In situ growth of volcano-like FeIr alloy on nickel foam as efficient bifunctional catalyst for overall water splitting at high current density

Developing active and durable catalysts for water splitting is challenging, especially at high current density. Herein, unique volcano-like FeIr alloy self-supported on nickel foam (NF) is prepared by hydrothermal process. It only needs overpotentials of 220.0 and 25.6 mV for oxygen and hydrogen evolution reaction (OER, HER) at ± 10 mA cm−2 in 1.0 M KOH, and both of them can keep for 124 h at ± 1,000 mA cm−2. For overall water splitting, 1.51 and 1.75 V are needed to reach 10 and 500 mA cm−2, and it can work at 500 mA cm−2 for 100 h in 30 wt% KOH solution at 60 °C. This can be due to the self-supporting volcano-like FeIr alloy structure, which can enhance the HER/OER intrinsic activity, and it is good for bubbles release to improve the stability. Thus, this work provides a strategy for developing efficient catalyst towards water splitting.