Metal-organic framework-derived M (M = Fe, Ni, Zn and Mo) doped Co9S8 nanoarrays as efficient electrocatalyst for water splitting: The combination of theoretical calculation and experiment

Doping metal ions into sulfide is a promising strategy to improve water splitting activity. Here, first-principles theoretical calculations according to density functional theory (DFT) combined with experimental research is researched to develop different transition metals ions (M = Fe, Ni, Zn and Mo) doped into Co9S8 (M-Co9S8) for enhancing overall water splitting activity. The DFT calculation results predict that Ni–Co9S8/NF displays improved electrochemical activity for water splitting. The different transition metal ions (M = Fe, Ni, Zn and Mo) doped into Co9S8 (M-Co9S8) are prepared for the first time by simple hydrothermal and sulfuration process. Only 1.45 V of cell voltages of Ni–Co9S8/NF is required to drive 10 mA cm−2, which is one of the smallest cell voltages reported. These experimental results are highly consistent with the DFT calculations predictions. This work offers a significative methodology and theoretical evaluation to develop a highly efficient electrocatalyst for practical water splitting applications.