The Experts below are selected from a list of 6903 Experts worldwide ranked by ideXlab platform
Risto M. Nieminen - One of the best experts on this subject based on the ideXlab platform.
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doped graphene as a material for oxygen reduction reaction in Hydrogen Fuel Cells a computational study
ACS Catalysis, 2013Co-Authors: Maria Kaukonen, Esko Kauppinen, Arkady V. Krasheninnikov, Risto M. NieminenAbstract:Because of its high specific surface area and unique electronic properties, graphene with substitutional impurity metal atoms and clusters attached to defects in the graphene sheet is attractive for use in Hydrogen Fuel Cells for oxygen reduction at the cathode. In an attempt to find a cheap yet efficient catalyst for the reaction, we use density-functional theory calculations to study the structure and properties of transition-metal-vacancy complexes in graphene. We calculate formation energies of the complexes, which are directly related to their stability, along with oxygen and water adsorption energies. In addition to metals, we also consider nonmetal impurities like B, P, and Si, which form strong bonds with under-coordinated carbon atoms at defects in graphene. Our results indicate that single Ni, Pd, Pt, Sn, and P atoms embedded into divacancies in graphene are promising candidates for the use in Fuel cell cathodes for oxygen reduction reaction (ORR). We further discuss how ion irradiation of graph...
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Doped graphene as a material for oxygen reduction reaction in Hydrogen Fuel Cells: A computational study
ACS Catalysis, 2013Co-Authors: Maria Kaukonen, Esko Kauppinen, Arkady V. Krasheninnikov, Risto M. NieminenAbstract:Because of its high specific surface area and unique electronic properties, graphene with substitutional impurity metal atoms and clusters attached to defects in the graphene sheet is attractive for use in Hydrogen Fuel Cells for oxygen reduction at the cathode. In an attempt to find a cheap yet efficient catalyst for the reaction, we use density-functional theory calculations to study the structure and properties of transition-metal-vacancy complexes in graphene. We calculate formation energies of the complexes, which are directly related to their stability, along with oxygen and water adsorption energies. In addition to metals, we also consider nonmetal impurities like B, P, and Si, which form strong bonds with under-coordinated carbon atoms at defects in graphene. Our results indicate that single Ni, Pd, Pt, Sn, and P atoms embedded into divacancies in graphene are promising candidates for the use in Fuel cell cathodes for oxygen reduction reaction (ORR). We further discuss how ion irradiation of graphene combined with metal sputtering and codeposition can be used to make an efficient and relatively inexpensive graphene-based material for Hydrogen Fuel Cells.
Ottorino Veneri - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen Fuel Cells for Road Vehicles
Hydrogen Fuel Cells for Road Vehicles, 2011Co-Authors: Pasquale Corbo, Fortunato Migliardini, Ottorino VeneriAbstract:In recent years the concept of a Fuel cell propulsion system has gained in attention\r\nas a result of the need to reduce the fossil Fuel consumption and greenhouse gas\r\nemissions. Since the Fuel Cells suitable for vehicle application (polymeric electrolyte\r\nmembrane Fuel Cells) are Fuelled by Hydrogen, and deliver power as long as\r\nFuel and air are supplied, they potentially can provide the range capabilities of an\r\ninternal combustion engine when used in a power system, but with clean and quiet\r\noperation. Therefore, the fundamental benefit of this type of propulsion consists in\r\nthe possibility to adopt pollution-free electric drive-trains, without the drive range\r\nlimitations typical of traditional electric vehicles.\r\nA Fuel cell propulsion system operates in hybrid configuration with an electric\r\nenergy storage system (batteries and/or supercapacitors), in order to take advantage\r\nof the best attributes of both power sources. In fact, against the driving range\r\ncapabilities of Fuel Cells, batteries and supercapacitors are characterized by defined\r\nand limited energy storage, but are able to deliver large peak current without the\r\nlimitations due to the dynamic behavior of auxiliary sub-systems of the Fuel cell\r\ngenerator. Fuel Cells and storage systems, therefore, complement each other in a\r\nhybrid configuration where they supply the electric drive through an electric\r\nparallel connection. Suitable management strategies have to be implemented to\r\noptimize the energy flows within the overall power train, as function of power size\r\nand road mission of the vehicle, with the goal of achieving peak acceleration\r\npower, long range and recharge capabilities.\r\nThis book is organized to provide a general view of the present status of this\r\nmoving field, taking into account that the study of a propulsion system using\r\nHydrogen as a Fuel, an electric drive train for traction and electrochemical systems\r\nas power sources requires some basic knowledge in different scientific disciplines.\r\nThe text is aimed at undergraduate or graduate-level students, and has been\r\nstructured in a theoretical part, dealing with the fundamental concepts involved in\r\nthe study of a Fuel cell power train, and in a final practical section where the\r\nprinciples previously illustrated are applied in design, realization and experimental\r\ncharacterization of two real Fuel cell propulsion systems.
