Effect of Electrolyte Anions on the Activity of Iridium Oxide Catalysts for Water Electrolysis

• DOI: 10.1149/ma2023-02422085mtgabs
• Publication Date: 2024-02-08T19:57:35Z
• Authors: Weijie Cao; Tomoki Uchiyama; Neha Thakur; Mitsuharu Fujita; Ikkei Arima; Toshiki Watanabe; Kentaro Yamamoto; Tsuyoshi Takami; Toshiyuki Matsunaga; Yoshiyuki Kuroda; Shigenori Mitsushima; Yoshiharu Uchimoto
• Keywords: Electrolysis of water

Developing environmentally friendly and renewable energy sources is essential due to the environmental security issues caused by traditional combustion of fossil fuel-based sources. Therefore, as a clean sustainable carrier, hydrogen has attracted great attention in recent years. In this regard, water electrolysis utilizing produce considered one most promising technologies. It believed elucidation reaction mechanism highly active iridium oxides for further development cost-efficient PEM catalysts. The properties MEA could be affected many parameters such catalysts, operating temperature, pressure 1,2 . Another important factor cation impurities that can found circulating water, which severely degrade performance during operation electrolyze. However, there are less reports on anion SO 4 2- PO 3- study, relationship between electrolyte anions OER activity was investigated IrO x catalysts with different crystal structure. By using operando X-ray absorption spectroscopy (XAS), we electronic state Ir O under potential. degree crystallinity (SA3.5 SA58) were provided Tanaka Kikinzoku Kogyo K.K., Chemical & Refining Company named after their BET surface areas. These two samples then tested electrochemical concentrations phosphoric acid perchloric acid, respectively. measurements performed standard three-electrode cell connected an MPG-205-NUC system (Bio-Logic). cyclic voltammograms (CV) scanned from 0.1 V 1.2 vs. RHE at 50 mV s -1 activities subsequently linear sweep voltammetry (LSV) range 1.1 1.7 vs 10 −1 XAS collected home-made flow-type cell, where Pt wire worked counter reference electrodes, catalyst ink coated onto Nafion membrane prepare both window working electrode. circulated flow rate 100 mL min catalytic types content H 3 HClO Figure 1 shows CVs SA3.5 SA58 electrolyte. presence phosphate anions, showed tendency decrease redox 0.6 increasing concentration. On other hand, no obvious changes SA58. have effect specific adsorption low symmetry monoclinic phase (SA 3.5) more susceptible poisoning. 2 result examining poisoning soft XAS. K-edge results present formation µ -O (O-O) bond around 528.7 eV, previously observed Nong, H. N. et. al. through O-K edge process peak intensity eV amorphous same order activities. According potential dependence change pre-edge peak, hole Ir-O hybrid orbitals suppressed SA3.5. This indicates adsorbs site, inhibiting reaction. Acknowledgements work based obtained project (JPNP14021) commissioned New Energy Industrial Technology Development Organization (NEDO) Japan. References Zhang, Y.; Zhu, X.; G.; Shi, P.; Wang, A.-L.; et J. Mater. Chem. A: 2021 , 9, 5890-5914. Chen, Z.; Duan, Wei, W.; S.; Ni, B.-J.; Nano Energy: 2020 78, 105270. N.; Falling, L. J.; Bergmann, A.; Nature 587 (7834), 408-413.