A self-supported heterogeneous bimetallic phosphide array electrode enables efficient hydrogen evolution from saline water splitting

Hydrogen generation from water splitting is of great prospect for the sustainable energy conversion. However, it is still challenging to explore stable and high-performance electrocatalysts toward hydrogen evolution reaction (HER) from saline water such as seawater due to the chloride corrosion. Herein, we developed a self-supported heterogeneous bimetallic phosphide (Ni₂P-FeP) array electrode that possesses excellent HER performance in alkaline saline water with an overpotential of 89 mV at 10 mA·cm⁻² and long-term stability over 90 h at 200 mA·cm⁻². The analysis showed that the heterostructure between the interfaces of Ni₂P-FeP plays a pivotal role in promoting the activity of catalyst. Moreover, the bimetallic phosphide nanoarrays can be employed as a shield for chlorine-corrosion resistance in the saline water, ensuring the long-term durability of hydrogen generation. When employed for alkaline saline water electrolysis, a current density of 100 mA·cm⁻² is achieved at cell voltage of 1.68 V. This work presents an effective approach for the fabrication of high-performance electrode for HER in alkaline saline environments.