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Hydrogen Fuel Cells for Road Vehicles (Green Energy and Technology)
Amazon, 2011Co-Authors: Pasquale Corbo, Fortunato Migliardini, Ottorino VeneriAbstract:Hydrogen Fuel Cells for Road Vehicles addresses the main issues related to the application of Hydrogen Fuel cell technology in the road transportation sector. A preliminary treatment is given on Fuel resources and atmospheric pollution concerns which are closely related to the current technology (internal combustion engine) used for moving people and goods. The authors deal, in particular, with the problems that can hinder a widespread Hydrogen market (production, storage and distribution), as well as giving an analysis of Fuel cell technologies available for utilization of this energy carrier in the automotive field. Hydrogen Fuel Cells for Road Vehicles also examines the concerns faced during the design and realization of a PEM Fuel cell system with optimal size and efficiency, evidencing the impact of the individual auxiliary components on energy losses and dynamic stack performance. The book ends with the analysis of two practical case studies on Fuel cell propulsion systems. Hydrogen Fuel Cells for Road Vehicles is a useful text for researchers, professionals and advanced students in the fields of automotive and environmental engineering.
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dynamic behaviour of Hydrogen Fuel Cells for automotive application
Renewable Energy, 2009Co-Authors: Pasquale Corbo, Fortunato Migliardini, Ottorino VeneriAbstract:An experimental analysis was conducted on a 30kW Fuel cell power train with the aim to elucidate specific concerns of dynamic behaviour of Hydrogen Fuel Cells in automotive applications. The study was conducted on a dynamic test bench able to simulate the behaviour of the reference vehicle, a minibus for historical centres collective service, on predefined driving cycle. The transient performance of the Fuel cell system was firstly investigated without electric drive, using as load electric resistances electronically controlled. Experimental data were collected during warmup phases characterized by two acceleration slopes (150W/s and 1500W/s) and during a sequence of dynamic test cycles characterized by a very high acceleration slope of about 6kW/s. The role of reactant feeding, humidification and cooling systems was investigated during all tests evaluating the performance during the transient steps in terms of cell voltage uniformity, expressed by the coefficient of variation Cv, used as statistical indicator. A driving cycle characterized by stop-and-go pattern and acceleration slopes compatible with a real utilization of the reference vehicle was finally adopted for tests on the overall power train. The results demonstrated a very good dynamic performance of the Fuel cell stack as evidenced by the analysis of Cv, which resulted lower than 2.5% in all investigated working conditions, and by the overall power train efficiency which resulted about 30% with Fuel cell system efficiency close to 50%.
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Dynamic behaviour of Hydrogen Fuel Cells for automotive application
Renewable Energy, 2009Co-Authors: Pasquale Corbo, Fortunato Migliardini, Ottorino VeneriAbstract:An experimental analysis was conducted on a 30 kW Fuel cell power train with the aim to elucidate specific concerns of dynamic behaviour of Hydrogen Fuel Cells in automotive applications. The study was conducted on a dynamic test bench able to simulate the behaviour of the reference vehicle, a minibus for historical centres collective service, on predefined driving cycle. The transient performance of the Fuel cell system was firstly investigated without electric drive, using as load electric resistances electronically controlled. Experimental data were collected during warmup phases characterized by two acceleration slopes (150 W/s and 1500 W/s) and during a sequence of dynamic test cycles characterized by a very high acceleration slope of about 6 kW/s. The role of reactant feeding, humidification and cooling systems was investigated during all tests evaluating the performance during the transient steps in terms of cell voltage uniformity, expressed by the coefficient of variation Cv, used as statistical indicator. A driving cycle characterized by stop-and-go pattern and acceleration slopes compatible with a real utilization of the reference vehicle was finally adopted for tests on the overall power train. The results demonstrated a very good dynamic performance of the Fuel cell stack as evidenced by the analysis of Cv, which resulted lower than 2.5% in all investigated working conditions, and by the overall power train efficiency which resulted about 30% with Fuel cell system efficiency close to 50%. © 2008 Elsevier Ltd. All rights reserved.
Fraser A. Armstrong - One of the best experts on this subject based on the ideXlab platform.
