Large-Area Synthesis of a Ni₂P Honeycomb Electrode for Highly Efficient Water Splitting

Transition metal phosphides have recently been regarded as robust, inexpensive electrocatalysts for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Thus far, tremendous scientific efforts have been applied to improve the catalytic activity of the catalyst, whereas the scale-up fabrication of morphology-controlled catalysts while maintaining their desired performance remains a great challenge. Herein, we present a facile and scalable approach to fabricate the macroporous Ni₂P/nickel foam electrode. The obtained electrocatalyst exhibits superior bifunctional catalytic activity and durability, as evidenced by a low overpotential of 205 and 300 mV required to achieve a high current density of 100 mA cm^-2 for HER and OER, respectively. Such a spray-based strategy is believed to widely adapt for the preparation of electrodes with uniform macroporous structures over a large area (e.g., 100 cm²), which provides a universal strategy for the mass fabrication of high performance water-splitting electrodes.