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High-valence metal doping on cobalt-iron (oxy) hydroxide to activate the lattice oxygen for boosting oxygen evolution performance
The precise modulation of the electronic structure of cobalt-iron (oxy) hydroxides to facilitate the lattice oxygen mechanism (LOM) activation is essential for lowering the energy barriers of the alkaline oxygen evolution reaction (OER), and promoting the energy-saving water electrolysis technology....
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Published in: | Journal of alloys and compounds 2024-12, Vol.1008, p.176678, Article 176678 |
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Main Authors: | , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites |
Online Access: | Get full text |
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Summary: | The precise modulation of the electronic structure of cobalt-iron (oxy) hydroxides to facilitate the lattice oxygen mechanism (LOM) activation is essential for lowering the energy barriers of the alkaline oxygen evolution reaction (OER), and promoting the energy-saving water electrolysis technology. In this study, we propose the introduction of high-valence heterometal (Mo, V, W) to regulate the orbital hybridization state of the asymmetric Co-O-Fe coupling configuration. Through systematic characterization and theoretical calculations, we demonstrate that the high-valence metal sites act as electron acceptors, which tailor the 2p orbitals state of the adjacent lattice oxygen, enhancing the covalency of the metal-oxygen bond to help activate the lattice oxygen sites. Undergoing the LOM pathway, the optimized candidate of Mo-CoFeOxHy exhibits the best OER performance, with an overpotential of 240/340 mV at 10/400 mA cm−2, which is significantly lower than that of pristine CoFeOxHy and commercial RuO2. Encouragingly, a self-constructed alkaline flow-type water electrolyze with the catalyst pair of Pt/C and Mo-CoFeOxHy shows promising performance of 2.03 V at 100 mA cm−2, and also possesses long-term durability, with almost no activity decay after 100 hours of operation. We validate that this universal modification strategy can provide general guidance for rational design of OER catalysts.
•The Mo-CoFeOOH catalyst was prepared by one-step electrodeposition. The catalyst has higher active area and longer stability.•Through theoretical calculation, we show that the 2p orbitals of lattice oxygen can be adjusted by high metal doping.•In continuous anion exchange membrane cells, the catalyst has reached industrial grade operating standards. |
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ISSN: | 0925-8388 |
DOI: | 10.1016/j.jallcom.2024.176678 |