CoOx Functionalized IrO2-Sb2O5-SnO2 Anode with An Enhanced Activity and Stability for Electrocatalytic Oxygen Evolution

Preparation of highly efficient and inexpensive electrodes for oxygen evolution reaction (OER) is of significant importance in the development of water splitting for hydrogen production. Ternary IrO2-Sb2O5-SnO2 and cobalt-based oxides have been suggested to be high stability and low cost electrocatalysts for OER in acid and basic aqueous solution, respectively. Herein, we develop a serial of Ti/CoOx-IrO2-Sb2O5-SnO2 anodes by a simple thermal treatment of mixed metal chlorides on Ti substrate. It is found that the partial-substitution iridium by cobalt in Ti/Ir0.1Sb0.1Sn0.8Ox (Ti/C0ISS) anode shows an improved OER activity in acid and basic solution. For a Ti/Ir0.05Co0.05Sb0.1Sn0.8Ox (Ti/C5ISS) anode, small overpotentials of 0.438 and 0.498 V are needed under the current densities of 10 and 100 mA cm−2 in 0.5 M KOH, respectively. These values are remarkably lower than those of Ti/C0ISS electrode and comparable to other nanometer metal oxides catalysts. Additionally, it exhibits a low Tafel slope of 55 mV dec−1 and displays excellent electrocatalytic durability for OER in alkaline solution under a high current density. These advantages indicate Ti/C5ISS is a promising anode for water oxidation under high current densities.