Simple Sol-gel Method Research Articles

Effect of Bi doping on the electrochemical behaviour of Mg2SiO4 nanoparticle for energy storage applications

Silicate-based compounds are promising nanomaterials due to their high specific surface area, thermal stability, chemical stability, and fast kinetics. In this study, we synthesised pure, 2% Bi-doped, and 4% Bi-doped Mg2SiO4 nanoparticles using a simple and cost-effective sol-gel method. Various techniques such as XRD, FESEM, EDAX, FTIR, Raman, UV-Vis-NIR, cyclic voltammetry (CV), and galvanostatic charge-discharge (GCD) were employed to investigate the prepared samples. XRD patterns confirmed the crystalline phases through phase matching; and the crystallite size, dislocation density, and residual strain were derived. FESEM images showed that pure and Bi-doped Mg2SiO4 have regular spherical shapes and uniform sizes with minimal agglomeration. Particle sizes determined from FESEM images were 49 nm for the pure sample, 42 nm for the 2% Bi-doped sample, and 40 nm for the 4% Bi-doped sample. FTIR and Raman spectra verified the presence of various vibrational modes characteristic of the Mg2SiO4 structure. The UV-Vis-NIR spectra indicated strong absorption in the ultraviolet region upon doping with bismuth. The impact of Bi doping on the electrochemical behaviour of Mg2SiO4 was studied using CV and GCD techniques in a three-electrode system, where the sample-coated Mg foil (active material/activated carbon/polypyrrole) served as the working electrode. GCD curves showed that the 4% Bi-doped Mg2SiO4 electrode exhibited a maximum specific capacitance of 1043 F/g, outperforming the pure and 2% Bi-doped samples. Additionally, the 4% Bi-doped electrode maintained a capacity retention of 80% over 400 cycles. These results suggest that 4% Bi-doped Mg2SiO4 nanoparticles are excellent candidates for electrode material in energy storage applications.

Electrochemical performance of Na4P2O7 decorated Na4MnV(PO4)3/C cathode material for sodium-ion batteries

Na4P2O7 decorated Na4MnV(PO4)3/C (NMVP-SP) composites were prepared by a simple sol–gel method combined with high-temperature calcination in inert atmosphere. As a cathode material for sodium-ion batteries, the optimal NMVP-SP presents much higher capacity, better rate capability and cyclability than Na4MnV(PO4)3/C, which is attributed to Na4P2O7 coating that has good ionic conductivity and inhibits the manganese dissolution from Na4MnV(PO4)3 in electrolyte.

Extraction yield and properties of biogenic silica from palm oil fuel ash: effect of re-ashing pretreatment and solvent concentration

Abstract Pretreatments and extraction conditions can affect the yield and characteristics of biogenic silica (biosilica) from palm oil fuel ash (POFA). This study aimed to examine how reashing pretreatment and varying NaOH concentrations influence the yield and properties of biosilica extracted from POFA by a simple sol-gel method. Re-ashing pretreatment was conducted using a furnace at a temperature of 600°C for 2h. All samples were leached using a citric acid solution. Extraction process was carried out using NaOH solutions with concentrations of 6%, 8%, and 10%). The results showed that re-ashing pretreatment and concentrations of NaOH significantly influenced (p<0.05) the extraction yield, color, crystallinity, and specific surface area of POFA-derived biosilica. Re-ashing pretreatment in combination with a 10% NaOH solution produced the highest extraction yield of biosilica (17.25% w/w) with a bright white color (L=91.83; WI=91.32), SiO2 concentration of 94.68%, crystallinity of 50.10%, and specific BET surface area of 390.80m2/g. XRD patterns confirmed the amorphous nature of POFA-derived biosilica. FTIR spectra revealed the presence of silica functional groups in all samples. This study demonstrated the important roles of re-ashing pretreatment and NaOH concentration in producing POFA-derived biosilica with better yield and properties that could broaden its potential applications.

