The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Detlef Stolten - One of the best experts on this subject based on the ideXlab platform.
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(Invited) Alkaline Water Electrolysis: Achieving High Current Densities
ECS Meeting Abstracts, 2016Co-Authors: Marcelo Carmo, Fabian Tigges, Paul Paciok, Wiebke Lüke, Detlef StoltenAbstract:The production of hydrogen via Water Electrolysis is currently recognized as the only option to store gigawatt electrical energy coming from renewable energy sources such as wind and sunlight. However, commercially available alkaline electrolyzers are still limited to low current densities (around 0.5 Acm-2), primarily due to its internal resistance losses. In order to reach the excellent current densities of acidic polymer electrolyte membrane (PEM) Water Electrolysis (ranging between 2 and 4 Acm-2), it is crucial to tailor electrolyte construction and cell design in order to overcome the high ohmic losses of conventional diaphragms and archaic cell designs used in alkaline Electrolysis. Here, we demonstrate for the first time alkaline Electrolysis achieving current densities as high as 2 A.cm-2 at 2 volts, not only well overcoming the performances of lab-scale and commercial alkaline electrolyzers, but also closely matching the performance of state-of-the-art PEM Water Electrolysis.
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High-pressure Water Electrolysis: Electrochemical mitigation of product gas crossover
Electrochimica Acta, 2015Co-Authors: Maximilian Schalenbach, Detlef StoltenAbstract:Hydrogen produced by Water Electrolysis can be used as an energy carrier storing electricity generated from renewables. During Water Electrolysis hydrogen can be evolved under pressure at isothermal conditions, enabling highly efficient compression. However, the permeation of hydrogen through the electrolyte increases with operating pressure and leads to efficiency loss and safety hazards. In this study, we report on an innovative concept, where the hydrogen crossover is electrochemically mitigated by an additional electrode between the anode and the cathode of the Electrolysis cell. Experimentally, the technique was applied to a proton exchange membrane Water electrolyzer operated at a hydrogen pressure that was fifty times larger than the oxygen pressure. Therewith, the hydrogen crossover was reduced and the current efficiency during partial load operation was increased. The concept is also discussed for Water Electrolysis that is operated at balanced pressures, where the crossover of hydrogen and oxygen is mitigated using two additional electrodes.
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Validation and characterization of suitable materials for bipolar plates in PEM Water Electrolysis
International Journal of Hydrogen Energy, 2015Co-Authors: Manuel Langemann, David Fritz, Martin Müller, Detlef StoltenAbstract:Abstract The polymer electrolyte membrane (PEM) Electrolysis cell is a promising prospect for the production of clean hydrogen by energy of renewable wind and solar sources. One component of the PEM electrolyzer is the bipolar plate (BPP), which serves as a multi-function component during PEM Water Electrolysis. Titanium is typically regarded as the state-of-the-art material. Mechanically it could potentially be replace by lower-cost materials such as stainless steel, but under the harsh environmental conditions present in PEM Water Electrolysis, stainless steel is not corrosion-resistant and metal ions can dissolve. In this case metal ions would poison the catalyst and membrane, which leads to a reduction in the cell performance [1] . We have tested several coatings such as Au and TiN in PEM Water Electrolysis environments of varying severity for the application as a protective layer of bipolar plates. In order to determine possible candidates for a long-term test under real simulated PEM Water Electrolysis conditions, an experiment to determine pH value in PEM Water Electrolysis operation was developed to obtain the required pH value for the ex-situ testing of various coating materials.
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Polymer Electrolyte Membrane (PEM) Water Electrolysis
2010Co-Authors: Tom Smolinka, Sebastian Rau, Christopher Hebling, Thomas Grube, Detlef StoltenAbstract:Water Electrolysis represents one of the simplest approaches to produce hydrogen and oxygen in a zero-pollution process by using electricity for the electrochemical decomposition of Water. In Polymer Electrolyte Membrane (PEM) Electrolysis cells, an acidic ionomer is used as the electrolyte. During the past decade, considerable progress has been made to advance this technology. Today, PEM electrolyzers can be regarded as a well-established industrial technology and are close to broader commercialization. An overview of the technical implementation of PEM Water Electrolysis is given in this chapter. Efficiency values and a selection of materials will be presented for a single cell and at the stack level. Lifetimes and degradation mechanisms will be considered. Finally, production rates and the power consumption for the system will be discussed. Copyright Stolten, D. (Ed.): Hydrogen and Fuel Cells Fundamentals, Technologies and Applications. Chapter 13. 2010. Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission. Proceedings WHEC2010 131
Ming Chang - One of the best experts on this subject based on the ideXlab platform.
