Hollow Structure Derived Phosphide Nanosheets for Water Oxidation

Avoiding the stacking of active sites in catalyst structural design is a promising route for realizing active oxygen evolution reaction (OER). Herein, using a CoFe Prussian blue analoge cube with hollow structure (C-CoFe PBA) as a derived support, a highly effective Ni₂P-FeP₄-Co₂P catalyst with a larger specific surface area is reported. Benefiting from the abundant active sites and fast charge transfer capability of the phosphide nanosheets, the Ni₂P-FeP₄-Co₂P catalyst in 1 m KOH requires only overpotentials of 248 and 277 mV to reach current density of 10 and 50 mA cm^-2 and outperforms the commercial catalyst RuO₂ and most reported non-noble metal OER catalysts. In addition, the two-electrode system consisting of Ni₂P-FeP₄-Co₂P and Pt/C is able to achieve a current density of 10 and 50 mA cm^-2 at 1.529 and 1.65 V. This work provides more ideas and directions for synthesizing transition metal catalysts for efficient OER performance.