Synthesis, characterization and estimation of performance parameters of binary ZnO–SnO2/p-Si heterojunction solar cells

The present work demonstrates the successful synthesis of binary ZnO–SnO2 nanocomposite employing a simple and efficient sol-gel method. The XRD spectra confirmed the formation of a highly crystalline domain indexed to (100) planes of ZnO and (101) and (310) planes of SnO2. The UV–vis spectroscopy analysis revealed high transmittance over 85 % and good optical absorption, a desirable aspect for efficiency enhancement of the cell by heightened photo-excited charge carrier generation through an increased number of incident photons being striking at the junction. The optical band gap was determined using the Taucs formula and found to be 3.51 eV. To probe the possible application of ZnO–SnO2 in Heterojunction Solar Cells (HJSCs), we carried out a numerical simulation for the estimation of cell parameters using MATLAB. The result revealed that the work function (WF) does not have a significant effect on short circuit current density (Jsc), whereas the open-circuit voltage (Voc), fill factor (FF) and power conversion efficiency (PCE) significantly depend on the material work function. Typically VOC increased from 0.155 V to 0.665 V, FF increased from 0.586 to 0.838 and the PCE could be enhanced from 2.55 % to 15.74 %, with an estimated WF range of 4.5 eV–4.0 eV. The effect of substrate thickness was also studied, indicating increment in parameters in the range from 25 μm to 200 μm, however, no significant effect was noticed for thickness >200 μm. The simulation provides optimization of semiconductor properties through the estimation of cell parameters such as PCE, Voc, Jsc and FF for enhanced performance.

Finely tuning cobalt valence in Co3O4 lattice through chromium substitution: Regulating the charge transfer and oxygen vacancies for oxygen evolution and methanol oxidation reaction

In this intriguing study, our central focus revolves around efficiency of the Oxygen Evolution Reaction (OER) and methanol oxidation Reaction (MOR) through a captivating approach: harnessing the power of cobalt valence modulation in Cobaltite (Co3O4), achieved by the enchanting substitution of chromium (Cr). By seamlessly integrating chromium atoms into the crystal lattice of Co3O4, our ultimate aim is to orchestrate a remarkable transformation in the potential-determining step of the OER, resulting in a symphony of improved catalytic performance. This substitution is done by utilizing simple sol-gel method at low temperatures. This gentle adjustment of cation valence states creates oxygen vacancies on the spinel surface, achieving an ideal ion ratio of Co2+/Co3+. The formation of spinel oxides has been confirmed by a comprehensive range of precise physicochemical techniques including, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HRTEM), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller (BET) technique and Raman spectroscopy. The presence of oxygen vacancy has been verified with Electron Paramagnetic Resonance (EPR) spectroscopy. The spinel oxide, Cr1.5Co1.5O4 displays superior activity for OER with current density of 100 mA/cm2 at the overpotential of only 413 mV. Our findings highlight the significance of cobalt valence control in promoting OER/MOR activity, paving the way for advanced electrocatalytic systems with enhanced energy conversion capabilities.

Construction of CuFe2O4/Bi2MoO6 heterogeneous catalyst for high-efficiency photocatalytic degradation of levofloxacin under visible light: Mechanism, pathways and DFT calculation

The utilization of solar energy to stimulate semiconductor photocatalytic degradation is a sustainable method for environmental remediation. CuFe2O4/Bi2MoO6 was synthesized for the degradation of levofloxacin by successfully loading CuFe2O4 nanoparticles on the surface of Bi2MoO6 microflower by a simple sol-gel and hydrothermal method. Comprehensive characterizations confirmed the formation of a heterojunction structure between CuFe2O4 and Bi2MoO6. Owning to the strong synergistic effect between CuFe2O4 and Bi2MoO6, involving higher surface area and pore volume, multiple metal ion reaction centers enriched the charge transfer pathways, heterojunction structure facilitated charge migration and reduced electron-hole complexation, the optimal CBM-10 composite catalysts showed high degradation efficiency of LVF with 95.1% in 60 min, and robust structural stability after five cycle experiments. The free radical scavenging test and DFT calculations revealed that three possible reaction pathways for photocatalytic degradation of LVF by combining the analysis of intermediates by HPLC-MS and h+, •O2- and •OH free radical were the main active species.

A Pyrophosphate Bifunctional Cathode with Inductive Effect for High-Voltage and Self-Charging Zinc Ion Battery.

