2023 Fiscal Year Final Research Report
Development of electrodeposition technique of iridium oxide having both high activity and durability for oxygen evolution reaction
| Project/Area Number |
20K05157
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 一般 |
|---|
| Review Section |
Basic Section 26050:Material processing and microstructure control-related
|
|---|
| Research Institution | Shibaura Institute of Technology |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2020-04-01 – 2024-03-31
|
| Keywords | 水和型酸化イリジウム / 電析法 / 電析速度 / OER活性 / OER耐性 |
|---|
| Outline of Final Research Achievements |
By exploring the dependence of the bath composition for iridium oxide electrodeposition proposed by Yamanaka in 1989 on the deposition properties, activity and durability of OER, and bath stability, new electrodeposition bath which is able to form hydrous iridium oxide (IrOx) with comparable activity and durability of OER at the eight times faster rate compared with Yamanaka bath. The coulombic efficiency of electrodeposition depends on the potential applied to Ti substrates: 0% (~ 0.47 V vs. Ag|AgCl) due to the side reaction, increases with potential, sharply decreases above 0.65 V due to OER at deposited IrOx. We propose the potentiostatic deposition at 0.60 V as the method with minimal influences of side reactions.
IrOx formed from the present bath reveals greater OER activity than anhydrous IrO2 by the conventional thermal decomposition. The OER current is enhanced on porous IrOx electrodes obtained by depositing IrOx on porous titanium substrates under electrolyte flow conditions.
|
| Free Research Field |
電気化学
|
| Academic Significance and Societal Importance of the Research Achievements |
山中液は高い安定性を持つために多くの既往研究で利用されているが、電析反応、電析液成分の役割などは未解明である。本研究から、シュウ酸がIr4+の配位子でない可能性が高いこと、機序は不明であるがシュウ酸は液安定化に寄与すること、電析活性種は[Ir(OH)6]－2であることなどがわかった。
電析膜のOER耐性を既往研究より厳しい電解陽極利用に近い条件で検討し、電析法による水和型IrOxが高いOER活性のみならず耐性も要求される用途に展開できる可能性を示した。
|
