Electrocatalytic activity of CoFe2O4 thin films prepared by AACVD towards the oxygen evolution reaction in alkaline media

The electrocatalytic behaviour of CoFe2O4 thin films, prepared by aerosol-assisted chemical vapour deposition, towards the oxygen evolution reaction in an alkaline medium is reported. X-ray diffraction and SEM data show that the CoFe2O4 thin films are phase pure and consist of dendrites 0.5-1 μm in diameter rising from the surface with heights ranging from 1 to 3 μm. The CoFe2O4 thin films exhibited an overpotential of 490 mV at a current density of 10 mA cm− 2, and a Tafel slope of 54.2 mV dec− 1. Taking into account the electrochemically active surface area, the intrinsic activity of CoFe2O4 was found to be 1.75 mA cm− 2real at an overpotential of 490 mV. The CoFe2O4 thin films were highly stable and were capable of maintaining catalytic activity for at least 12 h.