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pushing the limits for enzyme based membrane less Hydrogen Fuel Cells achieving useful power and stability
RSC Advances, 2015Co-Authors: Lang Xu, Fraser A. ArmstrongAbstract:The performance characteristics of simple enzyme-based membrane-less Hydrogen Fuel Cells running on non-explosive H2-rich air mixtures have been established using an adjustable test bed that allows multiple unit Cells to operate in series or parallel. Recent advances with ‘3D’ electrodes constructed from compacted porous carbon loaded with Hydrogenase (anode) and bilirubin oxidase (cathode) have been extended in order to scale up Fuel cell power to useful levels. One result is an appealing ‘classroom’ demonstration of a model house containing small electronic devices powered by H2 mixed with a small amount of air. The 3D electrodes work by greatly increasing catalyst loading (at both the anode and cathode) and selectively restricting the access of O2 (relative to H2) to enzymes embedded in pores at the anode. The latter property raises the possibility of using standard Hydrogenases that are not O2-tolerant: however, experiments with such an enzyme reveal good short-term performance due to restricted O2 access, but low long-term stability because the root cause of O2 sensitivity has not been addressed. Hydrogenases that are truly O2 tolerant must therefore remain the major focus of any future enzyme-based Hydrogen Fuel cell technology.
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characteristics of enzyme based Hydrogen Fuel Cells using an oxygen tolerant Hydrogenase as the anodic catalyst
Journal of Physical Chemistry C, 2010Co-Authors: Annemarie F. Wait, Gregory M. Morley, Alison Parkin, Luciano Dos Santos, Fraser A. ArmstrongAbstract:The special properties of O2-tolerant [NiFe]-Hydrogenases make it possible, in principle, to operate all-enzyme Hydrogen Fuel Cells. These devices show unusual power characteristics, as revealed in a series of experiments in which the O2-tolerant Hydrogenase (Hyd-1) from Escherichia coli is used as H2-oxidation catalyst (anode) and a bilirubin oxidase is used as O2-reduction catalyst (cathode). In a Fuel cell adaptable for variable Fuel and oxidant supply, three limiting conditions were examined: (1) the anode and cathode separated by a Nafion membrane and 100% H2 and 100% O2 fed to the separate compartments, (2) a membrane-free mixed feed cell with a Fuel-rich (96% H2) Hydrogen/oxygen mixture, and (3) a membrane-free mixed feed cell with a Fuel-weak (4% H2) Hydrogen/air mixture. Condition (1) exposes the effect of O2-crossover which is evident even for an O2-tolerant Hydrogenase, whereas condition (2) is limited by bilirubin oxidase activity on the cathode. Condition (3) yields power only under high-load...
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Characteristics of enzyme-based Hydrogen Fuel Cells using an oxygen-tolerant Hydrogenase as the anodic catalyst
Journal of Physical Chemistry C, 2010Co-Authors: Annemarie F. Wait, Gregory M. Morley, Luciano Dos Santos, Andrew Parkin, Fraser A. ArmstrongAbstract:The special properties of O2-tolerant NiFe-Hydrogenases make it possible, in principle, to operate all-enzyme Hydrogen Fuel Cells. These devices show unusual power characteristics, as revealed in a series of experiments in which the O2-tolerant Hydrogenase (Hyd-1) from Escherichia coli is used as H2-oxidation catalyst (anode) and a bilirubin oxidase is used as O2-reduction catalyst (cathode). In a Fuel cell adaptable for variable Fuel and oxidant supply, three limiting conditions were examined: (1) the anode and cathode separated by a Nafion membrane and 100% H2 and 100% O2 fed to the separate compartments, (2) a membrane-free mixed feed cell with a Fuel-rich (96% H2) Hydrogen/oxygen mixture, and (3) a membrane-free mixed feed cell with a Fuel-weak (4% H2) Hydrogen/air mixture. Condition (1) exposes the effect of O2-crossover which is evident even for an O2-tolerant Hydrogenase, whereas condition (2) is limited by bilirubin oxidase activity on the cathode. Condition (3) yields power only under high-load (resistance) conditions that maintain a high output voltage; a low load collapses the power (akin to a circuit breaker) because of complete inactivation of the NiFe-Hydrogenase when subjected to O2 at high potential. Recovery of the Hydrogen-poor Fuel cell is not achieved simply by restoring the high load but by briefly connecting a second anode containing active Hydrogenase which discharges electrons to provide a jump start. The second anode had remained active despite being in the same O2 environment because it was not electrochemically connected to an oxidizing source (the cathode), thus demonstrating that, under 4% H2, the presence of 20% O2 does not, alone, cause Hydrogenase inactivation, but simultaneous connection to an oxidizing potential is also required. The investigation helps to illuminate obstacles to the application of Hydrogenases in Fuel-cell technology and suggests phenomena that might be relevant for biology where biological membranes are engaged in H2 oxidation under aerobic conditions.
