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This study investigated the potential enhancement of proton conductivity in Nafion membranes through the incorporation of sulfo ethyl cellulose (SEC) at varying weight ratios (5 and 10 wt.%). Results indicated that increasing the weight ratio of SEC led to improvements in water absorption, activation energy, and proton conductivity within the composite membranes. Specifically, the composite membrane exhibited a significant increase in proton conductivity, reaching up to 170 mS cm−1, in contrast to the pristine Nafion membrane which recorded 40.08 mS cm−1, particularly at temperatures exceeding 120°C. At the sub‐molecular level, Fourier transfer inferred spectroscopy (FTIR) analysis of Nafion/SEC membranes unveiled cross‐linking interactions occurring between the sulfo acid groups of Nafion chains and the hydroxyls within the SEC matrix. Moreover, X‐ray diffraction (XRD) findings of the composite membranes were instrumental in identifying crystalline phases, orientation, and structural features. The results indicated variations in atomic radius and alterations in lattice parameters at the nanoscale, induced by heightened surface forces resulting from the inclusion of SEC in the Nafion matrix. This phenomenon leads to a reduction in crystallite size, accompanied by an increase in peak broadening and surface area within the composite membranes. Such changes signify a clear interaction between SEC and Nafion, as confirmed by both scanning electron microscopy and thermal gravimetry analyses. Taken together, these findings strongly indicate that the cross‐linked composite membranes utilizing SEC‐Nafion hold significant promise as proton exchange membranes. [ABSTRACT FROM AUTHOR]

In this research work, the synthesis and characterization of new ion exchange membranes made from sulfonated polyether sulfone (S--PES) crosslinked by aminated PES (NH2--PES) crosslinking reagent have been investigated for electrodialysis (ED) applications. Sulfonated and aminated PES have similar chemical structures that allow a good compatibility, the only difference between them is their functional groups. This membrane (called HNH2) has been obtained by reaction between S--PES with 1.3 S[O.sub.3]H groups per monomer unit and the calculated equivalent amount of NH2--PES. Three HNH2 membranes have been fabricated with different degrees of sulfonation. The HNH2 membranes properties have been evaluated using different characterization analysis. The results have shown that HNH2 membranes appear to be very promising candidates for electrochemical applications. KEYWORDS conductivity, crosslinking, desalination, Electrodialysis, HNH2 membrane, ion exchange membrane, 1 | INTRODUCTION Electrodialysis (ED) is an electro-membrane separation technology that has gained increasing attention in the industrial world because of its robustness, efficiency, low cost of maintenance, and versatility. [...]

This work deals with the synthesis of SiO2@TiO2 supported palygorskite fibers and their use as a filler for proton exchange membrane fuel cells in order to improve their performance. SiO2@TiO2‐palygorskite nanostructured particles were synthesized separately with original route to ensure the growth of TiO2 and then of SiO2 on the surface of the clay. Accordingly, the introduction of the synthetic filler (SiO2@TiO2‐paly) into the electrolyte membrane (Nafion) aims to improve mechanical, thermal, and proton conductivity properties. The TiO2 nanoparticles were generated via a sol–gel process on the external surface of palygorskite. Then, SiO2 nanoparticles were synthetized using a similar sol–gel process, onto the TiO2‐palygorskite particles to produce the final SiO2@TiO2‐palygorskite particles. The physico‐chemical properties of the nanostructured particles were studied by X‐ray diffractometry, Fourier transform infrared, scanning electron microscopy, and transmission electron microscopy. Nafion based composite membranes were prepared using SiO2@TiO2‐palygorskite and TiO2‐palygorskite as a control standard. The composite membranes show improved mechanical properties, thermal stability, water retention, and proton conductivity compared to the neat Nafion membrane. Proton conductivities (at 100°C and 100% relative humidity) increased from 65.0 mS/cm for neat Nafion to 70.4 mS/cm and to 128.6 mS/cm when incorporated TiO2‐Paly (6% in weight) and SiO2@TiO2‐Paly (6% in weight), respectively. [ABSTRACT FROM AUTHOR]

Sulfonated poly(ether ether ketone) (SPEEK) with a low sulfonation degree was blended using nanofiller layered double hydroxide (LDH, Mg2AlCl)/sepiolite nanostructured material as additive to use as an electrolyte membrane for fuel cell application. Characterization assessments, that is, mechanical stability, thermal gravimetric analysis, ion exchange capability, swelling properties, water uptake capacities, electrochemical impedance spectroscopy analysis, and Fourier transform infrared spectroscopy of the composite membranes were conducted. The presence of LDH/sepiolite nanoarchitectured material within SPEEK was found to have the highest water retention and proton conductivity value at high temperature rather than LDH/SPEEK and pristine SPEEK membranes. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) with a low sulfonation degree was blended using different proportions of sodium rich Smectite clay (3 and 6 wt%) to use as an electrolyte membrane for fuel cell application. The structural functionalities, surface morphologies, and the thermal stability of the resultant composite membranes were characterized using Fourier‐transform infrared spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy, atom force microscopy, and thermo‐gravimetric analysis. FT‐IR showed that no chemical reactions take place between the sulfonated polyether ether ketone (SPEEK) and the clay with different ratios. XRD diffractograms illustrated a lower degree of crystallinity of the blended SPEEK than pristine SPEEK. The elaborated composite membranes proved to have a higher thermal stability than SPEEK. Furthermore, the SPEEK/clay composite membranes with 3 and 6 wt% in clay loading had higher water uptake and lower methanol uptake than those in pristine SPEEK It was also shown that, the incorporation of sodium ions rich Smectite clay layers between the clusters in SPEEK improved the conductivity to 2 × 10−2 S/cm at 140°C (for 6 wt% in clay) without compromising the dimensional stability of the composite membranes. These results propose the composite membranes as a potential candidate for methanol fuel cells at temperatures above 120°C making SPEEK composite membrane competitive to that of Nafion membrane. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical properties of natural or synthetic ferruginous clays, nontronite, montmorillonite and saponite, were studied by cyclic voltammetry and impedancemetry. Clay modified electrodes were then tested for the reduction of hydrogen peroxide under different conditions: in acidic medium without redox mediator, in phosphate buffer solutions (pH 7 or 8) with a redox cation (methyl viologen, MV2+) or a biomolecule (hemoglobin, Hb) absorbed within the clay coating. In all cases, the presence of iron species in the octahedral lattice of the clays enhanced the electrocatalytic reduction currents of H2O2. The sensitivities of H2O2 calibration curves were 0.23, 54 and 132mA/Mcm2 for Nont, MV2+-Nont and Hb-Nont modified electrodes, respectively. [Copyright &y& Elsevier]