Electrochemical impedance spectroscopy study of oxygen evolution reaction on nanosized CoWO 4 and NiWO 4

CoWO 4 and NiWO 4 have been prepared by a co-precipitation method and investigated as electrocatalysts for the oxygen evolution reaction in 1 M KOH by electrochemical impedance spectroscopy. The electrode kinetic parameters such as the electrochemical active surface area, exchange current density, Tafel slope, and the reaction order are determined. Results have shown that the values of the Tafel slope and reaction order obtained from the EIS study excellently match with those determined by dc techniques.