Amorphous Nanocages of Cu‐Ni‐Fe Hydr(oxy)oxide Prepared by Photocorrosion For Highly Efficient Oxygen Evolution

: Electrochemical water splitting requires efficient, low-cost water oxidation catalysts to accelerate the sluggish kinetics of the water oxidation reaction. A rapid photocorrosion method is now used to synthesize the homogeneous amorphous nanocages of Cu-Ni-Fe hydr(oxy)oxide as a highly efficient electrocatalyst for the oxygen evolution reaction (OER). The as-fabricated product exhibits a low overpotential of 224 mV on a glassy carbon electrode at 10 mA cm-2 (even lower down to 181 mV when supported on Ni foam) with a Tafel slope of 44 mV dec-1 for OER in an alkaline solution. The obtained catalyst shows an extraordinarily large mass activity of 1464.5 A g-1 at overpotential of 300 mV, which is the highest mass activity for OER. This synthetic strategy may open a brand new pathway to prepare copper-based ternary amorphous nanocages for greatly enhanced oxygen evolution.