Maria Kaukonen - One of the best experts on this subject based on the ideXlab platform.
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doped graphene as a material for oxygen reduction reaction in Hydrogen Fuel Cells a computational study
ACS Catalysis, 2013Co-Authors: Maria Kaukonen, Esko Kauppinen, Arkady V. Krasheninnikov, Risto M. NieminenAbstract:Because of its high specific surface area and unique electronic properties, graphene with substitutional impurity metal atoms and clusters attached to defects in the graphene sheet is attractive for use in Hydrogen Fuel Cells for oxygen reduction at the cathode. In an attempt to find a cheap yet efficient catalyst for the reaction, we use density-functional theory calculations to study the structure and properties of transition-metal-vacancy complexes in graphene. We calculate formation energies of the complexes, which are directly related to their stability, along with oxygen and water adsorption energies. In addition to metals, we also consider nonmetal impurities like B, P, and Si, which form strong bonds with under-coordinated carbon atoms at defects in graphene. Our results indicate that single Ni, Pd, Pt, Sn, and P atoms embedded into divacancies in graphene are promising candidates for the use in Fuel cell cathodes for oxygen reduction reaction (ORR). We further discuss how ion irradiation of graph...
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Doped graphene as a material for oxygen reduction reaction in Hydrogen Fuel Cells: A computational study
ACS Catalysis, 2013Co-Authors: Maria Kaukonen, Esko Kauppinen, Arkady V. Krasheninnikov, Risto M. NieminenAbstract:Because of its high specific surface area and unique electronic properties, graphene with substitutional impurity metal atoms and clusters attached to defects in the graphene sheet is attractive for use in Hydrogen Fuel Cells for oxygen reduction at the cathode. In an attempt to find a cheap yet efficient catalyst for the reaction, we use density-functional theory calculations to study the structure and properties of transition-metal-vacancy complexes in graphene. We calculate formation energies of the complexes, which are directly related to their stability, along with oxygen and water adsorption energies. In addition to metals, we also consider nonmetal impurities like B, P, and Si, which form strong bonds with under-coordinated carbon atoms at defects in graphene. Our results indicate that single Ni, Pd, Pt, Sn, and P atoms embedded into divacancies in graphene are promising candidates for the use in Fuel cell cathodes for oxygen reduction reaction (ORR). We further discuss how ion irradiation of graphene combined with metal sputtering and codeposition can be used to make an efficient and relatively inexpensive graphene-based material for Hydrogen Fuel Cells.
Pasquale Corbo - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen Fuel Cells for Road Vehicles
Hydrogen Fuel Cells for Road Vehicles, 2011Co-Authors: Pasquale Corbo, Fortunato Migliardini, Ottorino VeneriAbstract:In recent years the concept of a Fuel cell propulsion system has gained in attention\r\nas a result of the need to reduce the fossil Fuel consumption and greenhouse gas\r\nemissions. Since the Fuel Cells suitable for vehicle application (polymeric electrolyte\r\nmembrane Fuel Cells) are Fuelled by Hydrogen, and deliver power as long as\r\nFuel and air are supplied, they potentially can provide the range capabilities of an\r\ninternal combustion engine when used in a power system, but with clean and quiet\r\noperation. Therefore, the fundamental benefit of this type of propulsion consists in\r\nthe possibility to adopt pollution-free electric drive-trains, without the drive range\r\nlimitations typical of traditional electric vehicles.\r\nA Fuel cell propulsion system operates in hybrid configuration with an electric\r\nenergy storage system (batteries and/or supercapacitors), in order to take advantage\r\nof the best attributes of both power sources. In fact, against the driving range\r\ncapabilities of Fuel Cells, batteries and supercapacitors are characterized by defined\r\nand limited energy storage, but are able to deliver large peak current without the\r\nlimitations due to the dynamic behavior of auxiliary sub-systems of the Fuel cell\r\ngenerator. Fuel Cells and storage systems, therefore, complement each other in a\r\nhybrid configuration where they supply the electric drive through an electric\r\nparallel connection. Suitable management strategies have to be implemented to\r\noptimize the energy flows within the overall power train, as function of power size\r\nand road mission of the vehicle, with the goal of achieving peak acceleration\r\npower, long range and recharge capabilities.\r\nThis book is organized to provide a general view of the present status of this\r\nmoving field, taking into account that the study of a propulsion system using\r\nHydrogen as a Fuel, an electric drive train for traction and electrochemical systems\r\nas power sources requires some basic knowledge in different scientific disciplines.\r\nThe text is aimed at undergraduate or graduate-level students, and has been\r\nstructured in a theoretical part, dealing with the fundamental concepts involved in\r\nthe study of a Fuel cell power train, and in a final practical section where the\r\nprinciples previously illustrated are applied in design, realization and experimental\r\ncharacterization of two real Fuel cell propulsion systems.
