Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (11): 1736-1745.DOI: 10.1016/S1872-2067(18)63150-X

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Hierarchical coral-like FeNi(OH)x/Ni via mild corrosion of nickel as an integrated electrode for efficient overall water splitting

Rui Xianga, Cheng Tonga, Yao Wanga, Lishan Penga, Yao Nieb, Li Lia, Xun Huanga, Zidong Weia   

  1. a Chongqing Key Laboratory of Chemical Process for Clean Energy and Resource Utilization, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China;
    b College of Chemistry, Chongqing Normal University, Chongqing 400047, China
  • Received:2018-07-02 Revised:2018-07-31 Online:2018-11-18 Published:2018-09-01
  • Contact: 10.1016/S1872-2067(18)63150-X
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21436003, 21576032).

Abstract:

Efficient, stable, and noble-metal-free electrocatalysts for both the oxygen evolution reaction and the hydrogen evolution reaction are highly imperative for the realization of low-cost commercial water-splitting electrolyzers. Herein, a cost-effective and ecofriendly strategy is reported to fabricate coral-like FeNi(OH)x/Ni as a bifunctional electrocatalyst for overall water splitting in alkaline media. With the assistance of mild corrosion of Ni by Fe(NO3)3, in situ generated FeNi(OH)x nanosheets are intimately attached on metallic coral-like Ni. Integration of these nanosheets with the electrodeposited coral-like Ni skeleton and the supermacroporous Ni foam substrate forms a binder-free hierarchical electrode, which is beneficial for exposing catalytic active sites, accelerating mass transport, and facilitating the release of gaseous species. In 1.0 mol L-1 KOH solution, a symmetric electrolyzer constructed with FeNi(OH)x/Ni as both the anode and the cathode exhibits an excellent activity with an applied potential difference of 1.52 V at 10 mA cm-2, which is superior to that of an asymmetric electrolyzer constructed with the state-of-the-art RuO2-PtC couple (applied potential difference of 1.55 V at 10 mA cm-2). This work contributes a facile and reliable strategy for manufacturing affordable, practical, and promising water-splitting devices.

Key words: Overall water splitting, Electro-catalysis, Fe/Ni hydroxide, Alkaline electrolyser, Integrate electrode