ZIF-67 Derived Cu-Doped Electrocatalyst for Oxygen Reduction Reaction
Muhammad Daarain Haider, Naseem Iqbal, Syed Aun M. Rizvi, Tayyaba Nооr, Saadia Hanif, Rehan Anwar
Abstract
Abstract In the present study, the catalytic activity of copper-loaded cobalt-based metal–organic framework (ZIF-67) composites was studied for their electrochemical oxygen reduction reaction (ORR). The Cu-ZIF-67 composite was prepared by the solvothermal method. After pyrolysis under argon atmosphere at 700 °C, the composite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). The electrochemical activity of the composites was tested for ORR in 0.1 M alkaline media using the three-electrode system by cyclic voltammetry (CV), Tafel plots, and electrochemical impedance spectroscopy (EIS). The composites showed variable activity with a current density of 1.32 mA cm−2 at 0.71 V (versus reversible hydrogen electrode (RHE)) onset potential for 70 wt% Cu-ZIF-67, 7.5 mA cm−2 at 0.82 V (versus RHE) onset potential for 50 wt% Cu-ZIF-67, and 11.85 mA cm−2 at 0.85 V (versus RHE) for 30% Cu-ZIF-67. The increasing ratio of the ZIF-67 effect can be attributed to the increased activity of ZIF-67 with the synergistic effect of Cu toward increased current density.