Ionics最新文献

Three different ionic surfactants (CTAB, SDS, and PEG) were capped synthesized ZnO-NiO nanocomposites via co-precipitation method. The primary goal of the present work is tuning the crystallite size, morphology, particle size, energy gap, and luminescence of ZnO-NiO nanocomposites under the influence of surfactant agents through powder XRD, SEM, UV–visible, and fluorescence measurements. The bi-phase crystalline structure has been identified in synthesized ZnO-NiO samples with the assistance of powder XRD analysis. The TEM image of the CTAB-capped ZnO-NiO composite revealed a uniformly dispersed spherical-like structure of the particles. Further, formations of zinc oxide–nickel oxide have also been supported by the EDX study. The optical band gap values are relatively higher (3.17 eV) in CTAB-capped ZnO-NiO composites than SDS-capped (3.12 eV), and PEG-capped (3.10 eV) through identified as UV–visible spectra. From the fluorescence spectra, strong visible emission peaks were detected at 632 nm in all synthesized ZnO-NiO nanocomposites. The second aim of the present work, in terms of the better size and optical properties of CTAB-capped ZnO-NiO composites, has been taken to further investigate photocatalytic and electrochemical properties through photocatalytic experiments and cyclic voltammetry measurements. Orange Gelb (OG), Amidoblack 10B (AB10B), and Direct Blue 71 (DB71) dyes, along with CTAB-capped ZnO-NiO nanocomposites, were employed as photocatalyst in a photocatalytic experiment under visible light illumination to test the photodegradation efficiency. Photodegradation efficiency of AB10B to be 99.145% is relatively higher than 95.92% (OG) and 94.88% (DB71) which is due to the photo absorption wavelengths of the chromophore and aromatic part of the dyes. In addition, the electrochemical oxidation peaks, current response, and corresponding potential of CTAB-capped ZnO-NiO were shifted under the influence of various scan rates using cyclic voltammetry (CV) analysis, which exhibits pseudocapacitance behavior. This work will pave the way for the synthesized sample’s use in waste-water treatment and supercapacitor applications.

The metal–organic framework (MOF) incorporation in sulfonated poly(ether ketone) (SPEEK) membranes improves the performance of proton exchange membrane fuel cells (PEMFC) that use this filler in the electrolyte. Mesoporous ZrO₂/C and ZnO/C nanocomposites derived from the respective MOFs, Zr-BDC-MOF and Zn-BDC-MOF, were used as fillers in SPEEK to determine the influence of the metal (Zr or Zn) and ligand (terephthalic acid (BDC) or carbon (C)) on the proton conductivity and oxidative stability of proton exchange membranes (PEMs). At a temperature of 100 °C, the results show that adding 7 wt% of Zr-BDC-MOF to SPEEK resulted in 2.5-fold higher proton conductivity than pristine SPEEK. However, water uptake and oxidative stability studies reveal that this membrane loses its chemical stability. The data set shows that the inclusion of 7 wt% ZrO₂/C to SZrC(7) membrane resulted in the best proton conductivity, ca. 2.2-fold higher than SPEEK at 100 °C, making it attractive for application in PEMFC at high temperatures. Our findings show that the influence of the metal used as a filler (Zr or Zn) is lower than that of the ligand (BDC or C) on the oxidative stability and proton conductivity of PEMFC.

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An urgent problem is the bacterial infestations caused by home and industrial wastes that contaminate surface water. This article presents a sustainable and affordable method for synthesizing zinc oxide nanoparticles (ZnO NPs) utilizing Asparagus racemosus root extract. X-ray diffraction, Fourier transform infrared spectroscopy, and UV–visible spectrum analysis were used to characterize the synthesized ZnO nanoparticles. The X-ray diffraction peaks of ZnO NPs matched to a standard JCPDS card (no. 36–1451) and the particles were 21–29 nm in size and had a wurtzite structure with good crystallinity. UV–Vis spectroscopy showed absorption peaks between 359 and 364 nm in ZnO NPs synthesized from Asparagus racemosus root extract. ZnO NPs were confirmed by FTIR, which revealed absorption bands in the 469–525 cm⁻¹ region, showing stretching of the Zn–O bond. In this study, methylene blue (MB) was degraded using ZnO nanoparticles as photocatalysts under the influence of UV light. Notably, the maximum MB decomposition efficiency of 98% was demonstrated by ZnO for 100 mg/mL with reaction rate constants of 0.0312, 0.02104, and 0.001362 min⁻¹ for ASP₁, ASP₂, and ASP₃, respectively. Additionally, the well diffusion technique was used to assess the zone of inhibition, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of ZnO nanoparticles against clinical strains of Escherichia coli and Staphylococcus aureus. ZnO-NPs were more effective against E. coli and S. aureus which exhibited inhibition zones of 13 ± 0.57 and 15 ± 1.15 mm, respectively. These results emphasize the important potential of ZnO nanoparticles produced from biological sources for effective water purification, emphasizing their photocatalytic and antibacterial capabilities.