With the growing demand for new energy storage devices, rechargeable aqueous zinc ion batteries (ZIBs) have attracted widespread attention due to their low cost and high safety. Among the cathode materials for ZIBs, polyanionic-based cathode materials with high voltage, high stability, and low cost have great potential. In this paper, tetragonal Na2VOP2O7 was prepared using a simple sol-gel method. The discharge platform voltage amounted to 1.8 V and had good rate and cycle performance due to the inductive effect of pyrophosphate. Then, a protective layer of Zn-hydroxyapatite (ZnHAP) modification was applied to the cathode surface, which can inhibit the hydrolysis of vanadium ions. The capacity was enhanced by 19 % after modification and the capacity retention after 100 cycles was also higher. Interestingly, the Na2VOP2O7 cathode also possesses a self-charging effect, recovering to 48 % of its initial capacity with an open-circuit voltage (OCV) of 1.1 V within a certain period, and light exposure can reduce the self-charging time by 83 %. These beneficial results indicate that the pyrophosphate bifunctional cathode with inductive effect has a great potential to construct high-voltage and multifunctional zinc ion battery.

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.

Sol-gel synthesis of composite adsorbent coating from Prosopis juliflora–activated carbon for simultaneous adsorptive removal of Cd2+ and Cr2O72- from wastewater

ABSTRACT To overcome the challenges associated with powdered activated carbon (PAC) in water and wastewater treatment, the efficacy of composite adsorbent coating (CAC) synthesized using a simple sol-gel method with Prosopis juliflora-activated carbon for the simultaneous reduction of Cd2+ and Cr2O72− was investigated. The CAC was characterized by FTIR (C-H, C = O, and O-H stretching), pHPZC (6 -6.6), SEM (porous-rough surface), and BET surface area (10.6 m2/g) techniques. Statistical analysis confirmed that pH and contact time significantly (p < 0.0001) affected both metal ions removal, with Cd2+ removal generally exceeding that of Cr2O72− due to better ionic properties. Using the optimized conditions (8.5 pH, 0.25 dosage, 5 mg concentration, 105 minutes contact time and 23.73 °C temperature), the predicted and experimental ion removal efficiencies were 86.86 and 83.98% for Cd2+ and 94.26 and 58.08% for Cr2O72−, respectively. The Langmuir adsorption isotherm was the best-suited model (R2 > 0.99), while the metal ions removal was regulated by the PSO kinetic model (R2 > 0.999). The adsorption process was endothermic and spontaneous, as indicated by thermodynamic values (−ΔG°, +ΔH°, +ΔS°). The study demonstrates CAC's effectiveness as an alternative to PAC, offering significant advantages in removing metal ions from wastewater.

Cu@SiO2 catalyst with high copper dispersion for chemoselective hydrogenation of p-chloronitrobenzene

Selective hydrogenation of p-chloronitrobenzene (p-CNB) is not only of significant industrial importance, but also an important model reaction for selectivity investigation. Despite non-precious metal Cu has been proven to be an effective promoter in bimetallic catalysts, Cu as a single active metal achieving both high conversion and high selectivity are rare reported. In this work, Cu@SiO2 catalysts with high specific surface area (509.8–694.3 m2/g), high Cu dispersion (58.4–69.6 %), and small particle size (2.0–3.0 nm) has been prepared by a simple sol–gel method. The catalysts completely suppress the dechlorination reaction, achieving complete conversion of p-CNB with 99.9 % selectivity for p-chloroaniline (p-CAN). Its microstructure, composition, chemical state, adsorption and reaction behavior have been identified by various conventional ex-situ characterizations of catalysts and in-situ DRIFTs of hydrogenation of p-CNB. Interestingly, even at high loadings, Cu in the catalyst could be highly dispersed, thus exhibiting good catalytic activity. In addition, the Cu catalyst exhibits unique adsorption performance towards p-CNB, which perhaps one of the factors for its good performance. This work not only provides a selective hydrogenation catalyst with high Cu dispersion even at high loading amount by a simple method and but also reveals the importance of the adsorption mode of p-CNB, providing guidance for the development of more efficient catalysts in the future.

Preparation of Na3V2(PO4)3 Cathode Materials by Hydrothermal Assisted Sol-Gel Method for Sodium -Ion Batteries

