In situ synthesis of Co 3 O 4 nanoparticles confined in 3D nitrogen-doped porous carbon as an efficient bifunctional oxy
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In situ synthesis of Co3O4 nanoparticles confined in 3D nitrogendoped porous carbon as an efficient bifunctional oxygen electrocatalyst Zhi-Yuan Wang* , Shun-Da Jiang, Chan-Qin Duan, Dan Wang, Shao-Hua Luo, Yan-Guo Liu*
Received: 14 June 2020 / Revised: 25 August 2020 / Accepted: 28 August 2020 / Published online: 14 September 2020 Ó GRINM Bohan (Beijing) Publishing Co., Ltd 2020
Abstract The rational exploitation of non-precious metal catalyst with high activity, strong durability and low cost for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of vital importance for metal– air batteries. Herein, a composite of Co3O4 nanoparticles confined in three-dimensional (3D) N-doped porous carbon (Co-NpCs) was prepared by a simple freeze-drying and in situ pyrolysis method. The effect of different dosages of Co(NO3)2 on the catalytic performance was discussed. The Co-NpC-12% exhibits the best catalytic performance (E1/2 = 0.78 V, better stability than 20% Pt/C) in ORR and in OER among all the as-synthesized samples. Furthermore, it also exhibits the best bifunctional activity (DE = 0.849 V). The excellent properties of Co-NpCs are mainly due to the synergy between Co3O4 and carbon. Firstly, a high Co3O4 loading amount can boost the defect level of the N-doped hierarchical porous carbon and expose more active sites. Secondly, the unique in situ pyrolysis guarantees a largearea contact between Co3O4 and carbon as well as a strong C–O–Co bonding, which promotes charge transfer, avoids the peeling of Co3O4 nanoparticles and effectively Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12598-020-01581-4) contains supplementary material, which is available to authorized users. Z.-Y. Wang*, S.-D. Jiang, C.-Q. Duan, D. Wang, S.-H. Luo, Y.-G. Liu* School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China e-mail: [email protected] Y.-G. Liu e-mail: [email protected] Z.-Y. Wang, Y.-G. Liu Key Laboratory of Dielectric and Electrolyte Functional Material-Hebei Province, Qinhuangdao 066004, China
improves the stability of the material. This work is expected to offer a feasible strategy to produce metal oxide/carbon nanocomposite and push forward the development of bifunctional electrocatalyst with high activity and stability. Keywords Bifunctional electrocatalyst; Co3O4; Nitrogendoped porous carbon; In situ synthesis
1 Introduction Nowadays, the heavy use and dependence on fossil fuels have led to serious environmental pollution and energy shortage; therefore, the exploitation of clean, efficient and sustainable green energy is of great significance [1–3]. Metal–air batteries are widely considered to be promising renewable energy conversion technology because of their high theoretical energy densities [4, 5]. Unfortunately, as the critical step of the above technology, oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are commonly sluggish and have large overpotential, which li
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