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Nano Research

Article Title

In situ construction of porous hierarchical (Ni3-xFex)FeN/Ni heterojunctions toward efficient electrocatalytic oxygen evolution

Authors

Minglei Yan, Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
Kun Mao, Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
Peixin Cui, Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
Chi Chen, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
Jie Zhao, Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
Xizhang Wang, Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
Lijun Yang, Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
Hui Yang, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
Qiang Wu, Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
Zheng Hu, Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Laboratory of Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China

Keywords

oxygen evolution reaction, electrocatalysts, ternary Ni-Fe nitrides, heterojunctions, in situ construction

Abstract

As a choke point in water electrolysis, the oxygen evolution reaction (OER) suffers from the severe electrode polarization and large overpotential. Herein, the porous hierarchical hetero-(Ni3−xFex)FeN/Ni catalysts are in situ constructed for the efficient electrocatalytic OER. X-ray absorption fine structure characterizations reveal the strong Ni–Fe bimetallic interaction in (Ni3−xFex)FeN/Ni. Theoretical study indicates the heterojunction and bimetallic interaction decrease the free-energy change for the rate-limiting step of the OER and the overpotential thereof. In addition, the high conductivity and porous hierarchical morphology favor the electron transfer, electrolyte access and O2 release. Consequently, the optimized catalyst achieves a low overpotential of 223 mV at 10 mA·cm−2, a small Tafel slope of 68 mV·dec−1, and a high stability. The excellent performance of the optimized catalyst is also demonstrated by the overall water electrolysis with a low working voltage and high Faradaic efficiency. Moreover, the correlation between the structure and performance is well established by the experimental characterizations and theoretical calculations, which confirms the origin of the OER activity from the surface metal oxyhydroxide in situ generated upon applying the current. This study suggests a promising approach to the advanced OER electrocatalysts for practical applications by constructing the porous hierarchical metal-compound/metal heterojunctions.

Graphical Abstract

Publisher

Tsinghua University Press

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