A highly efficient and long-term durable electrocatalyst for oxygen evolution in alkaline seawater by growing Ni1.5Fe1.5B on the NiMoO4 nanorods

Abstract

The development of efficient and stable catalysts for the oxygen evolution reaction (OER) that can function effectively in seawater is crucial for addressing the energy crisis. In this study, a low-cost hydrothermal-dip-coating method was employed to synthesize Ni1.5Fe1.5B nanosheets decorated three-dimensional NiMoO4 nanorods anchored on nickel foam (NiMoO4@Ni1.5Fe1.5B). This catalyst exhibits high conductivity and electrochemically active surface areas, which can be attributed to the synergistic effect between NiMoO4 and Ni1.5Fe1.5B, the presence of numerous oxygen vacancies, and the modification of boron. The NiMoO4@Ni1.5Fe1.5B catalyst exhibits exceptional catalytic activity for the oxygen evolution reaction (OER), as evidenced by overpotentials of 235 and 262 mV required to achieve current densities of 100 and 200 mA cm−2, respectively, in 1 M KOH. Notably, the leaching of Mo during the OER in alkaline conditions contributes to the preservation of the 3D core-shell structure of NiMoO4@Ni1.5Fe1.5B, resulting in improved stability and resistance to chloride-induced corrosion. In seawater with a concentration of 1 M KOH, the catalyst requires overpotentials of 261 and 299 mV to achieve current densities of 100 and 200 mA cm−2, respectively, and can operate continuously for 72 h without significant performance degradation.