Dendritic Fe_0.64Ni_0.36/FeOOH Application for the Decomposition of High-Concentration Alkaline Seawater

Abstract

The design and development of nonprecious metal-based bifunctional electrocatalysts are important for development of the catalytic electrolysis of seawater for hydrogen production in industrial environments. Here, we report the preparation of dendritic structured catalysts on copper foam using a simple one-step cathodic deposition method. The higher the KOH concentration in the electrolyte, the better for the HER and OER reactions. The optimal electrocatalyst CuNiFe1@CF requires only low overpotentials of 240 and 320 mV for HER and OER at the current density of 500 mA·cm–2, respectively. Building the electrolytic cell revealed that it also requires only 1.56 V at a commercially practical current density of 500 mA·cm–2 and provides significant stability over 30 h, offering great potential for large-scale applications. This excellent performance should be attributed to the unique dendritic structure resisting the corrosion of Cl–, the dendritic as a skeleton surface covered with a large number of nanosheets of Fe0.64Ni0.36/FeOOH exposing more catalytically active sites. In this work, it is demonstrated that increasing the KOH concentration can effectively enhance the rate of seawater electrolysis and that the dendritic structure catalyst as a natural chloride ion blocking layer significantly improves the activity and stability of seawater electrolysis. It provides a new design idea for low-cost bifunctional seawater electrolysis electrocatalysts, which is of great significance for industrial development in the field of hydrogen energy.