Metal-organic framework-derived core-shell-structured nitrogen-doped CoCx/FeCo@C hybrid supported by reduced graphene oxide sheets as high performance bifunctional electrocatalysts for ORR and OER

• Published in: Journal of catalysis Vol. 371; pp. 185 - 195
• Main Authors: Fang, Hengyi, Huang, Taizhong, Sun, Yue, Kang, Baotao, Liang, Dong, Yao, Shuo, Yu, Jiemei, Dinesh, M. Mayilvel, Wu, Si, Lee, Jin Yong, Mao, Shun
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-03-2019
• Subjects: Bifunctional; Electrocatalysts; Metal-organic framework; Nitrogen-doped core-shell; Oxygen evolution reaction; Oxygen reduction reaction; Bifunctional; Metal-organic framework; Oxygen evolution reaction; Nitrogen-doped core-shell; Electrocatalysts; Oxygen reduction reaction
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2019.02.005

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•MOFs-deriver N-doped CoCx/FeCo@C/rGO was synthesized as a catalyst for ORR.•The ORR activity of N-doped CoCx/FeCo@C/rGO was higher than that of the Pt/C.•The OER activity of N-doped CoCx/FeCo@C/rGO was higher than that of the RuO2.•The synergistic effect of CoCx/FeCo and N-doped carbon results in the activity.
Metal-organic framework derived materials have a great promise as non-precious metal-based electrocatalysts for large-scale applications of energy storage and transition devices with low-cost and high efficiency. Here, we report a high performance core-shell-structured nitrogen-doped CoCx/FeCo@C/reduced graphene oxide (rGO) hybrid, which is derived from Fe-doped Co3[Co(CN)6]2 MOFs, as bifunctional catalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Structure characterizations show that the carbon shell of CoCx/FeCo and graphene support are bonded to each other, which offer a large surface area and stable anchoring sites for the CoCx/FeCo. Electrochemical tests show that N-doped CoCx/FeCo@C/rGO hybrid exhibits superior onset potential (1.0183 V vs RHE), half-wave potential (0.9653 V vs RHE), peak current intensity (0.9233 mA/cm−2) and long-term durability for ORR than those of Pt/C (onset potential, half-wave potential and peak current intensity are 1.0174 V and 0.9213 V, 0.8233 mA/cm−2, respectively) in 0.1 M KOH electrolyte. The overpotential of the hybrid for OER is only ∼390 mV at a current intensity of 10 mA/cm−2, which is close to that of the RuO2. The excellent electrocatalytic properties of this hybrid make it a great potential to be substitute for precious-based catalysts for ORR and OER in fuel cells and water splitting.