Iridium-Iron Diatomic Active Sites for Efficient Bifunctional Oxygen Electrocatalysis

• Type: Article in International Scientific Journal
• Date: 2022

Authors

Yu, ZP (Author) Other; Si, CW (Author) Other; LaGrow, AP (Author) Other; Tai, ZX (Author) Other; Caliebe, WA (Author) Other; Tayal, A (Author) Other; Sampaio, M.J. (Author) FEUP; Sousa, JPS (Author) Other; Amorim, I (Author) Other; Araujo, A (Author) Other; Meng, LJ (Author) Other; Joaquim Luís Faria (Author) FEUP; Xu, JY (Author) Other; Li, B (Author) Other; Liu, LF (Author) Other

Journal

Title: Acs Catalysis

Vol. 12

Pages: 9397-9409

ISSN: 2155-5435

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 9397 Citations

Other information

Authenticus ID: P-00X-2KS

DOI: 10.1021/acscatal.2c01861

Abstract (EN): Diatomic catalysts, particularly those with heteronuclear active sites, have recently attracted considerable attention for their advantages over single-atom catalysts in reactions involving multielectron transfers. Herein, we report bimetallic iridium-iron diatomic catalysts (IrFe-N-C) derived from metal-organic frameworks in a facile wet chemical synthesis followed by postpyrolysis. We use various advanced characterization techniques to comprehensively confirm the atomic dispersion of Ir and Fe on the nitrogen-doped carbon support and the presence of atomic pairs. The as-obtained IrFe-N-C shows substantially higher electrocatalytic performance for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) when compared to the single-atom counterparts (i.e., Ir-N-C and Fe-N-C), revealing favorable bifunctionality. Consequently, IrFe-N-C is used as an air cathode in zinc-air batteries, which display much better performance than the batteries containing commercial Pt/C + RuO2 benchmark catalysts. Our synchrotron-based X-ray absorption spectroscopy experiments and density functional theory (DFT) calculations suggest that the IrFe dual atoms presumably exist in an IrFeN6 configuration where both Ir and Fe coordinates with four N atoms and two N atoms are shared by the IrN4 and FeN4 moieties. Furthermore, the Fe site contributes mainly to the ORR, while the Ir site plays a more important role in the OER The dual-atom sites work synergistically, reducing the energy barrier of the rate-determining step and eventually boosting the reversible oxygen electrocatalysis. The IrFe-N-C catalysts hold great potential for use in various electrochemical energy storage and conversion devices.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13