Na3V2(PO4)3 (NVP) cathode material of the sodium ion battery (1 C=117 mAh g-1) has a NASICON-type structure, which not only facilitates the rapid migration of sodium ions, but also has a small volume deformation during sodium ion de-intercalation and the main frame mechanism remains unchanged, and thus is seen as an energy storage material for a wide range of applications, but has a limited electronic conductivity due to its structure. In this paper, NVP cathode materials with finer primary particles are successfully prepared using a simple hydrothermal treatment-assisted sol-gel method. The increased pore size of the NVP materials prepared under the hydrothermal process allows for more active sites and more effective resistance to the volume deformation of sodium ions during insertion/extraction processes, effectively facilitating the diffusion of ions and electrons. The Na3V2(PO4)3 material obtained by the optimized process exhibited good crystallinity in XRD characterization, as well as superior electrochemical properties in a series of electrochemical tests. A specific capacitance of 106.3 mAh g-1 at 0.2 C is demonstrated, compared to 96.5 mAh g-1 for Na3V2(PO4)3 without hydrothermal treatment, and cycling performance is also improved with 93% capacity retention. The calculated sodium ion diffusion coefficient (DNa = 5.68 × 10-14) obtained after EIS curve fitting of the improved sample illustrates that the pore structure is beneficial to the performance of the Na3V2(PO4)3 cathode material.

Investigation of Ethanol gas sensing properties of pristine and Al doped ZnO nanoparticles synthesized by Sol-gel method

Pure and Aluminum-doped Zinc Oxide nanoparticles were prepared by using a simple Sol–gel method. Al contents were varied with 1 wt% and 3 wt% at a fixed concentration of pure ZnO. Synthesized samples were calcinated at 400 °C for 2 h. The results of x-ray diffraction (XRD) confirm that the synthesized nanoparticles have a Hexagonal Wurtzite structure. The average crystallite size of the nanoparticles shows variation from 16 nm to 21 nm. Grain size and surface morphology were investigated with the help of a Field Emission Scanning Electron Microscope (FESEM). Functional groups present in the prepared samples were analyzed by using Fourier Transform Infra-red spectroscopy (FTIR). The percentage response of the fabricated sensor, containing Al-doped ZnO nanoparticles, was examined with exposure to the toxic gas Ethanol. It was observed that percentage response changes due to various sensing parameters like response time and percentage response which, were calculated at 100 ppm and 200 ppm concentrations of toxic Ethanol gas. It was found that with an increase in Al concentration as well as Ethanol ppm level the percentage response of synthesized samples is increased. The maximum percentage response of 17.82 and 20.91 at 100 and 200 ppm with 3 wt% of Al-doped ZnO nanoparticles was observed respectively, which is greater than that of pure ZnO. Also, the same sample shows the lowest response time of 215 s and 120 s at 100 ppm and 200 ppm, respectively. Thus, aluminum doping enhanced the gas sensing response of pristine zinc oxide nanoparticles.

Construction of Uniform LiF Coating Layers for Stable High-Voltage LiCoO2 Cathodes in Lithium-Ion Batteries.

Stabilizing LiCoO2 (LCO) at 4.5 V rather than the common 4.2 V is important for the high specific capacity. In this study, we developed a simple and efficient way to improve the stability of LiCoO2 at high voltages. After a simple sol-gel method, we introduced trifluoroacetic acid (TA) to the surface of LCO via an afterwards calcination. Meanwhile, the TA reacted with residual lithium on the surface of LCO, further leading to the formation of uniform LiF nanoshells. The LiF nanoshells could effectively restrict the interfacial side reaction, hinder the transition metal dissolution and thus achieve a stable cathode-electrolyte interface at high working-voltages. As a result, the LCO@LiF demonstrated a much superior cycling stability with a capacity retention ratio of 83.54% after 100 cycles compared with the bare ones (43.3% for capacity retention), as well as high rate performances. Notably, LiF coating layers endow LCO with excellent high-temperature performances and outstanding full-cell performances. This work provides a simple and effective way to prepare stable LCO materials working at a high voltage.

Influence of Thiol-Functionalized Polysilsesquioxane/Phosphorus Flame-Retardant Blends on the Flammability and Thermal, Mechanical, and Volatile Organic Compound (VOC) Emission Properties of Epoxy Resins.

In this study, thiol-functionalized ladder-like polysesquioxanes end-capped with methyl and phenyl groups were synthesized via a simple sol-gel method and characterized through gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). Additionally, epoxy blends of different formulations were prepared. Their structural, flame-retardant, thermal, and mechanical properties, as well as volatile organic compound (VOC) emissions, were determined using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), TGA, scanning electron microscopy (SEM), limiting oxygen index (LOI), cone calorimetry, and a VOC analyzer. Compared to epoxy blends with flame retardants containing elemental phosphorus alone, those with flame retardants containing elemental phosphorus combined with silicon and sulfur exhibited superior thermal, flame-retardant, and mechanical properties with low VOC emissions. SEM of the residual char revealed a dense and continuous morphology without holes or cracks. In particular, LOI values for the combustion of methyl and phenyl end-capped polysilsesquioxane mixtures were 32.3 and 33.7, respectively, compared to 28.4% of the LOI value for the blends containing only phosphorus compounds. The silicon-sulfur-phosphorus-containing blends displayed reduced flammability concerning the blends using a flame retardant containing only phosphorus. This reflects the cooperative effects of various flame-retardant moieties.

