Increased nucleation sites in nickel foam for the synthesis of MoP@Ni3P/NF nanosheets for bifunctional water splitting

Fabricating low-overpotential materials for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an important component of current developments in clean energy. Here, we use nickel oxide for its high hydrophilicity and ammonium fluoride to cause the current collector to produce more active sites with increased adhesion to prepare 2D ultrafine Mo-based precursor nanosheets with uniform dimensions and a stable structure on nickel foam (NF). Further phosphorization treatment is performed to obtain porous molybdenum phosphide (MoP) nanosheets on Ni₃P/NF. As a freestanding integrated electrode, MoP@Ni₃P/NF possess excellent catalytic activity for the HER and OER with low overpotentials (45 mV to reach 10 mA cm⁻² for the HER and 331 mV to reach 35 mA cm⁻² for the OER). The performance of this catalyst is close to that of some precious metal catalysts. The activity as both an anode and cathode catalyst for overall water splitting can reach 1.67 V at 10 mA cm⁻². Due to its scalable preparation and stability, the MoP@Ni₃P/NF electrocatalyst is promising for use in practical water-alkali electrolysis.