Cobalt vanadate as highly active, stable, noble metal-free oxygen evolution electrocatalyst

Abstract

Water splitting, to produce hydrogen and oxygen, has long been considered to be a desirable option for the storage of electrical energy. The catalysts for oxygen evolution reactions (OER) are very important in this process. Herein, we have synthesized Co₃V₂O₈ nanoparticles by a simple and cost-effective technique, which have low crystallinity and large specific surface area (122.8 m² g⁻¹). Because of the low crystallinity, large specific surface area and suitable pore size, Co₃V₂O₈ nanoparticles yielded an electrocatalytic OER current density of up to 429.7 mA cm⁻² at 2.05 V vs. RHE and low OER over potentials of 359 mV (at 10 mA cm⁻²) and 497 mV (at 100 mA cm⁻²). In addition, the OER stability of the Co₃V₂O₈ catalyst was very excellent, and the current density at 2.05 V was reduced by just 7.3% after galvanostatic OER measurement at 10 mA cm⁻² for 3 h. This work demonstrates that binary metal oxides Co₃V₂O₈ is a highly active and stable oxygen evolution electrocatalyst that can potentially replace expensive noble metal-based anode catalysts for electrochemical water splitting to generate hydrogen fuels.