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Abstract Electrochemical science and technology can play a vital role for the indirect storing of extra renewable energy through converting the electricity into chemical energy. This may participate in solving the global problem of consuming the irrecoverable fossil fuels.For instance, water splitting into hydrogen and oxygen by electrolysis is considered as a hopeful substitute to electricity storage systems using batteries. Recently, many intensive studies focused on constructing high efficient and low cost electrocatalysts mostly for water splitting reactions: oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). This work involves the following: 1. Many cobalt/graphite electrodes were successfully prepared via chronoamperometry deposition of cobalt from bath containing Co+2 ions in the absence and presence of equimolar concentration of citrate ions on graphite substrate. As graphite is considered as a typical electrocatalyst support in various energy conversion and storage devices such as fuel cells, supercapacitors, lithium ion batteries and water splitting reactions (OER and HER).2. The electrodepostion processe was studied using eQCM technique, and the morphology of all prepared electrodes was evidenced using XRD and FESEM techniques. 3. All prepared electrodes were electrochemical charctrised using cyclic voltammetry (CV), chronopotniometry and electrochemical impedance spectroscopy (EIS) techniques. 4. The electrochemical behaviour of the prepared electrodes were investigated as electrocatalyst toward OER in 1M NaOH solution and the corelation between their surface structure and electrochemical activity has been extensively discussed. 5. It has been concluded that the presence of citrate ions in the electrodeposition bath favors the instantaneous nucleation of Co speceis deposition rather than the progressive nucleation, leading to form a more uniform cobalt speceis film on the graphite substrate. This was confirmed by XRD, FESEM and EIS techniques. Therefore, the Cobalt/graphite electrode prepared from citrate bath displayed an enhanced electrocatalytic activity toward OER. 6. Extra catalytic activity were gained by Co-Cit/G electrode via successive potentiodynamic polarization in 1M NaOH solution. 7. Moreover, the chronopotentiometry (potential-time), at constant current density stability test for 2 h, as recommended in the literature benchmark, showed a superior stability of Co-Cit/G electrode toward OER in alkaline medium. |