Amorphous Multimetal Alloy Oxygen Evolving Catalysts

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.