NiCoFe layered mixed hydroxides containing same iron composition, but Co/Ni ratios of 1:1, 2:1 and 1:2 were prepared by co-precipitation method and evaluated according to their performance for electrochemical oxygen evolution reaction (OER) or water splitting process. Crystalline phase without impurities was verified by XRD, FTIR, TEM and Mossbauer techniques. From Tafel plots, values of 65 and 110 mV dec(-1) at low and high potential, respectively, were obtained; all electrocatalysts showed lower overpotentials around 265 mV, and sample Ni3Co3Fe3 with equimolar composition ratio exhibited the best performance (lowest overpotential 250 mV). Cobalt in low-spin configuration has effect on the electronic properties of brucite layer sheet, modulating the necessary potential for nickel oxidation which acts as active site for water splitting.