Two‐Phase Colloidal Synthesis of Amorphous Iron‐Doped Manganese Phosphate Hollow Nanospheres for Efficient Water Oxidation

Abstract Exploitation of earth‐abundant, efficient and stable electrocatalysts is of great significance for the oxygen evolution reaction (OER). Herein, a facile two‐phase colloidal method is developed to synthesize amorphous iron‐doped manganese phosphate (a‐Fe‐Mn:Pi) hollow nanospheres for the first time. Due to the synergistic interplay of hollow nanosphere morphology, amorphous structural character, and iron doping, the a‐Fe‐Mn:Pi catalyst possesses high electrochemically active surface area and excellent conductivity. As a consequence, the obtained a‐Fe‐Mn:Pi sample displays superior OER activity in alkaline condition with a small overpotential of 252 mV at 10 mA cm⁻² and a Tafel slope of 52.0 mV decade⁻¹ as well as 93.3% retention of the initial current density even after 20 h of reaction time. This work provides a new perspective on the design of hollow nanostructures for catalytic applications.