Ionics最新文献

In this work, SnO₂ nanoparticles (SnO₂ NPs) were synthesised using a leaf extract from Shorea robusta. The synthetic method was found to be reliable, cost-effective, and efficient. The synthesised SnO₂ NPs have been incorporated with copper (Cu) and used as an electrode material for supercapacitors (SCs). The potential of SnO₂ and its nanocomposite for SCs was investigated using various electrochemical parameters. At a current density of 2 A/g, the maximum specific capacitance of SnO₂@Cu-A, SnO₂@Cu-B, and SnO₂@Cu-C was found to be 220, 226, and 300 F/g. The maximum energy density of 11.1 Wh/kg for SnO₂@Cu-C has been evaluated at a power density of 1021.3 W/kg. After 5000 GCD cycles, a retention of 96.8% was found for SnO₂@Cu-C. Under two electrode systems, a retention of 95.4% was found for SnO₂@Cu-C.

Energy storage devices play a crucial role in all kinds of electronic devices. Rechargeable lithium-ion batteries have run across problems such as energy density, toughness, and safety. In order to conquer these hindrances, in this work, a novel solid-state polymer electrolyte for lithium-ion batteries was synthesized by blending polymethyl methacrylate (PMMA) in poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) with constant weight percent of ethylene carbonate (EC) and lithium bis (trifluoro methane sulfonyl) imide (LiTFSI), and different concentrations of calcium oxide (CaO). The composite polymer electrolytes (CPEs) (PVdF-HFP:PMMA:LiTFSI:EC:CaO) were fabricated using the solution casting technique. Powder XRD reveals enhancement in intensity with increasing CaO content. FTIR shows the interaction between the polymer-salt matrix. Among the analyzed films, PVdF-HFP:PMMA:LiTFSI:EC:CaO (10 wt.%) exhibits high ionic conductivity (10^–4 S/cm) and good electrochemical (4 V) and thermal stability (350℃) which makes it suitable for solid-state electrolyte as a separator in energy storage applications.

Graphical Abstract

Introducing oxygenated species into carbon-based catalysts is an efficient method to enhance the activity of electrochemical hydrogen peroxide (H₂O₂) production. Here, we report a low-temperature plasma strategy for preparing carbon materials rich in epoxy groups. This catalyst exhibits effective electrocatalytic activity, achieving H₂O₂ selectivity over 90% and a Faraday efficiency of 94.9% after 12 h of constant H₂O₂ production. The exceptional electrochemical activity is attributed to the epoxy group species, which are formed through the reaction between carbon defects and oxygen. This work offers an effective approach for preparing carbon-based catalysts for H₂O₂ production and provides insights into the impact of oxygenated species on the activity for H₂O₂ generation.

Bringing microbial fuel cells (MFCs) to market requires the use of non-precious metal catalysts. Therefore, we replaced the platinum (Pt) cathode with more cost-effective cadmium gallate (CdGa2O4) nanoparticles in the present research. The synthesis and characterization of cadmium gallate (CdGa₂O₄), and further its application as a cathode catalyst for oxygen reduction reaction (ORR) in a MFC. The physiochemical characterization indicates a high ORR property of CdGa₂O₄, attributed to the presence of active sites, high electronic conductivity, and high surface area. These features enhanced the bioelectricity production with simultaneous wastewater treatment which resulted into comparable performances to catalysts such as platinum (Pt). The electrochemical analysis shows that the loading rate of CdGa₂O₄ has a significant impact on the power output of the MFC. The highest volumetric power density was observed in CdGa₂O₄ with a loading of 1 mg/cm³ (8.2 W/m³). COD removal efficiency also showed a similar trend with respect to different loading rates. 1 mg/cm³ of CdGa₂O₄ showed the highest COD removal and Columbic efficiency of 83.8% and 11.7%, respectively. The low cost-to-performance ratio, high ORR activity, and high electric conductivity of CdGa₂O₄ prove that CdGa₂O₄ is a feasible substitute for Pt in large-scale operations of MFC.

Graphical Abstract

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.

Graphical Abstract

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.

Graphical Abstract

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.

Graphical Abstract

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.