Facile Synthesis of Ni-Co LDH Nanocages with Improved Electrocatalytic Activity for Water Oxidation Reaction

The development of an inexpensive, efficient and robust water oxidation catalyst is important to achieve water splitting for renewable energy production. Herein, nickel-cobalt layered double hydroxides (Ni-Co LDHs) were rationally synthesized by a facile method and can be served as efficient electrocatalysts for water oxidation. For comparison, Ni-Co LDH nanoflowers have also been synthesized by controlling the synthetic process. The composition and morphologies of the catalysts were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The as-obtained Ni-Co LDH nanocages exhibit a high catalytic activity toward the water oxidation reaction (WOR). The electrochemical results show that the overpotential of Ni-Co LDH nanocages electrode was 350 mV at a catalytic current density of 10.0 mA cm -2 in 1.0 M KOH. Moreover, the Tafel slope was as low as ~ 93 mV dec -1 . The unusual catalytic properties of Ni-Co LDH nanocages could be attributed to the hollow structure and the synergetic effect between Ni metal and Co metal.