Fe-doped CoNiP@N-doped carbon nanosheet arrays for hydrazine oxidation assisting energy-saving seawater splitting

Hydrazine oxidation assisting seawater splitting is a promising strategy to achieve chlorine-free energy-saving hydrogen production. Herein, Fe-doped Ni2P/CoP encapsulated by ultrathin nitrogen-doped carbon layers (FeCoNiP@NC) with unique nanosheet structure grown on Ni foam are synthesized, which was used as highly efficient and durable bifunctional catalyst for both hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER). For the two-electrode system toward overall hydrazine splitting (OHzS) in alkaline seawater, FeCoNiP@NC reveals a low cell voltage of 0.56 V at 1000 mA cm(-2), stable operation for 100 h to keep ~500 mA cm(-2), and nearly 100% Faraday efficiency. Compared to the N2H4-free seawater system, the OHzS system can save 4.03 kWh for producing 1.0 m(3) of H-2, realizing energy-saving H-2 production.

Automated summary

In this study, a highly efficient and durable bifunctional catalyst FeCoNiP@NC was synthesized for hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER). The catalyst showed low voltage, high stability, and energy-saving hydrogen production in alkaline seawater.