Constructing Multifunctional Heterostructure of Fe₂ O₃ @Ni₃ Se₄ Nanotubes

Heterostructures have attracted increasing attention due to their amazing synergetic effects, which may improve the electrochemical properties, such as good electrical/ionic conductivity, electrochemical activity, and mechanical stability. Herein, novel hierarchical Fe₂ O₃ @Ni₃ Se₄ nanotubes are successfully fabricated by a multistep strategy. The nanotubes show length sizes of ≈250-500 nm, diameter sizes of ≈100-150 nm, and wall thicknesses of ≈10 nm. The as-prepared Fe₂ O₃ @Ni₃ Se₄ nanotubes with I_Ni:Fe = 1:10 show excellent Li storage properties (897 mAh g^-1 high reversible charge capacity at 0.1 A g^-1 ), good rate performance (440 mAh g^-1 at 5 A g^-1 ), and outstanding long-term cycling performance (440 mAh g^-1 at 5 A g^-1 during the 300th cycle) as an anode material for lithium ion batteries. In addition, the Fe₂ O₃ @Ni₃ Se₄ nanotubes with I_Ni:Fe = 1:10 (the atomic ratio between Ni and Fe) show superior electrocatalytic performance toward the oxygen evolution reaction with an overpotential of only 246 mV at 10 mA cm^-2 and a low Tafel slope of 51 mV dec^-1 in 1 m KOH solution.