Defect‐Rich Nitrogen Doped Co3O4/C Porous Nanocubes Enable High‐Efficiency Bifunctional Oxygen Electrocatalysis

By Zhichao Wang, Wenjia Xu, Xiaokang Chen, Yanhua Peng, Yanyan Song, Chunxiao Lv, Hongli Liu, Junwei Sun, Ding Yuan, Xiyan Li and 3 more. Advanced Functional Materials, 2019

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Heteroatom doping plays a significant role in optimizing the catalytic performance of electrocatalysts. However, research on heteroatom doped electrocatalysts with abundant defects and well‐defined morphology remain a great challenge. Herein, a class of defect‐engineered nitrogen‐doped Co3O4 nanoparticles/nitrogen‐doped carbon framework (N‐Co3O4@NC) strongly coupled porous nanocubes, made using a zeolitic imidazolate framework‐67 via a controllable N‐doping strategy, is demonstrated for achieving remarkable oxygen evolution reaction (OER) catalysis. X‐ray photoelectron spectroscopy, X‐ray absorption fine structure, and electron spin resonance results clearly reveal the formation of a considerable amount of nitrogen dopants and oxygen vacancies in N‐Co3O4@NC. The defect engineering of N‐Co3O4@NC makes it exhibit an overpotential of only 266 mV to reach 10 mA cm−2, a low Tafel slope of 54.9 mV dec−1 and superior catalytic stability for OER, which is comparable to that of commercial RuO2. Density functional theory calculations indicate N‐doping could promote catalytic activity via improving electronic conductivity, accelerating reaction kinetics, and optimizing the adsorption energy for intermediates of OER. Interestingly, N‐Co3O4@NC also shows a superior oxygen reduction reaction activity, making it a bifunctional electrocatalyst for zinc–air batteries. The zinc–air battery with the N‐Co3O4@NC cathode demonstrates superior efficiency and durability, showing the feasibility of N‐Co3O4/NC in electrochemical energy devices.

Subfields: Electrical and Electronic Engineering, Renewable Energy, Sustainability and the Environment

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