Controlled Structural Activation of Iridium Single Atom Catalyst for High-Performance Proton Exchange Membrane Water Electrolysis

Wonjae Ko; Jaehyuk Shim; Hyunsoo Ahn; Hee Jung Kwon; Kangjae Lee; Yoon Jung; Wytse Hooch Antink; Chan Woo Lee; Sungeun Heo; Seongbeom Lee; Junghwan Jang; Jiheon Kim; Hyeon Seok Lee; Sung-Pyo Cho; Byoung-Hoon Lee; Minho Kim; Yung-Eun Sung; Taeghwan Hyeon

doi:10.1021/jacs.4c11442

Controlled Structural Activation of Iridium Single Atom Catalyst for High-Performance Proton Exchange Membrane Water Electrolysis

J Am Chem Soc. 2025 Jan 22;147(3):2369-2379. doi: 10.1021/jacs.4c11442. Epub 2025 Jan 8.

Authors

Wonjae Ko^{1

2}, Jaehyuk Shim^{1

2}, Hyunsoo Ahn^{1

2}, Hee Jung Kwon³, Kangjae Lee^{1

2}, Yoon Jung^{1

2}, Wytse Hooch Antink^{1

2}, Chan Woo Lee^{1

2}, Sungeun Heo^{1

2}, Seongbeom Lee^{1

2}, Junghwan Jang^{1

2}, Jiheon Kim^{1

2}, Hyeon Seok Lee^{1

2}, Sung-Pyo Cho⁴, Byoung-Hoon Lee^{1

2

5}, Minho Kim³, Yung-Eun Sung^{1

2}, Taeghwan Hyeon^{1

2}

Affiliations

¹ Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.
² School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea.
³ Department of Applied Chemistry, Kyung Hee University, Yongin 17104, Republic of Korea.
⁴ National Center for Inter-University Research Facilities, Seoul National University, Seoul 08826, Republic of Korea.
⁵ KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea.

PMID: 39778120
DOI: 10.1021/jacs.4c11442

Abstract

Iridium single atom catalysts are promising oxygen evolution reaction (OER) electrocatalysts for proton exchange membrane water electrolysis (PEMWE), as they can reduce the reliance on costly Ir in the OER catalysts. However, their practical application is hindered by their limited stability during PEMWE operation. Herein, we report on the activation of Ir-doped CoMn₂O₄ in acidic electrolyte that leads to enhanced activity and stability in acidic OER for long-term PEMWE operation. In-depth material characterization combined with electrochemical analysis and theoretical calculations reveal that activating Ir-doped CoMn₂O₄ induces controlled restructuring of Ir single atoms to IrO_x nanoclusters, resulting in an optimized Ir configuration with outstanding mass activity of 3562 A g_Ir^-1 at 1.53 V (vs RHE) and enhanced OER stability. The PEMWE using activated Ir-doped CoMn₂O₄ exhibited a stable operation for >1000 h at 250 mA cm^-2 with a low degradation rate of 0.013 mV h^-1, demonstrating its practical applicability. Furthermore, it remained stable for more than 400 h at a high current density of 1000 mA cm^-2, demonstrating long-term durability under practical operation conditions.