Self-supporting and hierarchically porous NixFe–S/NiFe2O4 heterostructure as a bifunctional electrocatalyst for fluctuating overall water splitting

Wenjing Yan; Jintao Zhang; Aijing Lü; Songle Lu; Yiwei Zhong; Mingyong Wang

doi:10.1007/s12613-022-2443-2

Volume 29 Issue 5

Apr. 2022

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Article Navigation > International Journal of Minerals, Metallurgy and Materials > 2022 > 29(5): 1120-1131

Wenjing Yan, Jintao Zhang, Aijing Lü, Songle Lu, Yiwei Zhong, and Mingyong Wang, Self-supporting and hierarchically porous Ni_xFe–S/NiFe₂O₄ heterostructure as a bifunctional electrocatalyst for fluctuating overall water splitting, Int. J. Miner. Metall. Mater., 29(2022), No. 5, pp. 1120-1131. https://doi.org/10.1007/s12613-022-2443-2

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Wenjing Yan, Jintao Zhang, Aijing Lü, Songle Lu, Yiwei Zhong, and Mingyong Wang, Self-supporting and hierarchically porous NixFe–S/NiFe2O4 heterostructure as a bifunctional electrocatalyst for fluctuating overall water splitting, Int. J. Miner. Metall. Mater., 29(2022), No. 5, pp. 1120-1131. https://doi.org/10.1007/s12613-022-2443-2

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Research Article

Self-supporting and hierarchically porous Ni_xFe–S/NiFe₂O₄ heterostructure as a bifunctional electrocatalyst for fluctuating overall water splitting

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Corresponding authors:
Yiwei Zhong E-mail: ywzhong@ustb.edu.cn

Mingyong Wang E-mail: mywang@ustb.edu.cn
Received: 11 December 2021; Revised: 28 January 2022; Accepted: 21 February 2022; Available online: 23 February 2022

Abstract

Abstract

Stable non-noble metal bifunctional electrocatalysts are one of the challenges to the fluctuating overall water splitting driven by renewable energy. Herein, a novel self-supporting hierarchically porous Ni_xFe–S/NiFe₂O₄ heterostructure as bifunctional electrocatalyst was constructed based on porous Ni–Fe electrodeposition on three-dimensional (3D) carbon fiber cloth, in situ oxidation, and chemical sulfuration. Results showed that the Ni_xFe–S/NiFe₂O₄ heterostructure with a large specific surface area exhibits good bifunctional activity and stability for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) because of the abundance of active sites, synergistic effect of the heterostructure, superhydrophilic surface, and stable, self-supporting structure. The results further confirmed that the Ni_xFe–S phase in the heterostructure is transformed into metal oxides/hydroxides and Ni₃S₂ during OER. Compared with the commercial 20wt% Pt/C||IrO₂–Ta₂O₅ electrolyzer, the self-supporting Ni_1/5Fe–S/NiFe₂O₄||Ni_1/2Fe–S/NiFe₂O₄ electrolyzer exhibits better stability and lower cell voltage in the fluctuating current density range of 10–500 mA/cm². Particularly, the cell voltage of Ni_1/5Fe–S/NiFe₂O₄||Ni_1/2Fe–S/NiFe₂O₄ is only approximately 3.91 V at an industrial current density of 500 mA/cm², which is lower than that of the 20wt% Pt/C||IrO₂–Ta₂O₅ electrolyzer (i.e., approximately 4.79 V). This work provides a promising strategy to develop excellent bifunctional electrocatalysts for fluctuating overall water splitting.
- self-supporting;
- hierarchically porous structure;
- heterostructure;
- bifunctional catalyst;
- overall water splitting

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