نتایج جستجو برای: nafion
تعداد نتایج: 1409 فیلتر نتایج به سال:
The current study investigated the unique combination of alloying (Pt with Cr) and Nafion stabilisation to reap the benefits of catalyst systems with enhanced catalytic activity and improved durability in PEMFCs. Pt–Cr alloy nanoparticles stabilised with Nafion were chosen in the current study owing to their higher stability in acidic and oxidising media at high temperatures compared to other P...
This work summarizes the electrochemical response of flavanone carbon composite electrodes in comparison with Nafion®-coated electrodes, for use as voltammetric pH sensors both buffered and low-buffered media. Square wave measurements suggest peak potential achieved from polymerization after electron-proton oxidation responds accuracy to solutions coated non-coated a shift 55.1 mV 54.6 per unit...
Free-standing, membrane-embedded, Si microwire arrays have been used to affect the solar-driven, unassisted splitting of HI into H2 and I3 . The Si microwire arrays were grown by a chemical-vapor-deposition vapor–liquid–solid growth process using Cu growth catalysts, with a radial np junction then formed on each microwire. A Nafion proton-exchange membrane was introduced between the microwires ...
The nature of tip-sample interaction forces in atomic force microscopy (AFM) phase imaging strongly affects the resolution of proton conducting domains mapped at the surface of Nafion membranes. Images acquired in repulsive mode overestimated the area of individual proton conducting domains by a factor of 4 (360 vs 90 nm(2)) and underestimated the number of these domains by a factor of 3 (0.9 d...
Proton exchange membranes (PEMs) play an important role in the fuel cell systems. A good PEM must meet a series of requirements such as high proton conductivity, excellent mechanical strength and stability, chemical and electrochemical stability, low fuel crossover, etc. Nafion is currently the most commercially utilized electrolyte membranes for polymer electrolyte fuel cells, with high chemic...
Vibrational analysis of triflic acid (TfOH) at different water uptakes was conducted. This molecule mimics the sulfonate end of the Nafion side-chain. As the proton leaves the sulfonic acid group, structural changes within the Nafion side-chain take place. They are revealed by signal shifts in the infrared spectrum. Molecular modeling is used to follow structural modifications that occur during...
Nafion films incorporating cationic nickel complexes [Ni(II)(acac)(R4en)](+) (acac = acetylacetonato, R4en = tetraalkylethylenediamine) that exhibit chromic behavior in response to temperature changes and solvent molecules in the vapor and liquid phases have been prepared.
Membrane extraction is a widely employed technique for improving the sensitivity and/or selectivity of a chemical analysis. This paper reports a study on the membrane extraction of aqueous transition metal ions using commercially available Nafion gas dryer assemblies. Though designed and marketed for use with gaseous mixtures, results of this work indicate such assemblies can be effective for t...
Various polybenzimidazole (PBI)-based ion-exchange films were prepared and thoroughly characterized by Fourier transform infrared (FT-IR) spectroscopy, proton conductivity, and water uptake for possible use as fuel cell membranes. Upon the increase in the flexibility of the PBI-based polymer films (e.g., poly(oxyphenylene benzimidazole) (OPBI) and sulfonated OPBI (s-OPBI)), the membranes exhibi...
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