Rapidly synthesized porous alloy heterostructure catalysts for ultra-low energy water splitting under industrial conditions

Abstract

RANEY® nickel is extensively applied in industrial settings for its low cost and ease of scale-up. Nevertheless, its poor activity and high energy consumption restrict the progress of large-scale hydrogen production. Here, we used a RANEY® nickel substrate combined with a one-step electrodeposition method to prepare porous NiFe@RN bifunctional catalysts. The results show excellent catalytic activity in both the HER and OER, with overpotentials of 93.51 and 248 mV, respectively, at a current density of 100 mA cm⁻². In industrial settings, the NiFe@RN assembled dual-electrode electrolyzer requires only 1.68 V to drive a current density of 500 mA cm⁻², demonstrating excellent stability for 20 hours. Simultaneously, this study also found that the synergistic effect of Ni⁰, Fe⁰, and the NiFeOOH heterostructure can significantly enhance the electrode's catalytic activity and stability. At a current density of 500 mA cm⁻², the energy consumption of hydrogen is only 3.998 kW h m⁻³ H₂, which is 19.8% lower than the existing industrial catalysts (4.79 kW h m⁻³ H₂). Compared to the current hydrogen production in factories, producing one million tons of hydrogen is expected to save up to 8.87 billion kW h of energy, achieving ultra-low energy consumption in hydrogen production. The catalyst prepared in this study exhibits remarkable catalytic activity under industrial conditions, reducing the energy consumption of industrial-grade electrolytic water, and provides a new perspective for preparing efficient bifunctional electrocatalysts with porous structures on an industrial scale in the future.