Fe 1- x Ni x (PO 3 ) 2 /Ni 2 P Heterostructure for Boosting Alkaline Oxygen Evolution Reaction in Fresh Water and Real Seawater at High Current Density.

Oxygen evolution reaction (OER) is a limiting reaction for highly efficient water electrolysis. Thus, the development of cost-effective and highly efficient OER catalysts is the key to large-scale water electrolysis for hydrogen production. Herein, by using an interfacial engineering strategy, a unique nanoflower-like Fe 1- x Ni x (PO 3 ) 2 /Ni 2 P/NF heterostructure with abundant heterogeneous interfaces is successfully fabricated. The catalyst exhibits excellent OER catalytic activity in alkaline fresh water and alkaline natural seawater at high current densities, which only, respectively, requires overpotentials of 318 and 367 mV to drive 1000 mA cm -2 in fresh water and natural seawater both containing 1 M KOH. Furthermore, Fe 1- x Ni x (PO 3 ) 2 /Ni 2 P/NF demonstrates excellent durability, which can basically remain stable for 80 h during the electrocatalytic OER processes, respectively, in alkaline fresh water and natural seawater. This work provides a new construction strategy for designing highly efficient electrocatalysts for OER at high current densities both in alkaline fresh water and in natural seawater.