P-Doped NiFe Alloy-Based Oxygen Evolution Electrocatalyst for Efficient and Stable Seawater Splitting and Organic...

Development of high-performance and inexpensive electrocatalysts for oxygen evolution reaction (OER) at neutral pH is important for direct seawater splitting and organic electrosynthesis but remains challenging due to the sluggish OER kinetics and diverse side reactions inherent to the constituents of working electrolytes. Herein, we report on a P:NiFe electrode, containing P-doped NiFe alloy, as an excellent electrocatalyst for hydrogen evolution reaction (HER) and OER pre-catalyst for efficient OER in both seawater and organic electrolyte for adiponitrile (ADN) electrosynthesis at neutral pH. Fe and P species modulate the coordination environment of nickel sites, which enables the simultaneous formation of OER-active nickel species and FePO_x passivation layer, thus transforming HER-active P:NiFe to OER-active a-P:NiFe. Besides, the redox-dependent interconversion between HER-active P:NiFe and OER-active a-P:NiFe is fast and reversible. Finally, efficient and stable overall seawater-splitting and ADN electrosynthesis at an industrially relevant current density (100 mA cm^-2) in pH-neutral media are also demonstrated.