Controllable synthesis of one-dimensional NiS2 nanotube and nanorod arrays on nickel foams for efficient electrocatalytic water splitting

One-dimensional NiS₂ nanotube arrays and nanorod arrays are controllably grown on Ni foam surface. The electrocatalytic test shows that the NiS₂ nanotube arrays require competitive overpotentials of 209 mV for HER and 367 mV for OER (to achieve a current density of 50 mA/cm²), respectively, which are much lower than the NiS₂ nanorod arrays and other NiS₂ nanostructures reported before. Specifically, the NiS₂ nanotube arrays can be employed as an efficient bi-functional catalyst for overall water splitting, with a low cell voltage (1.58 V) to deliver a current density of 10 mA/cm². The outstanding performance can be attributed to the special structural characteristics of nanotubes, which have high specific surface areas along with abundant active sites. The present study not only enriches the morphology of NiS₂ nanostructures for highly efficient electrocatalytic reaction, but also provides an interesting self-assembly path for the synthesis of one-dimensional NiS₂ nanostructures.