Visible LED active photocatalyst based on cerium doped titania for Rhodamine B degradation: Radical's contribution, stability and response surface methodology optimization

In this study, cerium modified TiO2 catalyst was prepared and the performance on the photocatalytic degradation of Rhodamine B (RhB) in aqueous solution was evaluated. For the band gap engineering, three different percentages of Ce-doped TiO2 (3, 5 and 7 % mol) were synthesized using the simple, efficient, and low-cost sol-gel method. Structural, morphological, and optical analysis, performed by XRD-Rietveld, HRTEM, EDX, XPS and UV–Vis DRS techniques, indicate the formation of nanostructured Ce-doped TiO2 system with anatase phase and band gap in the visible range. Then, Ce-doping percentage, dose of photocatalyst and initial concentration of RhB effects on the removal efficiency were evaluated. The high removal efficiency of 70 % within 150 min was recorded under the condition of: 7 % Ce-doped TiO2 sample, 1.33 g L−1 of dose, and a concentration of RhB of 5 mg L−1. Additionally, a response surface methodology (RSM) was developed for stablish optimal degradation parameters when varying relevant factors for water treatment of real effluents: pH, NaCl, and Cu concentrations. The resulting model shows that the pH is the variable with the highest effect on the photodegradation. Finally, a scavenger study revealed that OH• radicals play a key role in the reaction; and, albeit TOC analysis reveals only 8.55 % of mineralization yield. Cycling study shows that the photocatalyst kept active after 3 cycles of reutilization. The present paper further examinates the parameters affecting Visible LED driven degradation of organic dye in water using Ce-doped TiO2 system and represents an advance in the comprehension of dye degradation with low use of energy.

Interfacial carbon tailoring of porous SiOx/carbon nanotube hybrids towards high-rate lithium storage

Fast charging Lithium-ion batteries (LIBs) is highly required with the massive development of the electric vehicle market. Integrating silicon with carbon nanotubes (CNTs) has shown great promise for constructing high-rate anodes of LIBs. However, current reported silicon axially coated CNTs electrodes fail to provide a robust conductive connection within the interfacial layer, causing unsatisfactory rate performance. In this paper, a series of novel coaxial hollow nanocables of SiOx/C coated CNTs composite were presented based on a simple sol–gel method and subsequent calcination. Due to the uniform composition of carbon and SiOx at sub-nanometer scale in the coating layer, a strong 3D conductive network is formed between the internal carbon nanotubes and the neighboring electrode particles. When utilized as LIBs anodes, such novel hybrids manifest high reversible capacity (511 mA h g−1 remained after 500 cycles at 0.5 A g−1), high-rate capability (232 mA h g−1 at 5 A g−1) and ultra-long high-current cycling stability (396 mA h g−1 remained after 1000 cycles at 1.0 A g−1). The structural characterization and electrochemical dynamics analysis show that the synergistic effect of abundant mesoporous channels in the coating layer and strong carbon 3D conductive network makes this unique composite structure exhibit excellent electrochemical performance. This work sheds novel light on the wisely design of advanced Si-based anodes with enhanced fast charging performance.

High performance Co3O4/Sn-ZnO nanocomposite photocatalyst for removal of methylene blue dye

Methylene blue is a toxic, carcinogenic, and non-biodegradable synthetic dye discharged from factories and industries that causes severe harm to human health and environmental pollution. Therefore, in this work, Co3O4/Sn-ZnO nanocomposite was synthesized using a simple sol–gel method for efficient photocatalytic removal of methylene blue dye in an aqueous basic medium. The structural, optical, photoluminescence, morphological, and compositional properties were studied. The XRD result revealed that the crystal size increases as the full width at half maxima (FWHM) decreases when Co3O4 are coupled with Sn-ZnO. From UV-visible diffusive reflectance and photoluminescence spectroscopies, a narrowing of the band gap and a reduction of the charge carrier’s recombination rate were observed, respectively. The photocatalytic efficiency and degradation rate constant of 95.1% and 0.03251 min−1 were recorded for methylene blue dye upon the use of optimized catalyst dosage of 60 mg Co3O4/Sn-ZnO nanocomposite catalyst under an irradiation time of 100 min at room temperature for optimized pH value of 9 in an aqueous basic medium.