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Double-perovskite oxide PrBaFe₂O_5+δ (PBF) is considered as a potential electrode material because of its superior oxygen reduction reaction (ORR) activity in air and excellent stability in wet hydrogen atmospheres. However, the electrochemical activities of Fe-based electrode materials are constrained by the oxygen vacancy concentration and oxy-ion transport properties. Herein, PrBaFe_2-xNb_xO_5+δ (PBFNx, x = 0, 0.05, 0.1, 0.15) oxides are synthesized and evaluated as electrodes for symmetrical solid oxide fuel cell (SSOFC). X-ray diffraction (XRD) indicates that PBFNx samples have an orthorhombic structure and good chemical compatibility with electrolyte. Among all the samples, the PBFN0.1 symmetrical half-cell shows the lowest polarization resistance at 800 °C, which decreases by 29.2% compared with that of PBF in air and decreases by 59.9% compared with that of PBF in wet hydrogen atmospheres. The output performance of the single cell with PBFN0.1 as symmetrical electrodes achieves 197.10 mW cm⁻² in wet hydrogen atmospheres at 800 °C, which is an improvement of 31.97% compared with that of PBF. The enhanced electrochemical performance can be attributed to an increase in oxygen vacancy concentrations. The results suggest that the PBFN0.1 material is a potential candidate for SSOFC.

In this present work, lithium nickel vanadate nanoparticles (LiNiVO₄ NPs) were synthesized by solution combustion method. Here, jackfruit seed extract is employed as a fuel for the synthesis. These nanoparticles were characterized by various spectroscopic techniques. X-ray diffraction (XRD) studies confirm the inverse spinel structure of LiNiVO₄ NPs. The scanning electron microscopy (SEM) images represent the agglomerated and clustered-like structure of NPs. Energy dispersive X-ray (EDX) spectrometry shows the existence of vanadium, nickel, and oxygen elements. Also, Ni and V are present in the average ratio of 1:1. The UV–visible spectral analysis indicated absorption bands at 465 and 728 nm, corresponding to a band gap energy of 2.2 eV. The vibrational analysis of the NPs was confirmed through IR and Raman spectroscopy, with a new peak observed at 1036 cm⁻¹ indicating the bond interaction of Li⁺-O-V in the FTIR analysis. Further, LiNiVO₄ NPs exhibit good photocatalytic activity for the degradation of methylene blue (MB) dye under visible light irradiation. And the percentage of degradation efficiency is 91.77 around 180 min. The photocatalytic activity was due to the production of OH radicals during photo irradiation on LiNiVO₄ NPs. The effect of different parameters on photo-catalytic activity was also studied in detail, including dye concentration, catalytic quantity, pH variation, scavenger activity, and recycling of the catalyst. Electrochemical impedance spectroscopy analysis revealed lower charge transfer and good ionic conductivity of LNV NPs, and it is also suitable for supercapacitor preparation.

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Covalent organic frameworks (COFs) have attracted much attention in energy storage due to their porous network structure, large specific surface area, high crystallinity, and pseudocapacitive ability brought by redox reactions. However, the traditional synthesis method of COFs involves toxic solvents and requires high temperatures and pressure. Therefore, it is necessary to develop simple synthesis methods for large-scale practical application of COFs. This study investigated the synthesis and electrochemical properties of two kinds of COFs, which were synthesized through the reflux heating method and solvothermal method using tri(4-aminophenyl)amine (TAPA) and tris(benzaldehyde) (TFB) as monomers. The results indicate that COFs synthesized by the reflux heating method (Re-COF-TAFB) have better specific surface area, thermal stability, and electrochemical properties compared to those synthesized by the solvothermal method (So-COF-TAFB). Re-COF-TAFB has a specific capacitance of 248 F·g⁻¹ at 0.1 A·g⁻¹ and a capacitance retention rate of 104.13% after 10,000 charge and discharge cycles. This paper contributes to understanding COFs’ synthesis methods and their impact on material properties. Reflux heating is highlighted as an efficient technique for developing high-performance COF-based supercapacitors.

