Three-dimensional porous cobalt ferrite and carbon nanorod hybrid network as highly efficient electrocatalyst for oxygen evolution reaction

It is still challengeable to develop oxygen evolution reaction (OER) electrocatalyst with low cost and high efficiency to accelerate the kinetic of water splitting. Herein, a facile solvothermal method is put forward to synthesize three-dimensional porous cobalt ferrite and carbon nanorod hybrid network constructed by a network of carbon nanorods in which cobalt ferrite nanoparticles are uniformly embedded. The cobalt ferrite and carbon nanorod hybrid electrocatalyst delivers outstanding OER performance, especially a very low onset potential (1.49 V vs. RHE), a very low Tafel slope (38 mV dec⁻¹), and to obtain a current density of 10 mA cm⁻² only requires a very small potential (1.56 V), which is much better than cobalt ferrite, and comparable to RuO₂. Furthermore, it also displays excellent long-term stability under 25 h of chronoamperometric testing. The reason why cobalt ferrite and carbon nanorod hybrid has such superior OER performance stems from the low oxygen coordination and solid-state redox couples of cobalt ferrite, the conductive carbon nanorod skeleton and the unique three-dimensional porous nanoarchitecture, which can not only sustain the high conductivity and structural stability of the hybrid catalyst, but also facilitate the electron/ion transfer and oxygen bubble diffusion and bare more electrochemically active surface sites. This paper proposes a new scheme for the synthesis of non-noble transition metal oxide-based OER electrocatalysts with rationally designed nanoarchitecture and high efficiency.