The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Robert F Savinell - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane Fuel Cell Applications ii methanol uptake and methanol permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct methanol Fuel Cell Applications. Methanol uptake and methanol permeability were measured in liquid and vapor phase as a function of temperature, methanol vapor activity, and silica content. Decreased methanol uptake from liquid methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %. The hybrid membrane with silica content of ≈20 wt % showed a significant lower methanol permeation rate when immersed in a liquid methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower methanol vapor permeability was seen only in the hybrid membrane with silica content of ≈20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct methanol Fuel Cells operating either on liquid or vapor-feed Fuels. © 2001 The Electrochemical Society. All rights reserved.
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evaluation of a sol gel derived nafion silica hybrid membrane for proton electrolyte membrane Fuel Cell Applications i proton conductivity and water content
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion®/silica hybrid membranes were investigated as a potential polymer electrolyte for Fuel Cell Applications. Membrane proton conductivity and water content were measured as a function of temperature, water vapor activity, and silica content. The hybrid membranes have a higher water content at 25 and 120°C, but not at 150 and 170°C. Despite the higher water content, the proton conductivities in the hybrid membranes are lower than, or equal to, that in unmodified Nafion membranes under all conditions investigated. The proton conductivity of the hybrid membrane decreases with increasing silica content under all conditions. © 2001 The Electrochemical Society. All rights reserved.
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evaluation of a sol gel derived nafion silica hybrid membrane for proton electrolyte membrane Fuel Cell Applications i proton conductivity and water content
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion®/silica hybrid membranes were investigated as a potential polymer electrolyte for Fuel Cell Applications. Membrane proton conductivity and water content were measured as a function of temperature, water vapor activity, and silica content. The hybrid membranes have a higher water content at 25 and 120°C, but not at 150 and 170°C. Despite the higher water content, the proton conductivities in the hybrid membranes are lower than, or equal to, that in unmodified Nation membranes under all conditions investigated. The proton conductivity of the hybrid membrane decreases with increasing silica content under all conditions.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane Fuel Cell Applications ii methanol uptake and methanol permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct methanol Fuel Cell Applications. Methanol uptake and methanol permeability were measured in liquid and vapor phase as a function of temperature, methanol vapor activity, and silica content. Decreased methanol uptake from liquid methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %, The hybrid membrane with silica content of 20 wt % showed a significant lower methanol permeation rate when immersed in a liquid methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower methanol vapor permeability was seen only in the hybrid membrane with silica content of 20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct methanol Fuel Cells operating either on liquid or vapor-feed Fuels.
Naoto Miyake - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane Fuel Cell Applications ii methanol uptake and methanol permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct methanol Fuel Cell Applications. Methanol uptake and methanol permeability were measured in liquid and vapor phase as a function of temperature, methanol vapor activity, and silica content. Decreased methanol uptake from liquid methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %. The hybrid membrane with silica content of ≈20 wt % showed a significant lower methanol permeation rate when immersed in a liquid methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower methanol vapor permeability was seen only in the hybrid membrane with silica content of ≈20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct methanol Fuel Cells operating either on liquid or vapor-feed Fuels. © 2001 The Electrochemical Society. All rights reserved.
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evaluation of a sol gel derived nafion silica hybrid membrane for proton electrolyte membrane Fuel Cell Applications i proton conductivity and water content
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion®/silica hybrid membranes were investigated as a potential polymer electrolyte for Fuel Cell Applications. Membrane proton conductivity and water content were measured as a function of temperature, water vapor activity, and silica content. The hybrid membranes have a higher water content at 25 and 120°C, but not at 150 and 170°C. Despite the higher water content, the proton conductivities in the hybrid membranes are lower than, or equal to, that in unmodified Nafion membranes under all conditions investigated. The proton conductivity of the hybrid membrane decreases with increasing silica content under all conditions. © 2001 The Electrochemical Society. All rights reserved.
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evaluation of a sol gel derived nafion silica hybrid membrane for proton electrolyte membrane Fuel Cell Applications i proton conductivity and water content
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion®/silica hybrid membranes were investigated as a potential polymer electrolyte for Fuel Cell Applications. Membrane proton conductivity and water content were measured as a function of temperature, water vapor activity, and silica content. The hybrid membranes have a higher water content at 25 and 120°C, but not at 150 and 170°C. Despite the higher water content, the proton conductivities in the hybrid membranes are lower than, or equal to, that in unmodified Nation membranes under all conditions investigated. The proton conductivity of the hybrid membrane decreases with increasing silica content under all conditions.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane Fuel Cell Applications ii methanol uptake and methanol permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct methanol Fuel Cell Applications. Methanol uptake and methanol permeability were measured in liquid and vapor phase as a function of temperature, methanol vapor activity, and silica content. Decreased methanol uptake from liquid methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %, The hybrid membrane with silica content of 20 wt % showed a significant lower methanol permeation rate when immersed in a liquid methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower methanol vapor permeability was seen only in the hybrid membrane with silica content of 20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct methanol Fuel Cells operating either on liquid or vapor-feed Fuels.
