Electronic Coupling of Cobalt Nanoparticles to Nitrogen-Doped Graphene for Oxygen Reduction and Evolution Reactions
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- 作者：Dr. Chaohe Xu ; Dr. Meihua Lu ; Binggong Yan ; Dr. Yi Zhan ; Dr. Palani Balaya ; Prof. Li Lu and Prof. Jim Yang Lee
- 刊名：ChemSusChem
- 出版年：2016
- 出版时间：November 9, 2016
- 年：2016
- 卷：9
- 期：21
- 页码：3067-3073
- 全文大小：1942K
- ISSN：1864-564X
文摘
The rational design of nonprecious-metal electrocatalysts with activities comparable to or greater than that of platinum is extremely valuable to the development of high energy density metal–air batteries. Herein, the two-step preparation of a highly active oxygen electrocatalyst based on ultrasmall cobalt nanoparticles stabilized in a nitrogen-doped graphene matrix is reported. The catalyst performs as well as the commercial Pt/C catalyst in the oxygen reduction reaction, and better than the Pt/C catalyst in the oxygen evolution reaction. This particular electrocatalyst could significantly lower the overpotentials of oxygen electrochemical reactions in aqueous lithium–air batteries to attain a round-trip efficiency of about 79.0 % at a current density of 0.1 mA cm−2, thereby surpassing the performance of the commercial Pt/C catalyst. The good performance may be attributed to strong metal–support interactions, maximized by a high dispersion of ultrasmall cobalt nanocrystals in a nitrogen-doped graphene matrix, which yields electrocatalytic properties greater than the sum of its parts.