Enhanced Electrocatalytic Activity of Murdochite-Type Ni6MnO8 for Water Oxidation via Surface Reconstruction

Kai Zeng; Haiyang Yu; Zhihui Sun; Jin Yan; Xiangjun Zheng; Yongxiang Jiang; Wanlu Hu; Jing-Hua Tian; Ruizhi Yang

doi:10.1021/acsami.0c10678

Enhanced Electrocatalytic Activity of Murdochite-Type Ni₆MnO₈ for Water Oxidation via Surface Reconstruction

ACS Appl Mater Interfaces. 2020 Sep 2;12(35):39205-39214. doi: 10.1021/acsami.0c10678. Epub 2020 Aug 21.

Authors

Kai Zeng^{1

2}, Haiyang Yu^{1

2}, Zhihui Sun^{1

2}, Jin Yan^{1

2}, Xiangjun Zheng^{1

2}, Yongxiang Jiang^{1

2}, Wanlu Hu^{1

2}, Jing-Hua Tian^{1

2}, Ruizhi Yang^{1

2}

Affiliations

¹ College of Energy, Soochow Institute for Energy and Materials Innovations, Soochow University, Suzhou 215006, China.
² Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou 215006, China.

PMID: 32805897
DOI: 10.1021/acsami.0c10678

Abstract

Ni-Mn-based binary oxides are deemed as prospective electrocatalysts for water oxidation. Here, a murdochite-type Ni₆MnO₈ electrocatalyst for water oxidation is reported. Murdochite-type Ni₆MnO₈ with hollow sphere (NMO-HS) and microflower (NMO-MF) structures has been controllably synthesized. After an in-situ activation process, the NMO-MF affords a superior activity for oxygen evolution reaction in 0.1 M KOH. A low overpotential of 370 mV at 10 mA cm^-2 is obtained, and the mass activity of activated NMO-MF is 1.96 times that of commercial IrO₂/C. As revealed by in-situ Raman spectra, Ni species in activated NMO-MF act as intrinsic active sites, and the in-situ formed NiOOH on the surface during the activation process is identified to contribute to the significantly enhanced catalytic activity. The Zn-air battery assembled with a NMO-MF cathode showed an exceptional power density (0.228 W cm^-2) and long-term cycling stability (148 h).

Keywords: Zn−air battery; active sites; in-situ activation; murdochite-type Ni6MnO8; oxygen evolution reaction.