Jesse S Wainright - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane Fuel Cell Applications ii methanol uptake and methanol permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct methanol Fuel Cell Applications. Methanol uptake and methanol permeability were measured in liquid and vapor phase as a function of temperature, methanol vapor activity, and silica content. Decreased methanol uptake from liquid methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %. The hybrid membrane with silica content of ≈20 wt % showed a significant lower methanol permeation rate when immersed in a liquid methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower methanol vapor permeability was seen only in the hybrid membrane with silica content of ≈20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct methanol Fuel Cells operating either on liquid or vapor-feed Fuels. © 2001 The Electrochemical Society. All rights reserved.
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evaluation of a sol gel derived nafion silica hybrid membrane for proton electrolyte membrane Fuel Cell Applications i proton conductivity and water content
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion®/silica hybrid membranes were investigated as a potential polymer electrolyte for Fuel Cell Applications. Membrane proton conductivity and water content were measured as a function of temperature, water vapor activity, and silica content. The hybrid membranes have a higher water content at 25 and 120°C, but not at 150 and 170°C. Despite the higher water content, the proton conductivities in the hybrid membranes are lower than, or equal to, that in unmodified Nafion membranes under all conditions investigated. The proton conductivity of the hybrid membrane decreases with increasing silica content under all conditions. © 2001 The Electrochemical Society. All rights reserved.
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evaluation of a sol gel derived nafion silica hybrid membrane for proton electrolyte membrane Fuel Cell Applications i proton conductivity and water content
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion®/silica hybrid membranes were investigated as a potential polymer electrolyte for Fuel Cell Applications. Membrane proton conductivity and water content were measured as a function of temperature, water vapor activity, and silica content. The hybrid membranes have a higher water content at 25 and 120°C, but not at 150 and 170°C. Despite the higher water content, the proton conductivities in the hybrid membranes are lower than, or equal to, that in unmodified Nation membranes under all conditions investigated. The proton conductivity of the hybrid membrane decreases with increasing silica content under all conditions.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane Fuel Cell Applications ii methanol uptake and methanol permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct methanol Fuel Cell Applications. Methanol uptake and methanol permeability were measured in liquid and vapor phase as a function of temperature, methanol vapor activity, and silica content. Decreased methanol uptake from liquid methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %, The hybrid membrane with silica content of 20 wt % showed a significant lower methanol permeation rate when immersed in a liquid methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower methanol vapor permeability was seen only in the hybrid membrane with silica content of 20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct methanol Fuel Cells operating either on liquid or vapor-feed Fuels.
Jiujun Zhang - One of the best experts on this subject based on the ideXlab platform.
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alkaline polymer electrolyte membranes for Fuel Cell Applications
Chemical Society Reviews, 2013Co-Authors: Yanjie Wang, Jinli Qiao, Ryan Baker, Jiujun ZhangAbstract:In this review, we examine the most recent progress and research trends in the area of alkaline polymer electrolyte membrane (PEM) development in terms of material selection, synthesis, characterization, and theoretical approach, as well as their fabrication into alkaline PEM-based membrane electrode assemblies (MEAs) and the corresponding performance/durability in alkaline polymer electrolyte membrane Fuel Cells (PEMFCs). Respective advantages and challenges are also reviewed. To overcome challenges hindering alkaline PEM technology advancement and commercialization, several research directions are then proposed.
Wan Ramli Wan Daud - One of the best experts on this subject based on the ideXlab platform.
