This study investigates the synthesis and electrocatalytic performance of cobalt oxide (Co3O4) nanoparticles for the oxygen evolution reaction (OER) and their role in water treatment as contaminant removal agents. Cobalt oxide nanoparticles are recognized as promising materials in electrocatalysis due to their tunable properties and nanoscale engineering potential. Here, fine cobalt oxide nanoparticles are synthesized using the sol-gel method followed by various sintering temperatures to achieve precise control over surface morphology, size, and shape. Characterization via high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM) elucidates the impact of sintering temperature on nanoparticle properties. Thin film electrodes of cobalt oxide are fabricated using the doctor blade method and evaluated using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Among the tested sintering temperatures, cobalt oxide electrodes sintered at 600 °C exhibit superior catalytic activity, demonstrating an overpotential of 258 mV (vs RHE) at 10 mA cm-2 current density and a Tafel slope of 17.33 mV dec-1. Furthermore, these electrodes demonstrate excellent stability, maintaining OER performance for 10 h in 1 M NaOH electrolyte. Additionally, the role of cobalt oxide nanoparticles in water treatment is explored using inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental results reveal that lower sintering temperatures enhance the electrocatalytic properties of cobalt oxide nanoparticles, highlighting their potential contribution to sustainable energy and water treatment technologies. This work underscores the significance of cobalt oxide nanoparticles as dual-functional materials for advancing electrocatalysis and water purification applications, thus paving the way for the development of efficient and environmentally friendly technologies.

Various copper-related defects in the absorption layer have been a key factor impeding the enhancement of the efficiency of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells. Alkali metal doping is considered to be a good strategy to ameliorate this problem. In this article, Rb-doped CZTSSe (RCZTSSe) thin films were synthesized using the sol-gel technique. The results show that the Rb atom could successfully enter into the CZTSSe lattice and replace the Cu atom. According to SEM results, a moderate amount of Rb doping aided in enhancing the growth of grains in CZTSSe thin films. It was proven that the RCZTSSe thin film had the densest surface morphology and the fewest holes when the doping content of Rb was 2%. In addition, Rb doping successfully inhibited the formation of CuZn defects and correlative defect clusters and promoted the electrical properties of RCZTSSe thin films. Finally, a remarkable power conversion efficiency of 7.32% was attained by the champion RCZTSSe device with a Rb content of 2%. Compared with that of un-doped CZTSSe, the efficiency improved by over 30%. This study offers new insights into the influence of alkali metal doping on suppressing copper-related defects and also presents a viable approach for improving the efficiency of CZTSSe devices.

This study presents a novel approach for the fabrication of a Co,Ni/MoS2-derived nanohybrid material using wheat straw extract. The facile synthesis method involves a sol-gel process, followed by calcination, showcasing the potential of agricultural waste as a sustainable reducing and chelating reagent. The as-prepared nanohybrid has been characterized using different techniques to analyse its physicochemical properties. X-ray diffraction analysis confirmed the successful synthesis of the nanohybrid material, identifying the presence of NiMoO4, CoSO4 and Mo17O47 as its components. Fourier-transform infrared spectroscopy differentiated the functional groups present in the wheat straw biomass and those in the nanohybrid material, highlighting the formation of metal-oxide and sulphide bonds. Scanning electron microscopy revealed a heterogeneous morphology with agglomerated structures and a grain size of around 70 nm in the nanohybrid. Energy-dispersive X-ray spectroscopy analysis shows the composition of elements with weight percentages of (Mo) 9.17%, (S) 6.21%, (Co) 12.48%, (Ni) 12.18% and (O) 50.46% contributing to its composition. Electrochemical analysis performed through cyclic voltammetry showcased the exceptional performance of the nanohybrid material as compared with MoS2, suggesting its possible applications for designing biosensors and related technologies. Thus, the research study presented herein underscores the efficient utilization of natural resources for the development of functional nanomaterials with promising applications in various fields. This study paves a way for manufacturing innovation along with advancement of novel synthesis method for sustainable nanomaterial for future technological developments.

