Defects‐Induced In‐Plane Heterophase in Cobalt Oxide Nanosheets for Oxygen Evolution Reaction

Journal Article · 14 November 2019 · Small

DOI: https://doi.org/10.1002/smll.201904903 · OSTI ID:1579423

Liu, Zhijuan ^[1]; Xiao, Zhaohui ^[2]; Luo, Gan ^[3]; Chen, Ru ^[2]; Dong, Chung‐Li ^[4]; Chen, Xiaobo ^[5]; Cen, Jiajie ^[5]; Yang, Haotian ^[5]; Wang, Yanyong ^[2]; Su, Dong ^[5]; Li, Yafei ^[3]; Wang, Shuangyin  ^[2]

---

1. State Key Laboratory of Chem/Bio‐sensing and Chemometrics College of Chemistry and Chemical Engineering Hunan University Changsha 410082 P. R. China, Center for Functional Nanomaterials Brookhaven National Laboratory Upton NY 11973 USA
2. State Key Laboratory of Chem/Bio‐sensing and Chemometrics College of Chemistry and Chemical Engineering Hunan University Changsha 410082 P. R. China
3. College of Chemistry and Materials Science Nanjing Normal University Nanjing 210046 P. R. China
4. Department of Physics Tamkang University Tamsui 251 Taiwan
5. Center for Functional Nanomaterials Brookhaven National Laboratory Upton NY 11973 USA

Abstract Cobalt oxides as efficient oxygen evolution reaction (OER) electrocatalysts have received much attention because of their rich reserves and cheap cost. There are two common cobalt oxides, Co ₃ O ₄ (spinel phase, stable but poor intrinsic activity) and CoO (rocksalt phase, active but easily be oxidatized). Constructing Co ₃ O ₄ /CoO heterophase can inherit both characteristic features of each component and form a heterophase interface facilitating charge transfer, which is believed to be an effective strategy in designing excellent electrocatalysts. Herein, an atomic arrangement engineering strategy is applied to improve electrocatalytic activity of Co ₃ O ₄ for the OER. With the presence of oxygen vacancies, cobalt atoms at tetrahedral sites in Co ₃ O ₄ can more easily diffuse into interstitial octahedral sites to form CoO phase structure as revealed by periodic density functional theory computations. The Co ₃ O ₄ /CoO spinel/rocksalt heterophase can be in situ fabricated at the atomic scale in plane. The overpotential to reach 10 mA cm ⁻² of Co ₃ O ₄ /CoO is 1.532 V, which is 92 mV smaller than that of Co ₃ O ₄ . Theoretical calculations confirm that the excellent electrochemical activity is corresponding to a decline in average p ‐state energy of adsorbed‐O on the Co ₃ O ₄ /CoO heterophase interface. The reaction Gibbs energy barrier has been significantly decreased with the construction of the heterophase interface.

• Sponsoring Organization: USDOE
• Grant/Contract Number: NONE; SC0012704
• OSTI ID: 1579423
• Journal Information: Small, Journal Name: Small Journal Issue: 50 Vol. 15; ISSN 1613-6810
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Germany
• Language: English