Fe-Ni co-Doping Strategy in Perovskite for Developing an Efficient Oxygen Evolution Electrocatalyst

The high reaction barrier of the oxygen evolution reaction (OER) has always been the bottleneck of the water decomposition reaction, so low-cost, high-performance and stable catalysts are urgently needed currently. Herein, we designed an effective OER electrocatalyst BaCo_0.6Fe_0.2Ni_0.2O_3−δ (BCFN) by a co-doping strategy. The overpotential of BCFN at a current density of 10 mA/cm² reaches 310 mV, and possesses a Tafel slope of 50.2 mV/dec. The catalytic capability of BCFN is much stronger than that of Fe-doped BaCo_0.8Fe_0.2O_3−δ (360 mV), Ni-doped BaCo_0.8Ni_0.2O_3−δ (375 mV), and benchmark IrO₂ with excellent performance (329 mV). At the same time, BCFN is also a fairly stable alkaline OER catalyst. After 500-cycle scans, BCFN still shows high catalytic activity without significant decrease in catalytic performance. Electrochemical experiments show that BCFN has the fastest reaction kinetics and the lowest charge transfer resistance among the materials in this work. In addition, a large amount of highly oxidative oxygen O₂²⁻/O⁻ and hydroxyl groups OH⁻ on the surface of BCFN are conducive to the occurrence of OER, thereby increasing the reaction rate. This work provides a universal strategy to develop high-performance electrocatalysts for electrochemical energy conversion technology.