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Fabrication of TiO2 film with different morphologies on Ni anode and application in photoassisted Water Electrolysis
Applied Surface Science, 2013Co-Authors: Aiping Chen, Haijun Dong, Ming ChangAbstract:Abstract The anode of an alkaline electrolytic cell for Water Electrolysis was modified by TiO2 photocatalysts with different morphologies. The Water Electrolysis was coupled with photocatalytic decomposition of Water by irradiation of UV light on the modified anode. And a feasible process for the hydrogen production of Water Electrolysis assisted by photocatalysis (WEAP) was proposed and experimentally confirmed. The results show that the highly ordered, vertically oriented tubular arrays structure on Ni anode surface has better hydrogen production performance than random TiO2. In WEAP process, the maximum rate of hydrogen production is 2.77 ml/(h*cm2) when the anode modified by ordered TiO2 nanotube arrays, compared to traditional alkaline electrolytic cell for Water Electrolysis with Ni anode, H2-production rate increased by 139%.
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A feasible hydrogen evolution process of Water Electrolysis assisted by TiO2 nanotube photocatalysis
Journal of Industrial and Engineering Chemistry, 2013Co-Authors: Aiping Chen, Ming ChangAbstract:Abstract A feasible process called as the hydrogen evolution of Water Electrolysis assisted by photocatalysis (WEAP) was proposed and experimentally achieved. In comparison with traditional alkaline electrolytic cell for Water Electrolysis with Ni anode, H2-production rate increased by 118% and the applied direct voltage reduced by 14.5% in WEAP with photoactive Ni anode modified by TiO2 nanotubes.
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Enhanced hydrogen evolution process of Water Electrolysis assisted by photocatalysis
2011 International Conference on Materials for Renewable Energy & Environment, 2011Co-Authors: Hongbo He, Jindong Lu, Ming Chang, Aiping Chen, Chunzhong LiAbstract:TiO2 nanotubes were synthesized successfully by hydrothermal process using TiO2 powder and NaOH as the precursor. The anode of Water Electrolysis equipment was modified by prepared TiO2 nanotubes. Through photocatalytic hydrogen evolution coupled with Water Electrolysis, a new process of hydrogen evolution, called as the hydrogen evolution of Water Electrolysis assisted by photocatalysis(HEWEAP), was proposed and experimental achieved. The rate of hydrogen evolution of HEWEAP in the presence of TiO2 nanotubes increased by 23% comparing to Water Electrolysis. X-ray diffraction, UV-vis diffuse reflectance spectroscopy, FE-SEM, TEM and measurement of hydrogen evolution rate were used to characterize the catalyst.
Aiping Chen - One of the best experts on this subject based on the ideXlab platform.
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Fabrication of TiO2 film with different morphologies on Ni anode and application in photoassisted Water Electrolysis
Applied Surface Science, 2013Co-Authors: Aiping Chen, Haijun Dong, Ming ChangAbstract:Abstract The anode of an alkaline electrolytic cell for Water Electrolysis was modified by TiO2 photocatalysts with different morphologies. The Water Electrolysis was coupled with photocatalytic decomposition of Water by irradiation of UV light on the modified anode. And a feasible process for the hydrogen production of Water Electrolysis assisted by photocatalysis (WEAP) was proposed and experimentally confirmed. The results show that the highly ordered, vertically oriented tubular arrays structure on Ni anode surface has better hydrogen production performance than random TiO2. In WEAP process, the maximum rate of hydrogen production is 2.77 ml/(h*cm2) when the anode modified by ordered TiO2 nanotube arrays, compared to traditional alkaline electrolytic cell for Water Electrolysis with Ni anode, H2-production rate increased by 139%.