Unraveling the modified mechanism of ruthenium substitution on Na3V2(PO4)3 with superior rate capability and ultralong cyclic performance

Na3V2(PO4)3(NVP) is an ideal cathode material for sodium ion battery due to its stable three-dimensional frame structure and high operating voltage. However, the low intrinsic conductivity and serious structural collapse limit its further application. In this work, a simultaneous optimized Na3V1.96Ru0.04(PO4)3/C@CNTs cathode material is synthesized by a simple sol–gel method. Specifically, the ionic radius of Ru3+ is slightly larger than that of V3+ (0.68 Å vs 0.64 Å), which not only ensures the feasibility of Ru3+ replacing V3+ site, but also appropriately expands the migration channel of sodium ions in NVP and stabilizes the structure, effectively improving the diffusion efficiency of sodium ions. Moreover, CNTs construct a three-dimensional conductive network between the grains, reducing the impedance at the interface and effectively improving the electronic conductivity. Ex-situ XRD analysis at different SOC were performed to determine the change in the crystal structure of Ru3+doped Na3V2(PO4)3, and the refinement results simultaneously demonstrate the relatively low volume shrinkage value of less than 3 % during the de-intercalation process, further verifying the stabilized crystal construction after Ru3+ substitution. Furthermore, the ex-situ XRD/SEM/CV/EIS after cycling indicate the significantly improved kinetic characteristics and enhanced structural stability. Notably, the modified Na3V1.96Ru0.04(PO4)3/C@CNTs reveals superior rate capability and ultralong cyclic performance. It submits high capacities of 82.3/80.9 mAh g−1 at 80/120C and maintains 71.3/59.6 mAh g−1 after 14800/6250 cycles, indicating excellent retention ratios of 86.6 % and 73.6 %, respectively. This work provides a multi-modification strategy for the realization of high-performance cathode materials, which can be widely applied in the optimization of various materials.

Design and synthesis of active site rich cobalt tin sulfide nano cubes: An effective electrochemical sensing interface to monitor environmentally hazardous phenolic isomers

In the present study, we synthesized Cobalt Tin Sulfide Nano Cubes (CoSnS2) using a simple sol–gel method, and the structural and morphological characterizations were performed to confirm the effectiveness and feasibility of the approach without any impurities. Further, to serve as an electrochemical interface for sensing dihydroxy benzene isomers (DHBIs), CoSnS2 nanoparticles were drop cast on the surface of the glassy carbon electrode (GCE). From the electrochemical characterizations, CoSnS2/GCE shows improved electrochemical performance than bare GCE, and can selectively detect DHBIs. The limits of detection (LODs) calculated for individual determination of catechol (CC) and hydroquinone (HQ) at CoSnS2/GCE was 10.21 nM (5.0–135.0 µM) and 12.56 nM (5.0–135.0 µM), respectively. Also, possible interference does notgreatly affect the analytical performance ofthe modified electrode.Overall, we investigated the simple synthesis of transitional-metal sulfides (TMSs) and their electrochemical sensing applications to chemicals that are dangerous to the environment. We anticipate that the easy approach proposed herein will be very attractive for producing and commercializingelectrochemical sensing devices in the future.

Boosting the acid penetration barrier of epoxy-silica organic-inorganic hybrid coating via adjusting its molecular structures: Experimental and molecular dynamics simulation study

The permeability barrier property of coatings against corrosive media determines their service life. Herein, the molecular structure of epoxy-silica organic-inorganic hybrid (OIH) coating is regulated to endow the coatings with enhanced barrier properties by a simple sol-gel method. Experiments show that the coating with 8% Si-O-Si structure has the best acid penetration resistance after 45 days of immersion in 10 wt.% H2SO4 solution. In addition, molecular dynamics simulation results show that the molecular structure of OIH affects the densification of the coating, forming a highly cross-linked network structure that inhibits the diffusion and destructive effects of corrosive media and thus affects the acid penetration resistance of the coating.