This research enhances ethanol sensing with Fe-doped tetragonal SnO2 films on glass, improving gas sensor reliability and sensitivity. The primary objective was to improve the sensitivity and operational efficiency of SnO2 sensors through Fe doping. The SnO2 sensors were synthesized using a flexible and adaptable method that allows for precise doping control, with energy-dispersive X-ray spectroscopy (EDX) confirming homogeneous Fe distribution within the SnO2 matrix. A morphological analysis showed a surface structure ideal for gas sensing. The results demonstrated significant improvement in ethanol response (1 to 20 ppm) and lower temperatures compared to undoped SnO2 sensors. The Fe-doped sensors exhibited higher sensitivity, enabling the detection of low ethanol concentrations and showing rapid response and recovery times. These findings suggest that Fe doping enhances the interaction between ethanol molecules and the sensor surface, improving performance. A mathematical model based on diffusion in porous media was employed to further analyze and optimize sensor performance. The model considers the diffusion of ethanol molecules through the porous SnO2 matrix, considering factors such as surface morphology and doping concentration. Additionally, the choice of electrode material plays a crucial role in extending the sensor\'s lifespan, highlighting the importance of material selection in sensor design.

Titanium dioxide (TiO2) thin films prepared by the sol-gel technique have been shown to be optically isotropic and, unlike the films obtained by competitive methods, do not exhibit measurable birefringence. A series of submicrometer-thin titanium dioxide films were prepared using the sol-gel technique and then thermally annealed at different temperatures. The samples were analyzed by spectroscopic ellipsometry using the Mueller matrix formalism, X-ray diffractometry and scanning electron microscopy. The conversion of amorphous titanium dioxide to polycrystalline anatase occurred at 400 °C or higher. Crystallites of a few percent of the film thickness were observed. Nevertheless, the crystallization process did not trigger the appearance of birefringence. These observations demonstrate that high-quality planar optical waveguides can be successfully fabricated on flexible substrates, in particular those composed of efficient polymers that can withstand the aforementioned temperatures.

The sol-gel process enables the preparation of silica-based matrices with tailored composition and properties that can be used in a variety of applications, including catalysis, controlled release, sensors, separation, etc. Commonly, it is assumed that silica matrices prepared via the sol-gel synthesis route are \"inert\" and, therefore, do not affect the properties of the substrate or the catalyst. This short review points out that porous silica affects the properties of adsorbed/entrapped species and, in some cases, takes an active part in the reactions. The charged matrix affects the diffusion of ions, thus affecting catalytic and adsorption processes. Furthermore, recent results point out that ≡Si-O. radicals are long-lived and participate in redox processes. Thus, clearly, porous silica is not an inert matrix as commonly considered.

OBJECTIVE: This study developed a sol-gel tricalcium silicate/graphene oxide (TCS-GO) composite and examined its physicochemical properties, antimicrobial activity, and osteo/odontogenic effect on dental pulp stem cells.
METHODS: Tricalcium silicate was synthesized and combined with graphene oxide at three different concentrations, namely 0.02%, 0.04%, and 0.08% w/w, while tricalcium silicate and mineral trioxide aggregate served as controls. The setting time, compressive strength, pH, and calcium ion release of the composites were evaluated, as well as antimicrobial properties against Streptococcus mutans and Lactobacillus acidophilus. Additionally, the viability of dental pulp stem cells; apatite forming ability; and the gene expression of Alkaline phosphatase, Dentin sialophosphoprotein, and Runt-related transcription factor 2 were assessed.
RESULTS: TCS-GO (0.08%) showed a significantly shorter setting time and higher compressive strength when compared to MTA (p < 0.05). Additionally, tricalcium silicate and TCS-GO groups showed a higher release of Ca ions than MTA, with no significant difference in pH values among the different groups. TCS-GO (0.08%) also demonstrated a significantly stronger antimicrobial effect against Lactobacillus acidophilus compared to MTA (p < 0.05). ALP expression was higher in TCS-GO (0.08%) than MTA on days 3 and 7, while DSPP expression was higher in TCS-GO (0.08%) than MTA on day 3 but reversed on day 7. There was no significant difference in RUNX2 expression between TCS-GO (0.08%) and MTA on days 3 and 7.
CONCLUSIONS: The TCS-GO (0.08%) composite demonstrated superior physicochemical characteristics and antimicrobial properties compared to MTA. Moreover, the early upregulation of ALP and DSPP markers in TCS-GO (0.08%) indicates that it has the potential to promote and enhance the osteo/odontogenic differentiation of DPSCs.

