed superior crystallinity and particle size distribution, with spherical-like nanoparticles averaging 3 nm in size. DFT + U calculations revealed a band gap of 4.07 eV and a surface energy convergence of 51 meV/Å2, indicating stability. These findings suggest pH 8 as the optimal condition for NiO synthesis. Electrochemical tests demonstrated a high specific capacitance of 87.7F g−1 at a scan rate of 10 mV s−1, indicating promising electrochemical properties for supercapacitor applications.