Amorphous Multimetal Alloy Oxygen Evolving Catalysts
Weizheng Cai, Hongbin Yang, Junming Zhang, Hsiao‐Chien Chen, Hua Bing Tao, Jiajian Gao, Song Liu, Wei Liu, Xuning Li, Bin Liu
Abstract
The oxygen evolution reaction (OER) is crucial in water electrolysis and metal–air battery and demands a low cost, efficient, and durable electrocatalyst. An ideal OER catalyst should possess optimal bindings to oxygenated intermediates, neither too strong nor too weak; however, the-state-of-the-art earth-abundant 3d first-row transition-metal-based OER catalysts still operate at overpotentials significantly above the thermodynamic equilibrium. In this work, we report a facile room temperature synthesis to prepare homogeneously dispersed, amorphous 3d multi-transition-metal alloys with tunable bindings to oxygenated species. The NiFeMoB alloy with near-optimal oxygenated intermediates adsorption energy exhibits the lowest OER overpotential of only 220 mV (with 95% solution resistance correction) at 500 mA/cm2 on nickel foam in an alkaline electrolyte, which shows no evidence of degradation at this current density following 40 h of continuous operation. By coupling an amorphous NiFeMoB oxygen-evolving anode with a crystalline NiB hydrogen-evolving cathode, we successfully demonstrate an alkaline water electrolysis cell that can be stably operated at a current density of 500 mA/cm2 with input voltage (without solution resistance correction) only around 1.72 V in 1 M KOH at room temperature and 1.57 V in 6 M KOH at 80 °C.