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

Abstract

This work reports a self-supported volcano-like FeIr alloy catalyst with high activity and stability for overall water splitting at high current density. • Volcano-like FeIr alloy catalyst is prepared by hydrothermal method. • It needs low overpotentials for OER (η 10 = 220.0 mV) and HER (η 10 = 25.6 mV). • For overall water splitting, 1.51 V is needed to arrive at 10 mA cm −2 . • For OER and HER, it can maintain at ± 1000 mA cm −2 for 124 h. • It can maintain at 500 mA cm −2 for 100 h in 30 wt.% KOH solution at 60 °C. 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.