Metal organic framework-derived Ni/Zn/Co/NC composites as efficient catalyst for oxygen evolution reaction

Electrocatalytic water splitting to acquire hydrogen has been recognized as one of the most promising routes to solve the energy crisis and environmental issues. In this paper, we adopted the facile cocrystallization technique to synthesize the ZIF-8/ZIF-67 and used it as support to prepare Ni/ZIF-8/ZIF-67. After being annealed at 800 °C, Ni/ZIF-8/ZIF-67 was successfully transformed into Ni/Zn/Co/NC electrocatalyst (NC is the abbreviation of nitrogen-doped graphitic carbon). The structures and properties of all as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM). The oxygen evolution reaction (OER) activity was evaluated in a standard three-electrode electrochemical cell in alkaline solution (1 M KOH solution). The results show that the doping of Ni and Zn has great influence on the OER activity of Co/NC electrocatalyst. Compared with Co/NC (1.63 V) and Zn/Co/NC (1.58 V), Ni/Zn/Co/NC exhibits the highest OER activity (1.53 V). Except that, Ni/Zn/Co/NC has high stability. After 10 h of continuous operation at a static potential of 1.52 V for 10 h, it just shows 4.0% of decay.