Electrolytic hydrogen production assuming natural energy using natural water such as seawater as electrolyte resource.

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K12239
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64030:Environmental materials and recycle technology-related
• Research Institution: Yamaguchi University
• Principal Investigator: Endo Nobutaka 山口大学, 大学院創成科学研究科, 講師 (40314819)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 電解水素製造 / 海水電解 / 選択性制御 / 酸素 / 塩素

Outline of Final Research Achievements

A flow-type electrolytic cell with a thin plate type flow path was prepared and electrolyzed a 3.5wt% NaCl solution as simulated seawater. In electrolysis performed at a supply rate of 50 ml/min, the chlorine concentration at the outlet was 40 to 50% of the theoretical value, and the remaining electricity was shown to be consumed for oxygen production from changes in the pH of the outlet solution. This was thought to be due to the flow of the solution near the electrodes being different from that of the flow path (bulk solution in the electrolytic cell), and the difference in the rate of supply of reactant ions there. The effects of applied current and solution supply rate, and the arrangement of cell elements, supported this. These results show that by changing the cell structure and operating conditions, it is possible to change the chlorine/oxygen selectivity, that is, the production ratio, even in seawater electrolysis.

Free Research Field

電気化学

Academic Significance and Societal Importance of the Research Achievements

今後の水素需要の増大には、それ単独で採算が取れるクリーンエネルギーによる水電解法の開発が不可欠である。海水および食塩の電解液資源利用は、入手容易性からコスト低減に大きく貢献する。しかし塩素は滅菌などに利用できるが、その腐食性・毒性から過剰な生産は望ましくない。本研究によって塩素生成量を自在に制御できれば、滅菌剤として用いる塩素を現地で製造できる。これにより、安価な電解液資源の利用、自然水利用に必要な滅菌剤の内部調達、腐食性や毒性のある副生物の過剰生産による処理費用の低減ができる。これは自然エネルギーの面積効率から、中規模になると予想される水素製造プラントでは、その貢献は大きいと考えられる。