Construction of Surface Ruoct─O─Cooct Units With Optimized Cooct Spin States for Enhanced Oxygen Reduction and Evolution

The introduction of noble metal into spinel structure is an effective strategy to develop efficient oxygen evolution/reduction reaction (OER/ORR) catalysts. Herein, surface Cooct is substituted by Ruoct in Rux‐Mn0.5Co2.5‐xO4/NCNTs by ion‐exchange, where presence of Ruoct─O─Cooct unit facilitates ele...

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Veröffentlicht in:Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-11, Vol.20 (47), p.e2405865-n/a
Hauptverfasser: Yu, Can‐Wen, Chen, Zi‐Qiang, Xu, Hong‐Yi, Ouyang, Ting, Liu, Zhao‐Qing
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Sprache:eng
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Zusammenfassung:The introduction of noble metal into spinel structure is an effective strategy to develop efficient oxygen evolution/reduction reaction (OER/ORR) catalysts. Herein, surface Cooct is substituted by Ruoct in Rux‐Mn0.5Co2.5‐xO4/NCNTs by ion‐exchange, where presence of Ruoct─O─Cooct unit facilitates electron transfer. This strong electron coupling effect leads downward shift in d‐band center and a narrowing of d‐p bandgap. The increased charge density of Cooct bridged with Ruoct dioxygen optimizes adsorption of oxygen intermediates (*OH) and occupation of electrons in eg‐orbital octahedral. The measured ORR/OER voltage difference is only 0.71 V. The peak power density of assembled zinc–air battery reaches 148.8 mW h cm−2, and energy density at 100 mA cm−2 reaches 813.6 mA h gZn−1, approaching a theoretical value of 820 mA h gZn−1. The catalyst demonstrates stable operation for over 500 h at 10 mA cm−2 and over 200 h at 50 mA cm−2. This work provides new insights to guide fabrication of advanced oxygen electrocatalysts. The substitution of surface Cooct by Ruoct in Rux‐Mn0.5Co2.5‐xO4/NCNTs, where the presence of strong electron coupling effect due to Ruoct–O–Cooct unit enables charge redistribution, allowing Cooct with optimal eg‐orbital electron number (eg = 1) in coordination with Ruoct dioxygen, thereby enhancing OER/ORR catalytic activity (∆E = 0.71 V).
ISSN:1613-6810
1613-6829
1613-6829
DOI:10.1002/smll.202405865