Biomolecule‐Assisted Synthesis and Electrochemical Hydrogen Storage of Porous Spongelike Ni3S2 Nanostructures Grown Directly on Nickel Foils

Abstract

Nanothread-based porous spongelike Ni₃S₂ nanostructures were synthesized directly on Ni foil by using a simple biomolecule-assisted method. By varying the experimental parameters, other novel Ni₃S₂ nanostructures could also be fabricated on the nickel substrate. The electrochemical hydrogen-storage behavior of these novel porous Ni₃S₂ nanostructures was investigated as an example of the potential properties of such porous materials. The thread-based porous spongelike Ni₃S₂ could electrochemically charge and discharge with the high capacity of 380 mAh g⁻¹ (corresponding to 1.4 wt % hydrogen in single-walled nanotubes (SWNT)). A novel two-charging-plateaux phenomenon was observed in the synthesized porous spongelike Ni₃S₂ nanostructures, suggesting two independent steps in the charging process. We have demonstrated that the morphology of the synthesized Ni₃S₂ nanostructures had a noticeable influence on their electrochemical hydrogen-storage capacity. This is probably due to the size and density of the pores as well as the microcosmic morphology of different nickel sulfide nanostructures. These novel porous Ni₃S₂ nanostructures should find wide applications in hydrogen storage, high-energy batteries, luminescence, and catalytic fields. This facile, environmentally benign, and solution-phase biomolecule-assisted method can be potentially extended to the preparation of other metal sulfide nanostructures on metal substrates, such as Cu, Fe, Sn, and Pb foils.