Insights of enhanced oxygen evolution reaction of nanostructured cobalt ferrite surface

The present study includes the process to tune the morphology of CoFe 2 O 4 nanostructures via hydrothermal route and their effect on oxygen evolution reaction (OER). The control of size and morphology has been done via the pH and varying hydrothermal reaction time. Transmission electron microscopy reveals the formation of ~ 20 nm CoFe 2 O 4 nanocube after 24 h reaction time. As-prepared samples deposited over graphite substrate and used as a working electrode for catalysis. CoFe 2 O 4 nanocubes offer better O 2 evolution activity in terms of current density (48 mAcm −2 ), lower onset potential ( η 1 = 260 mV) and overpotential ( η 10 = 430 mV) compared to nanoparticles. The low Tafel slope value (44 mVdec −1 ) of CoFe 2 O 4 nanocube confirms the faster kinetics compared to CoFe 2 O 4 nanoparticles. The effect of electrochemical active surface area, roughness factor ( R f ), wettability properties and surface-active species on the OER performance has been studied. Graphical abstract