Ba1-xCexMnO3 (BM-Cex) and Ba1-xLaxMn0.7Cu0.3O3 (BMC-Lax) perovskite-type mixed oxides were synthesized using the sol-gel method adapted for aqueous media with different values of x (0, 0.1, 0.3, 0.6) to estimate the effect of the degree of the partial substitution of Ba by Ce or La on the structure and properties that are relevant for their use as catalysts for gasoline direct injection (GDI) soot oxidation. The samples were deeply characterized by ICP-OES, XRD, XPS, N2 adsorption, H2-TPR, and O2-TPD, and their potential as catalysts for soot oxidation has been analyzed in various scenarios that replicate the exhaust conditions of a GDI engine. By comparing the catalytic performance for soot oxidation of the two tested series (BM-Cex and BMC-Lax) and in the two conditions used (100% He and 1% O2 in He), it could be concluded that (i) in the absence of oxygen in the reaction atmosphere (100% He), BMC-La0.1 is the best catalyst, as copper is also able to catalyze the soot oxidation; and (ii) if oxygen is present in the reaction atmosphere (1% O2/He), BM-Ce0.1 is the most-active catalyst as it presents a higher proportion of Mn(IV) than BMC-La0.1. Thus, it seems that the addition of an amount of Ce or La higher than that corresponding to x = 0.1 in Ba1-xCexMnO3 and Ba1-xLaxCu0.3Mn0.7O3 does not allow us to improve the catalytic performance of BM-Ce0.1 and BMC-La0.1 for soot oxidation in the tested conditions.

Nasal administration can bypass the blood-brain barrier and directly deliver drugs to the brain, providing a non-invasive route for central nervous system (CNS) diseases. Inspired by the appearance that a gate can block the outside world and the characteristics of the sol-gel transition can form a \"gate\" in the nasal cavity, a Drop to Gate nasal drop (DGND) is designed to set a gate in nose, which achieves protecting role from the influence of nasal environment. The DGND demonstrates the efficiency and application prospect of delivering drugs to the brain through the N-to-B. The effective concentration of single administration is increased through the hydrophobic interaction between C8-GelMA and SRT1720 (SA), and then cross-linked under UV to form nanogel, which can respond to MMP in the inflammatory microenvironment of sepsis-induced cognitive dysfunction. Finally, the SA/nanogel is compounded into the thermogel, which can respond to the nasal cavity temperature to form DGND in situ, increasing the residence time and delivery efficiency of drugs in the nasal cavity. In vitro, the DGND alleviates lipopolysaccharides (LPS)-induced BV2 inflammation. In vivo, DGND effectively targets the nasal mucosa and deliver drugs to the brain, which activate Sirt1 to alleviate inflammation mediated by microglia and improve cognitive dysfunction in sepsis mice.

This study examined the influence of growth temperature and dopant concentration on the properties of Gd- and Ni-doped zinc oxide nanorods (ZnO NRs). ZnO seed layers were deposited on glass substrates using a sol-gel and dip-coating approach. Gd- and Ni-doped ZnO NRs were hydrothermally grown on the seed layers at different temperatures such as 75, 90, and 105°C for a constant growth time of 5 h. The crystal structure, optical, surface morphology views, and electrical properties of the NRs were extensively investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy, and four probe experimental methods. The XRD analysis confirmed the successful substitution of Zn2+ ions by Gd3+ and Ni2+ within the ZnO main matrices. The reordering of hexagonal structures with varied electronegativity, ionic radius dimensions, and valence electron states of Gd and Ni dopants affected seriously the fundamental characteristic features of NRs. The SEM images showed that the ZnO NRs grown at 90°C possessed a more favorable surface morphology and well-defined hexagonal shape compared with those grown at other growth temperatures. Higher dopant concentration led to an increase in NR diameter but a decrease in density depending on the increase in the space between the NRs. Additionally, the optical transmittance was found to generally enhance with increasing dopant concentration. The results obtained highlighted the interplay between growth temperature, dopant type and concentration in tailoring the structural, morphological, and optical properties of Gd- and Ni-doped ZnO NRs, paving the way for the development of optimized nanomaterials for various applications. RESEARCH HIGHLIGHTS: The XRD analysis confirmed the successful substitution of Zn2+ ions by Gd3+ and Ni2+ within the ZnO main matrices. The SEM images showed that the ZnO NRs grown at 90°C possessed a more favorable surface morphology and well-defined hexagonal shape compared with those grown at other growth temperatures. The optical transmittance was found to generally enhance with increasing dopant concentration. The results obtained highlighted the interplay between growth temperature, dopant type and concentration in tailoring the structural, morphological, and optical properties of Gd- and Ni-doped ZnO NRs, paving the way for the development of optimized nanomaterials for various applications.