Fe3O4/CoO Interfacial Nanostructure Supported on Carbon Nanotubes as a Highly Efficient Electrocatalyst for Oxygen Evolution Reaction

Transitional metal oxides (TMO) exhibit well electrocatalytic performance for oxygen evolution reaction (OER) and have the potential to replace the noble metal electrocatalysts. However, how to further increase the number of catalytic active sites and improve the electrocatalytic activity in alkaline solution is always a great challenge. Therefore, it is necessary to develop high-performance OER electrocatalysts. Herein, the coupled interfacial nanostructure of Fe3O4 and CoO was successfully supported on carbon nanotubes (CNTs) as a highly efficient OER electrocatalyst (denoted as Fe3O4/CoO CNTs) through a simple and feasible two-step synthesis strategy. It is found that the electrocatalyst Fe3O4/CoO CNTs shows remarkable electrocatalytic activity toward OER with a low overpotential of 270 mV (i.e., 1.50 V vs reversible hydrogen electrode) at the current density of 10 mA cm–2 and a small Tafel slope of 59 mV dec–1 in basic media. Additionally, it presents superior electrochemical stability for over 45 h. The outstanding OER performance of the electrocatalyst is mainly derived from the coupled interfacial nanostructure between Fe3O4 and CoO, which promotes the improvement of the electronic structure, increases the number of catalytic active sites, and creates abundant oxygen vacancies. Our work provides a good choice for the future application of TMO-based electrocatalysts in water splitting.