Chinese Journal of Catalysis ›› 2022, Vol. 43 ›› Issue (5): 1267-1276.DOI: 10.1016/S1872-2067(21)63962-1

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Sea urchin-like NiMoO4 nanorod arrays as highly efficient bifunctional catalysts for electrocatalytic/photovoltage-driven urea electrolysis

Chenxin Chena, Suqi Hea, Kamran Dastafkanb, Zehua Zoua, Qingxiang Wanga(), Chuan Zhaob()   

  1. aDepartment of Chemistry and Environment Science, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, Fujian, China
    bSchool of Chemistry and Materials & Manufacturing Futures Institute, The University of New South Wales, Sydney 2052, Australia
  • Received:2021-09-15 Accepted:2021-10-22 Online:2022-05-18 Published:2022-03-23
  • Contact: Qingxiang Wang, Chuan Zhao
  • Supported by:
    Future Fellow from Australian Research Council(FT170100224);National Natural Science Foundation of China(21275127);Natural Science Foundation of Fujian Province(2018J01435)

Abstract:

Developing multifunctional electrocatalysts with high catalytic activity, long-term stability, and low cost is essential for electrocatalytic energy conversion. Herein, sea urchin-like NiMoO4 nanorod arrays grown on nickel foam has been developed as a bifunctional electrocatalyst for urea oxidation and hydrogen evolution. The NiMoO4-200/NF catalyst exhibits efficient activity toward hydrogen evolution reaction with a low overpotential of only 68 mV in 1.0 mol/L KOH to gain a current density of 10 mA cm-2. The NiMoO4-300/NF catalyst exhibits a prominent oxygen evolution reaction (OER) catalytic activity with an overpotential of 288 mV at 50 mA cm-2, as well as for urea oxidation reaction with an ultra-low potential of 1.36 V at 10 mA cm-2. The observed difference in electrocatalytic activity and selectivity, derived by temperature variation, is ascribed to different lattice oxygen contents. The lattice oxygen of NiMoO4-300/NF is more than that of NiMoO4-200/NF, and the lattice oxygen is conducive to the progress of OER. A urea electrolyzer was assembled with NiMoO4-200/NF and NiMoO4-300/NF as cathode and anode respectively, delivering a current density of 10 mA cm-2 at a cell voltage of merely 1.38 V. The NiMoO4 nanorod arrays has also been successfully applied for photovoltage-driven urea electrolysis and hydrogen production, revealing its great potential for solar-driven energy conversion.

Key words: NiMoO4 nanorod, Bifunctional electrocatalyst, Urea electrolysis, Photovoltage-driven, Lattice oxygen, Sea urchin-like