This study presents a comprehensive analysis of the intermolecular interactions and diffusion behavior in deep eutectic solvent (DES)-supported poly(acrylate) (PAA) systems, with a focus on enhancing hydronium (H₃O⁺) ion mobility for proton-exchange membranes (PEMs) in fuel cells. Using classical all-atom molecular dynamics (MD) simulations, we investigated the interactions within pure DES-supported PAA and hydrated DES-supported PAA matrices at hydration levels (HLs) 3 and 9. Radial distribution functions (RDFs) revealed significant interactions between the oxygen atoms of PAA and hydrogen atoms of DES components, with distinct variations at different HLs. Interaction energy calculations highlighted the evolving strengths of PAA-DES interactions, especially with choline, chloride, and urea, under varying hydration conditions. Diffusion coefficients indicated substantial enhancements in the mobility of H₃O⁺ ions and water molecules with increasing hydration, essential for effective proton transport. These findings underscore the critical role of water in facilitating dynamic restructuring and efficient proton conduction within the DES-supported PAA matrix, offering valuable insights for the development of advanced PEMs with tailored properties for fuel cell applications.

Photoelectrochemical water splitting is regarded as one of the most efficient methods for hydrogen production, with photoelectrode materials playing a crucial role in enhancing its efficiency. To further improve the effectiveness of hydrogen production via photoelectrochemical water splitting, a lattice Boltzmann method (LBM) with multiple relaxation times (MRT) is employed to simulate the evolution of bubble growth, coalescence, and detachment on the photoelectrode surface. This simulation takes into account factors such as bubble detachment diameter, contact angle of the photoelectrode surface, and the spatial distribution of nucleation sites. According to simulation results, when the gravity coefficient increases, the bubble detachment diameter decreases, a contact angle between 120° and 140° is found to be optimal for bubble detachment. When the contact angle is less than 90°, the bubbles typically adhere to the surface of nucleation sites. The bubble detachment time decreases gradually as the contact angle ranges from 120° to 160°, and the bubble detachment time drops by 1.8 ms and 0.2 ms, respectively. When the distance between two nucleation sites was 5 μm, 10 μm, 15 μm, and 20 μm, and the bubble detachment time was 3 ms, 2.2 ms, 3 ms, and 2.9 ms, respectively. The bubble detachment time could be effectively reduced by appropriately increasing the distance between nucleation sites in a certain range. This study elucidates the behavior of bubbles on photoelectrode surfaces during photocatalytic water decomposition, providing valuable insights for optimizing photoelectrode design and improving the efficiency of hydrogen production.

In the present work, zinc oxide nanoparticles (ZnO NPs) were prepared via a simple and eco-friendly combustion method employing Cleome gynandra seed extract as a fuel. The synthesized ZnO NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray studies (EDX), Fourier-transform infrared spectroscopy (IR), Raman spectroscopy, and UV spectroscopy (UV–Vis). XRD confirmed the crystalline nature of the material with a hexagonal wurtzite structure having an average crystallite size of 28 nm. SEM images confirm the formation of spherical with agglomerated forms of ZnO NPs. FTIR spectrum shows the band at 580 cm⁻¹ due to the vibrational mode of Zn–O bending. The band gap of the ZnO was found to be 3.00 eV. Photocatalytic activity of ZnO NPs was assessed using methylene blue (MB) dye under UV light irradiation, demonstrating an admirable 94% degradation around 120 min. The electrochemical studies of the ZnO-modified carbon paste electrode exhibit superior oxidation and reduction potential and also show promising electrode material for H₂O₂ and ascorbic acid sensors. Further, these NPs also exhibit antioxidant and antimicrobial properties and are biocompatible with lymphocytes. Therefore, the synthesized material has good photocatalytic, electrochemical, antibacterial, and antimicrobial properties.

Water hyacinth is one of the most significant sources of biomass in tropical regions that can be used to create biogas. This strategy aims to improve the sustainability, precise energy content, and ease of transport of the original biofuel feedstock, as well as to extract gases. An experimental investigation on the biomethanation of water hyacinth took place in a semi-batch digester. Temperature, stirring speed, and catalyst concentration all have an impact on the rate of biogas production. The catalyst has been discovered to primarily boost the rate of biogas production from water hyacinth (Eichhornia crassipes). As the catalyst is used here to boost up the biomethanation reaction, the effect of the catalyst on different kinetic parameters is investigated.

The key conclusions of the research indicate that the maximum value of acidogenic cell mass concentration is 0.13 kg/m³d while the minimum value of methanogenic cell mass concentration is 0.014 kg/m³d at 50 ppm catalyst concentration. Moreover, the maximum specific growth rate of the entire process increases as the catalyst concentration rises, reaching a maximum level of 0.312 d⁻¹ at a 50 ppm catalyst concentration. This is proof that using a catalyst can expedite the biomethanation process. As the catalyst concentration increases, so does the overall biomass concentration. Since it increases the precision of the parameter estimates, the simultaneous estimation of the parameters is a crucial part of the estimation process.