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A solid oxide electrolyzer cell (SOEC) is a solid oxide fuel cell that runs in regenerative mode to achieve the electrolysis of water and which uses a solid oxide, or ceramic, electrolyte to produce oxygen and hydrogen gas.〔(Durability of solid oxide electrolysis cells for hydrogen production )〕 The production of pure hydrogen is compelling because it is a clean fuel that can be stored easily, thus making it a potential alternative to batteries, which have a low storage capacity and create high amounts of waste materials.〔Ni M, Leung MKH, Leung DYC, Sumathy K. A review and recent developments in photocatalytic water-splitting using TiO2 for hydrogen production. Renewable Sustainable Energy Rev 2007;11(3):401–25.〕 Electrolysis is currently the most promising method of hydrogen production from water due to high efficiency of conversion and relatively low required energy input when compared to thermochemical and photocatalytic methods.〔Ni, M., Leung, M. K. H., & Leung, D. Y. C. (2008). Technological development of hydrogen production by solid oxide electrolyzer cell (SOEC). International Journal of Hydrogen Energy, 33, 2337–2354. doi:10.1016/j.ijhydene.2008.02.048〕 ==Principle== Solid oxide electrolyzer cells operate at temperatures which allow high-temperature electrolysis〔(A reversible planar solid oxide fuel-assisted electrolysis cell )〕 to occur, typically between 500 and 850 °C. These operating temperatures are similar to those conditions for an SOFC. The net cell reaction yields hydrogen and oxygen gases. The reactions for one mole of water are shown below, with oxidation of water occurring at the anode and reduction of water occurring at the cathode. Anode: H2O ---> 1/2O2 + 2H+ + 2e− Cathode: 2H2O + 2e− ---> H2 + 2OH− Net Reaction: H2O ---> H2 + 1/2O2〔(Electrolysis of water using an electrical current )〕 Electrolysis of water at 298 K (25 °C) requires 285.83 kJ of energy in order to occur,〔(Electrolysis of Water )〕 and the reaction is increasingly endothermic with increasing temperature. However, the energy demand may be reduced due to the Joule heating of an electrolysis cell, which may be utilized in the water splitting process at high temperatures. Research is ongoing to add heat from external heat sources such as concentrating solar thermal collectors and geothermal sources.〔(Can high temperature steam electrolysis function with geothermal heat? )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Solid oxide electrolyser cell」の詳細全文を読む スポンサード リンク
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