Metal–Organic-Framework-Derived Co–Fe Bimetallic Oxygen Reduction Electrocatalysts for Alkaline Fuel Cells

• Published in: Journal of the American Chemical Society 2019-07, Vol.141 (27), p.10744-10750
• Main Authors: Xiong, Yin, Yang, Yao, DiSalvo, Francis J, Abruña, Héctor D
• Format: Article
• Language: English
• Subjects: Chemistry
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.9b03561

The oxygen reduction reaction (ORR) is considered the cornerstone for regenerative energy conversion devices involving fuel cells and electrolyzers. The development of non-precious-metal electrocatalysts is of paramount importance for their large-scale commercialization. Here, Co–Fe binary alloy embedded bimetallic organic frameworks (BMOF)­s based on carbon nanocomposites have been designed with a compositionally optimized template, by a facile host–guest strategy, for ORR in alkaline media. The electrocatalyst exhibits promising electrocatalytic activity for ORR with a half-wave potential of 0.89 V in 0.1 M NaOH, comparable to state-of-the-art Pt/C electrocatalysts. More importantly, it exhibits robust durability after 30 000 potential cycles. Scanning transmission electron microscopy (STEM) and quantitative energy-dispersive X-ray (EDX) spectroscopy suggest that the Co–Fe alloy nanoparticles have a homogeneous elemental distribution of Co and Fe at the atomic-scale optimized BMOF and Co/Fe ratio of 9:1. The long-term durability is attributed to its ability to maintain its structural and compositional integrity after the cycling process, as evidenced by STEM-EDX analysis. This work provides valuable insights into the design and fabrication of novel platinum-group-metals-free highly active ORR electrocatalysts in alkaline media.