A Convenient Method for Synthesis of Fe3O4/FeS2 as High-Performance Electrocatalysts for Oxygen Evolution Reaction and Zinc-Air Batteries

The development of highly efficient and inexpensive electrocatalysts has attracted great attention due to the large demand for renewable energy conversion devices. Magnetite-based electrocatalyst, which is stable in natural environment, has been widely considered as one of the most promising candidates. However, its electrocatalytic performance is still unsatisfactory because it has the characteristics of large resistance and large energy barriers to form intermediate species during water oxidation. In this report, we demonstrate a convenient method to synthesize Fe3O4/FeS2 NP catalyst from MIL-101(Fe) for oxygen evolution reaction and zinc-air batteries. The Fe3O4/FeS2 NP catalyst shows outstanding activity with lower overpotential of 265 mV to reach the current density of 10 mA cm−2, which is better than or comparable to the recently reported Fe-based or Co-based catalysts. Systematic research reveals that thus enhancement can be ascribed to the increase of electrochemically active surface areas and the decrease of bonding energy of intermediates. Based on thus novel Fe3O4/FeS2 NP electrodes, the as-prepared zinc-air batteries can achieve specific capacity of around 560 mAh gZn −1 and impressive cyclic stability. It is believed that these findings would help us to develop high-performance and sustainable electrocatalysts.