31 documents found, page 1 of 4
New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)
Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.A new paradigm for energy is underway demanding decarbonized energy systems. Some of them rely on emerging electrochemical devices, crucial in hydrogen technologies, including fuel cells, CO2 and water electrolysers, whose applications and performances depend on key components such as their separators/ion-exchange membranes. The most studied and already commercialized Nafion membrane shows great chemical stabil...
New proton exchange membranes based on ionic liquid doped chitosan
Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.; Naffati, NaimaThe development of new proton exchange membranes (PEM) for electrochemical devices have attracted re searcher’s attention in the pursuit for more sustainable and cost-effective technologies for clean energy pro duction and conversion. In this work, new doped chitosan (CS) membranes were prepared by the casting method. Chitosan is an abundant, biodegradable and non-toxic material, and as a membrane, a sustaina...
New Modified SPEEK-Based Proton Exchange Membranes
Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.A decarbonized society demands cleaner and sustainable energy sources based on well-established or emerging technologies with the potential to make a significant contribution to energy storage and conversion, such as batteries, fuel cells and water and/or CO2 electrolyzers. The performance of these electrochemical devices relies on key components such as their separators/ion-exchange membranes. The most common ...
Chemical stability of new nafion membranes doped with bisphosphonic acids under...
Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.The development of new proton exchange membranes for PEM technology in fuel cells and electrolysers with increased durability is paramount to system's lifetime and scalability. In this work, new modified Nafion membranes doped with bisphosphonic acids are proposed with increased resilience to chemical degradation by H2O2/Fe2+, mimicking ex-situ radical attack to membrane structure. Relevant properties were eval...
New triazine-phosphonate dopants for proton exchange membranes (PEM)
Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.g their operating temperature range. Our previous studies have demonstrated that the incorporation of aryl or heterocyclic phosphonic acid dopants into Nafion, by casting, results in an enhancement of the proton conductivity1-4 and stability5 of the Nafion doped membranes. This work reports the synthesis and characterization of a new series of triazine-phosphonate derivatives for use as dopants in the preparati...
New proton conductive membranes of indazole- and condensed pyrazolebisphosphoni...
Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.In this work, new doped Nafion membranes for PEMFC are prepared by casting with 1 wt% loading of the prepared indazole- and condensed pyrazolebisphosphonic acids (AzBPs). The new membranes were analysed by ATR-FTIR spectroscopy and their morphology was examined by SEM. Membranes were evaluated for water uptake and ion exchange capacity (IEC), and their hydration number was estimated. The proton conduction proper...
Study of the degradation of Nafion modified membranes
Teixeira, António P. S.; Teixeira, Fátima C.; Rangel, C. M.The development of new proton exchange membranes for PEM technology in fuel cells and electrolysers with increased durability is paramount to system's lifetime and scalability. In this work, new modified Nafion membranes are proposed with increased resilience to chemical degradation by H2O2/Fe2+, mimicking ex-situ radical attack to membrane structure.Morphological analysis by SEM revealed the formation of a het...
New modified Nafion-bisphosphonic acid composite membranes for enhanced proton ...
Teixeira, António P.S.; Teixeira, Fátima C.; Rangel, C. M.; Sá, Ana I. de; Ortiz, A.; Ortiz, I.; Ortiz-Martínez, V. M.Proton exchange membranes remain a crucial material and a key challenge to fuel cell science and technology. In this work, new Nafion membranes are prepared by a casting method using aryl- or azaheteroaromatic bisphosphonate compounds as dopants. The incorporation of the dopant, considered at 1 wt% loading after previous selection, produces enhanced proton conductivity properties in the new membranes, at differ...
Novas Membranas Condutoras de Protões para Células de Combustível
Teixeira, António P.S.; Teixeira, Fátima C.; Rangel, C. M.As membranas de permuta protónica continuam a ser um material fundamental e um desafio chave no desenvolvimento das células de combustível. Neste trabalho foram preparadas, usando um método de casting, novas membranas de Nafion dopadas com 1 wt% de diferentes ácidos bisfosfónicos (BPs). As novas membranas foram avaliadas relativamente à sua capacidade de absorção de água (water uptake), por gravimetria, à sua c...
Synthesis of novel pyrazolo[3,4-b]quinolinebisphosphonic acids and an unexpecte...
Teixeira, António P. S.; Teixeira, Fátima C.; Lucas, Carla; Curto, M. João M.; André, Vânia; Duarte, M. TeresaNovel pyrazolo[3,4-b]quinoline α-ketophosphonic and hydroxymethylenebisphosphonic acid compounds were synthesized using different methodologies, starting from 2-chloro-3-formylquinoline 1. New phosphonic acid compounds were obtained as N-1 derivatives with a side chain with 1 or 3 (n = 1 or 3) methylene groups. All phosphonic acid compounds and their corresponding ester and carboxylic acid precursors were fully ...