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Hydrogen Fuel Cells for Road Vehicles (Green Energy and Technology)
Amazon, 2011Co-Authors: Pasquale Corbo, Fortunato Migliardini, Ottorino VeneriAbstract:Hydrogen Fuel Cells for Road Vehicles addresses the main issues related to the application of Hydrogen Fuel cell technology in the road transportation sector. A preliminary treatment is given on Fuel resources and atmospheric pollution concerns which are closely related to the current technology (internal combustion engine) used for moving people and goods. The authors deal, in particular, with the problems that can hinder a widespread Hydrogen market (production, storage and distribution), as well as giving an analysis of Fuel cell technologies available for utilization of this energy carrier in the automotive field. Hydrogen Fuel Cells for Road Vehicles also examines the concerns faced during the design and realization of a PEM Fuel cell system with optimal size and efficiency, evidencing the impact of the individual auxiliary components on energy losses and dynamic stack performance. The book ends with the analysis of two practical case studies on Fuel cell propulsion systems. Hydrogen Fuel Cells for Road Vehicles is a useful text for researchers, professionals and advanced students in the fields of automotive and environmental engineering.
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dynamic behaviour of Hydrogen Fuel Cells for automotive application
Renewable Energy, 2009Co-Authors: Pasquale Corbo, Fortunato Migliardini, Ottorino VeneriAbstract:An experimental analysis was conducted on a 30kW Fuel cell power train with the aim to elucidate specific concerns of dynamic behaviour of Hydrogen Fuel Cells in automotive applications. The study was conducted on a dynamic test bench able to simulate the behaviour of the reference vehicle, a minibus for historical centres collective service, on predefined driving cycle. The transient performance of the Fuel cell system was firstly investigated without electric drive, using as load electric resistances electronically controlled. Experimental data were collected during warmup phases characterized by two acceleration slopes (150W/s and 1500W/s) and during a sequence of dynamic test cycles characterized by a very high acceleration slope of about 6kW/s. The role of reactant feeding, humidification and cooling systems was investigated during all tests evaluating the performance during the transient steps in terms of cell voltage uniformity, expressed by the coefficient of variation Cv, used as statistical indicator. A driving cycle characterized by stop-and-go pattern and acceleration slopes compatible with a real utilization of the reference vehicle was finally adopted for tests on the overall power train. The results demonstrated a very good dynamic performance of the Fuel cell stack as evidenced by the analysis of Cv, which resulted lower than 2.5% in all investigated working conditions, and by the overall power train efficiency which resulted about 30% with Fuel cell system efficiency close to 50%.
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Dynamic behaviour of Hydrogen Fuel Cells for automotive application
Renewable Energy, 2009Co-Authors: Pasquale Corbo, Fortunato Migliardini, Ottorino VeneriAbstract:An experimental analysis was conducted on a 30 kW Fuel cell power train with the aim to elucidate specific concerns of dynamic behaviour of Hydrogen Fuel Cells in automotive applications. The study was conducted on a dynamic test bench able to simulate the behaviour of the reference vehicle, a minibus for historical centres collective service, on predefined driving cycle. The transient performance of the Fuel cell system was firstly investigated without electric drive, using as load electric resistances electronically controlled. Experimental data were collected during warmup phases characterized by two acceleration slopes (150 W/s and 1500 W/s) and during a sequence of dynamic test cycles characterized by a very high acceleration slope of about 6 kW/s. The role of reactant feeding, humidification and cooling systems was investigated during all tests evaluating the performance during the transient steps in terms of cell voltage uniformity, expressed by the coefficient of variation Cv, used as statistical indicator. A driving cycle characterized by stop-and-go pattern and acceleration slopes compatible with a real utilization of the reference vehicle was finally adopted for tests on the overall power train. The results demonstrated a very good dynamic performance of the Fuel cell stack as evidenced by the analysis of Cv, which resulted lower than 2.5% in all investigated working conditions, and by the overall power train efficiency which resulted about 30% with Fuel cell system efficiency close to 50%. © 2008 Elsevier Ltd. All rights reserved.