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additives in proton exchange membranes for low and high temperature Fuel Cell Applications a review
International Journal of Hydrogen Energy, 2019Co-Authors: Chun Yik Wong, Wai Yin Wong, K Ramya, Mohammad Khalid, Kee Shyuan Loh, Wan Ramli Wan Daud, Kean Long Lim, Rashmi Walvekar, Abdul Amir H KadhumAbstract:Abstract Polymer electrolyte membranes, also known as proton exchange membranes (PEMs), are a type of semipermeable membrane that exhibits the property of conducting ions while impeding the mixing of reactant materials across the membrane. Due to the large potential and substantial number of Applications of these materials, the development of proton exchange membranes (PEMs) has been in progress for the last few decades to successfully replace the commercial Nafion® membranes. In the course of this research, an alternate perspective of PEMs has been initiated with a desire to attain successful operations at higher working temperatures (120–200 °C) while retaining the physical properties, stability and high proton conductivity. Both low- and high-temperature PEMs have been fabricated by various processes, such as grafting, cross-linking, or combining polymer electrolytes with nanoparticles, additives and acid-base complexes by electrostatic interactions, or by employing layer-by-layer technologies. The current review suggests that the incorporation of additives such as plasticisers and fillers has proven potential to modify the physical and chemical properties of pristine and/or composite membranes. In many studies, additives have demonstrated a substantial role in ameliorating both the mechanical and electrical properties of PEMs to make them effective for Fuel Cell Applications. It is notable that plasticiser additives are less desirable for the development of high-temperature PEMs, as their inherent highly hydrophilic properties may stiffen the membrane. Conversely, filler additives form an inorganic-organic composite with increased surface area to retain more bound water within the polymer matrices to overcome the drawbacks of ohmic losses at high operating temperatures.
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recent progress in nitrogen doped carbon and its composites as electrocatalysts for Fuel Cell Applications
International Journal of Hydrogen Energy, 2013Co-Authors: Wai Yin Wong, Kee Shyuan Loh, Wan Ramli Wan Daud, Abdul Amir H Kadhum, Abu Bakar Mohamad, Edy Herianto MajlanAbstract:Abstract The emergence of Fuel Cell technology has created a new tool for the generation of clean, high efficiency alternative energy for humans. The research and development of new catalysts to replace the expensive and rare platinum (Pt) to reduce the overall cost of Fuel Cells is ongoing in this area. Nitrogen-doped carbon and its composites possess great potential for Fuel Cell catalyst Applications especially at the oxygen reduction cathode. It is proposed that the reaction mechanisms of nitrogen-doped carbon catalysts for oxygen reduction involve adsorption of oxygen at the partially polarised carbon atoms adjacent to the nitrogen dopants, different from the mechanism at platinum catalysts, which utilise d-bands filling at oxygen adsorption sites. Nitrogen doping in both carbon nanostructures and its composites with active metals or ceramics are reviewed. Nitrogen-doped carbon without composite metals, displays high catalytic activity in alkaline Fuel Cells and exhibits significant activity in proton exchange membrane Fuel Cells and direct methanol Fuel Cells. Pt-based catalysts with nitrogen-doped carbon supports show enhanced catalytic activity towards oxygen reduction, attributed to the enhanced anchoring of Pt to the support that results in better dispersion and stability of the electrodes. For nitrogen-doped carbon composites with non-noble metals (Fe, Co, etc), enhanced activity is seen in both proton exchange and alkaline Fuel Cells. There are many ongoing debates about the nature of nitrogen-carbon bond in catalysis. Pyrrole- and pyridinic-type nitrogen generally considered to be responsible for the catalytic sites in acidic and alkaline media, respectively. In recent years, significant efforts have been made towards increasing the stability of nitrogen-doped carbon catalysts in acidic media through the formation of composites with ceramic or metal oxide materials. This article reviews the progress in the area of this new class of catalysts and their composites for greater enhancement of oxygen reduction activity and stability in various Fuel Cell Applications.
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overview of hybrid membranes for direct methanol Fuel Cell Applications
International Journal of Hydrogen Energy, 2010Co-Authors: H Ahmad, Siti Kartom Kamarudin, U A Hasran, Wan Ramli Wan DaudAbstract:Abstract The direct-methanol Fuel Cell (DMFC), a type of polymer-electrolyte membrane Fuel Cell, has lately received much attention because of its potential applicability as a good alternative power source for the future. In order to achieve commercially viable performance goals for the DMFC, a membrane with several important selective behaviors will need to be developed. Over roughly the past four decades, researchers have used the commercial Nafion membrane by DuPont as a proton-conductive membrane in DMFCs due to its chemical stability and high proton conductivity, as well as high mechanical strength. However, Nafion membranes also have several weaknesses such as high methanol permeability and an operational temperature limited to ∼100 °C or lower, and Nafion is also a very expensive material. Besides Nafion, there have been several engineering thermoplastic polymers such as poly(etheretherketone) (PEEK), polysulfone (PSF) and polybenzimidazole (PBI) used as alternative membranes due to their lower cost and very high mechanical and thermal stability in high temperature operation. To date, there has been continuous extensive research on developing a membrane which can fulfill all of the essential characteristics to yield the desired performance in DMFCs. In the course of this research, hybrid membranes have been developed by modifying the original membranes to produce new membranes with variously enhanced properties. This review discusses recent advances in hybrid membranes of two main types: Nafion-based and non-Nafion-based membranes. Recent achievements and prospect of Applications also been included in this paper.
