Selective Etching of Metal-Organic Frameworks for Open Porous Structures: Mass-Efficient Catalysts with Enhanced Oxygen Reduction Reaction for Fuel Cells

Jingjing Li; Wei Xia; Xingtao Xu; Dong Jiang; Ze-Xing Cai; Jing Tang; Yanna Guo; Xianli Huang; Tao Wang; Jianping He; Buxing Han; Yusuke Yamauchi

doi:10.1021/jacs.3c05544

Selective Etching of Metal-Organic Frameworks for Open Porous Structures: Mass-Efficient Catalysts with Enhanced Oxygen Reduction Reaction for Fuel Cells

J Am Chem Soc. 2023 Dec 20;145(50):27262-27272. doi: 10.1021/jacs.3c05544. Epub 2023 Dec 10.

Authors

Jingjing Li^{1

2}, Wei Xia³, Xingtao Xu⁴, Dong Jiang⁴, Ze-Xing Cai⁵, Jing Tang³, Yanna Guo², Xianli Huang¹, Tao Wang¹, Jianping He¹, Buxing Han^{3

6}, Yusuke Yamauchi^{4

7

8}

Affiliations

¹ College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
² Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo, 169-8555, Japan.
³ School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, Shanghai 200062, China.
⁴ Department of Materials Process Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan.
⁵ School of Environmental Science and Engineering, Kochi University of Technology, 185 Miyanokuchi, Tosayamada Kami City, Kochi, 782-8502, Japan.
⁶ Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid and Interface and Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
⁷ Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia.
⁸ Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea.

PMID: 38071659
DOI: 10.1021/jacs.3c05544

Abstract

Fe-N_x-C-based single-atom (SA-Fe-N-C) catalysts have shown favorable oxygen reduction reaction (ORR) activity. However, their application in proton exchange membrane fuel cells is hindered by reduced performance owing to the thick catalyst layer, restricting mass transfer and the O₂ supply. Metal-organic frameworks (MOFs) are a promising class of crystal materials, but their narrow pores exacerbate the sluggish mass-transport properties within the catalyst layer. This study developed an approach for constructing an open-pore structure in MOFs via chelation-assisted selective etching, resulting in atomically dispersed Fe atoms anchored on an N, S co-doped carbon framework. The open-pore structure reduces oxygen transport resistance in the membrane electrode assembly (MEA) with unprecedented ORR activity and stability, as evidenced by finite element simulations. In an acidic electrolyte, the OP-Fe-NC catalyst shows a half-wave potential of 0.89 V vs RHE, surpassing Pt/C by 20 mV, and a current density of 29 mA cm^-2 at 0.9 V_iR-free in the MEA. This study provides an effective structural strategy for fabricating electrocatalysts with high mass efficiency and atomic precision for energy storage and conversion devices.