“…Electrochemical impedance spectroscopy (EIS) which is a powerful technique to study the electrode kinetics in HER 17,18 is performed on Pd/NF, Pd/G/NF, and Pd/ZnO/NF and Pd/G/ ZnO/NF in the range of 10 5 to 10 À1 Hz at the open circuit potential with an AC excitation signal of 5 mV in 1 M KOH. Fig.…”