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A feasible hydrogen evolution process of Water Electrolysis assisted by TiO2 nanotube photocatalysis
Journal of Industrial and Engineering Chemistry, 2013Co-Authors: Aiping Chen, Ming ChangAbstract:Abstract A feasible process called as the hydrogen evolution of Water Electrolysis assisted by photocatalysis (WEAP) was proposed and experimentally achieved. In comparison with traditional alkaline electrolytic cell for Water Electrolysis with Ni anode, H2-production rate increased by 118% and the applied direct voltage reduced by 14.5% in WEAP with photoactive Ni anode modified by TiO2 nanotubes.
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Enhanced hydrogen evolution process of Water Electrolysis assisted by photocatalysis
2011 International Conference on Materials for Renewable Energy & Environment, 2011Co-Authors: Hongbo He, Jindong Lu, Ming Chang, Aiping Chen, Chunzhong LiAbstract:TiO2 nanotubes were synthesized successfully by hydrothermal process using TiO2 powder and NaOH as the precursor. The anode of Water Electrolysis equipment was modified by prepared TiO2 nanotubes. Through photocatalytic hydrogen evolution coupled with Water Electrolysis, a new process of hydrogen evolution, called as the hydrogen evolution of Water Electrolysis assisted by photocatalysis(HEWEAP), was proposed and experimental achieved. The rate of hydrogen evolution of HEWEAP in the presence of TiO2 nanotubes increased by 23% comparing to Water Electrolysis. X-ray diffraction, UV-vis diffuse reflectance spectroscopy, FE-SEM, TEM and measurement of hydrogen evolution rate were used to characterize the catalyst.
Kikuo Hattori - One of the best experts on this subject based on the ideXlab platform.
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prediction of production power for high pressure hydrogen by high pressure Water Electrolysis
Journal of Power Sources, 2004Co-Authors: Kazuo Onda, Takahiro Kyakuno, Kikuo HattoriAbstract:Recent attention focused on fuel cell electric vehicles (FCEVs) has created demand for the construction of hydrogen supply stations for FCEVs throughout the world. The hydrogen pressure supplied at the supply stations is intentionally high to increase the FCEVs driving mileage. Water Electrolysis can produce clean hydrogen by utilizing electricity from renewable energy without CO2 emission to the atmosphere when compared with the industrial fossil fuel reforming process. The power required for high-pressure Water Electrolysis, wherein Water is pumped up to a high-pressure, may be less than the power required for atmospheric Water Electrolysis, wherein the produced atmospheric hydrogen is pumped by a compressor, since the compression power for Water is much less than that for hydrogen-gas. In this study, the ideal Water Electrolysis voltage of up to 70 MPa and 250 ◦ C is estimated by referring to both the results of LeRoy et al. up to 10 MPa and 250 ◦ C, and the latest steam tables. Using this high-pressure Water Electrolysis voltage, the power required to produce high-pressure hydrogen by high-pressure Water Electrolysis is estimated to be about 5% less than that required for atmospheric Water Electrolysis, assuming compressor and pump efficiencies of 50%. © 2004 Elsevier B.V. All rights reserved.
Jun Chi - One of the best experts on this subject based on the ideXlab platform.
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Water Electrolysis based on renewable energy for hydrogen production
Chinese Journal of Catalysis, 2018Co-Authors: Jun ChiAbstract:Abstract As an energy storage medium, hydrogen has drawn the attention of research institutions and industry over the past decade, motivated in part by developments in renewable energy, which have led to unused surplus wind and photovoltaic power. Hydrogen production from Water Electrolysis is a good option to make full use of the surplus renewable energy. Among various technologies for producing hydrogen, Water Electrolysis using electricity from renewable power sources shows great promise. To investigate the prospects of Water Electrolysis for hydrogen production, this review compares different Water Electrolysis processes, i.e., alkaline Water Electrolysis, proton exchange membrane Water Electrolysis, solid oxide Water Electrolysis, and alkaline anion exchange membrane Water Electrolysis. The ion transfer mechanisms, operating characteristics, energy consumption, and industrial products of different Water Electrolysis apparatus are introduced in this review. Prospects for new Water Electrolysis technologies are discussed.
