Uma Thanganathan
Abstract
A class of proton-conducting non-fluorinated hybrid composite membranes was produced based on poly(vinylpyrrolidone)-doped tetraethoxysilicate (TEOS) and triammoniumphosphate ((NH4)3PO4.3H2O) with and without phosphoricacid. The formation of hybrid composites was verified by various analyses, such as ...
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A class of proton-conducting non-fluorinated hybrid composite membranes was produced based on poly(vinylpyrrolidone)-doped tetraethoxysilicate (TEOS) and triammoniumphosphate ((NH4)3PO4.3H2O) with and without phosphoricacid. The formation of hybrid composites was verified by various analyses, such as XRD and 1 H NMR, and the thermal degradation was determined by thermogravimetric analysis. The proton conductivity was measured using impedance spectroscopy and values of 3.4 × 10 ‒2 S/cm and 2.3 × 10 ‒2 S/cm were obtained at room temperature for the SiO2/P2O5/(NH4)3PO4/PVP (90/8/2 mol%/1g) and the SiO2/(NH4)3PO4/PVP (90/10 mol%/1g) hybrid composite membranes, respectively. The results were discussed based on the effects of P2O5 and (NH4)3PO4 on the hybrid composites.
Giulia Ognibene; Gianluca Cicala; Maria Elena Fragalà
Abstract
ZnO nanorods (ZnO) are grown by Chemical Bath Deposition on microfiltration polyetheresulphone (PES) water membranes in order to combine photocatalytic properties of zinc oxide to adsorption properties of membranes. Degradation of a model dye (methylene blue, MB) dispersed in water is promoted by exposition ...
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ZnO nanorods (ZnO) are grown by Chemical Bath Deposition on microfiltration polyetheresulphone (PES) water membranes in order to combine photocatalytic properties of zinc oxide to adsorption properties of membranes. Degradation of a model dye (methylene blue, MB) dispersed in water is promoted by exposition of multifunctional ZnO/PES membranes to UV and solar light: in fact, ZnO decorated membrane ensures generation of reactive oxygen species (ROS) that degrade the organic pollutants dispersed in water. ZnO degradation promoted by UV irradiation is detectable by anionic meso-tetrakis(4-sulfonatophenyl) porphyrin (H2TPPS 4- ) that is used as effective molecular probe to sense the presence of Zn 2+ ions due to photocatalytic leaching. Copyright © VBRI Press.
Franco D.R. Amado;Satheesh Krishnamurthy
Abstract
Over the past decade or so, alternative energy plays a pivotal role in addressing challenges posed by nature. Polymer electrolyte membrane fuel cell is one of the promising alternative energy and there has been significant research and technological investments done in this field. The key information ...
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Over the past decade or so, alternative energy plays a pivotal role in addressing challenges posed by nature. Polymer electrolyte membrane fuel cell is one of the promising alternative energy and there has been significant research and technological investments done in this field. The key information and future prospective of the field is energy conversion and storage, both of which are essential in order to meet the challenges of global warming and the limited fossil fuel supply. However, polymer membrane in particular plays a crucial role in advancing this technology further. The utilization of conducting polymers in manufacturing membranes combining their electrochemical properties along with mechanical properties is of primary importance to enhance the efficiency of this system. In the present study blends of high impact polystyrene (HIPS) and polyaniline (PAni) were obtained with the aim of producing membranes for fuel cell. HIPS and PAni were dissolved in tetrachloroethylene, a common solvent for both materials. After dissolution, PAni was dispersed in an HIPS polymeric matrix. The membranes were molded on to glass plates using a laminator to keep thickness constant, and the solvent evaporated slowly for 24 h under room temperature. The amount of polyaniline used was 10 and 20 % weight. The electronic and structural properties were carried out using X-ray photoelectron spectroscopy (XPS), Thermogravimetric Analysis (TGA) Raman spectroscopy, Scanning electronic microscopic (SEM). The analysis indicate that PAni incorporation and its dispersion into the polymeric matrix modifies the membranes properties and show improvement in efficiency.
Omkar S. Kushwaha; C. V. Avadhani; R. P. Singh
Abstract
High temperature polymer electrolyte membrane fuel cells (HTPEMFCs) are energy efficient systems with the potential to address all energy issues of present and future generations. Polybenzimidazole (PBI) based high temperature fuel cells are subject of high importance because PBI membranes are proved ...
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High temperature polymer electrolyte membrane fuel cells (HTPEMFCs) are energy efficient systems with the potential to address all energy issues of present and future generations. Polybenzimidazole (PBI) based high temperature fuel cells are subject of high importance because PBI membranes are proved to be one of the best candidates for high temperature fuel cell applications. The stability of PBI membranes has been identified as crucial issue for the long-term durability under oxidative conditions of fuel cells. The present investigation highlights the photo-oxidative degradation studies accomplished on polybenzimidazole based poly(2,2'-butylene-5,5'-bibenzimidazole) (PBIB) membranes. The PBIB polymer membranes are found suitable for both in high temperature fuel cells as well as other high temperature applications. In this research article, PBIB membranes were photoirradiated under polychromatic UV rays (λ > 290 nm). The photo-oxidative degradation of membranes was characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM). FT-IR results showed significant amount of photo-oxidation and chemical degradation in fuel cell membranes which is proposed to be initiated by free radical mechanism. SEM images revealed development of nano-dimensional cracks and holes on surface of membranes which indicate structural and morphological degradation. The present study showed better results of accelerated photo-degradation as compared to the oxidative degradation results already reported in literature obtained chemically and thermally. Hence, the proposed photo-oxidative degradation method may be useful in determining stability, life time expectancy and degradation mechanism of fuel cell and other high performance membranes.