Impact of graphene incorporation on the oxygen evolution reaction of Co-Fe-based electrocatalysts synthesized via one-step electrodeposition.

The oxygen evolution reaction (OER) presents a major challenge for water splitting due to its slow kinetics. In this study, Co-Fe-Gr nanocomposite coatings were developed on carbon steel via electrodeposition using graphene (Gr) at concentrations of 0.02, 0.04, and 0.06 g/L to enhance OER performance. The sample with 0.02 g/L Gr exhibited a unique cauliflower-like morphology with aligned cobalt, as revealed by FE-SEM, leading to an increased electrochemical surface area. This optimal nanocomposite (Co-Fe-Gr (0.02 g/L)) demonstrated a low overpotential of 88 mV at 10 mA cm2, high stability (4.2 mF cm⁻2), and low resistance (R = 7.5 Ω cm⁻2). Additionally, it showed a small Tafel slope of 6.6 mV/dec and maintained stability after 12 h. A turnover frequency (TOF) of 73.6 s⁻1 indicated that graphene doping significantly reduced the adsorption energy of intermediates, greatly enhancing OER activity for efficient water splitting applications. [Display omitted] • Co-Fe-Gr nano-composite electrocatalysts were fabricated using an electrodeposition process. • Increasing the Gr content increased the Gr sheets and reduced the number of active sites. • The Co-Fe-Gr (0.02 g/L) with cauliflower-like morphology had an electrochemically active surface. • The Co-Fe-Gr (0.02 g/L) nano-composite showed the highest electrocatalytic activity. [ABSTRACT FROM AUTHOR]