Fundamental and Applied Study on Hydrogen Gas Production Utilizing Metal-Chalcogen Melts as an Electrode

Research Project

Project/Area Number	63550495
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	金属精錬・金属化学
Research Institution	Osaka University
Principal Investigator	YAO Shinya Osaka Univ. Dept.of Engr. Asst.Prof., 工学部, 助教授 (90029299)
Project Period (FY)	1988 – 1989
Project Status	Completed (Fiscal Year 1989)
Budget Amount *help	¥2,800,000 (Direct Cost: ¥2,800,000) Fiscal Year 1989: ¥1,300,000 (Direct Cost: ¥1,300,000) Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Hydrogen Gas Production / Metal-Chalcogen Melts / Tin-Tellurium Melts / Oxygen Concentration Cell / Potentiostatic Experiments / 金属ーカルコゲン融体 / スズーテルル融体 / 酸素の活量係数 / 水素製造 / 固体電解質
Research Abstract	Study on the hydrogen production was performed utilizing Sn-40at.%Te Melt in which the saturation solubility is relatively large. An electrochemical cell:Air, Pt/ZrO_2(+CaO)/O in Sn-40at.%Te melt was constructed. Argon gas was passed through water(0 ﾟC), and the production experiment was started at 1123 K by applying a voltage(V) to the cell(I). After confirming a steady electric current(I), the temperature of the water was changed to another one(30, 50 or 70 ﾟC), and the dependence of the current on the water temperature was investigated. For an electrode with high production efficiency, the dependence should be larger; similar experiments with porous platinum or pure Sn melt instead of the Sn-Te melt were also performed and compared. For pure Sn Melt, the dependence of the current on the water temperature is largest, and the efficiencies with the Sn-Te melt and platinum were comparable. This results indicate that the saturation solubility of oxygen is not the most important factor. Although differing from expectation, the rate of oxidation and the following deoxidation is most important. For the Sn melt electrode, SnO_2 formed on the above surface of the melt may move promptly toward the interface of the melt-zirconia interface due to the difference of interfacial tension. The present result, that is, the property of Sn melt is far excellent than that of porous Pt which is used for conventional hydrogen production. Mixing the melts such as Sn with oxide powder electrode, which seems one of the attractive candidates may lead to the electrode having far high efficiency.