(385a) Harmonic Enhancement of Activity and Stability of Iridium-Based Catalysts for Proton Exchange Membrane Water Electrolysis

Recently, the proton exchange membrane water electrolysis (PEMWE) which can store the surplus electricity as a form of transportable hydrogen has been attracting great attention for expanding the large-scale renewable electricity using sun and wind for the carbon-neutral society [1]. Due to the slow oxygen evolution reaction (OER) that can generate the oxygen in the PEMWE and harsh reaction conditions like low pH and high voltage in the anode during the electrolysis, the precious metal oxide catalysts such as IrO₂ and RuO₂ should be adapted in the membrane electrode assembly (MEA). However, there is a challenge to decrease the amount of the noble metal to the level of 0.01 g/kW [2] in the MEA to commercialize PEMWE at a GW per year scale in near future. Thus, the catalysts for the OER, which are mainly iridium(Ir)-based composition, have been developing for harmonic improving the activity and stability through many measures such as mixed metal oxides [3], core-shell nanostructure [4], and supported catalysts [5].

In this presentation, new synthetic approaches for harmonic enhancement of the activity and stability will be discussed. For example, a novel solution process using ethylene glycol, formic acid, and sodium acetate for breaking the trade-off relationship of the activity and stability [6] is presented, which is very suitable for mass production of IrOx catalyst because it is simple and less time-consuming. As the second example, the modified Adams fusion synthesis using glycol as an additive, which can produce a higher surface area of IrOx catalyst is displayed. The harmonized activity and stability obtained by a modified Adams method results in the enhancement of the MEA performance under PEMWE conditions.

[1] IRENA “Innovation Landscape Brief: Renewable Power-to-Hydrogen”, International Renewable Energy Agency, Abu Dhabi, 2019 at www.irena.org/publications.

[2] M. Bernt, A. Siebel, H. A. Gasteiger, J. Electrochem. Soc., 165 (2018) F305.

[3] S.W. Lee, C. Baik, T.-Y. Kim, C. Pak, Catal. Today, 352 (2020) 39.

[4] C. Van Pham, M. Bühler, J. Knöppel, M. Bierling, D. Seeberger, D. Escalera-López, K.J. Mayrhofer, S. Cherevko, S. Thiele, Appl. Catal. B., 269 (2020) 118762.

[5] S. Zhao, A. Stocks, B. Rasimick, K. More, H. Xu, J. Electrochem. Soc., 165 (2018) F82.

[6] S. W. Lee, C. Baik, D.-H. Kim, C. Pak, J. Power Sources, 493 (2021) 229689.