Coupling NiSe2-Ni2P heterostructure nanowrinkles for highly efficient overall water splitting

Developing catalysts with high efficiency and low-cost toward overall water splitting is critical for the sustainable energy conversion. Herein, a facile wet-chemical route followed by successive selenization and partial phosphorization treatments is presented to synthesize the heterostructure combining NiSe2 and Ni2P coupled nanowrinkles on Ni foam (NiSe2-Ni2P/NF). DFT calculation results confirm that the NiSe2 coupled with Ni2P in NiSe2-Ni2P/NF can promote the water adsorption process, speeding up the whole catalytic kinetics for overall water splitting. Benefitting from the synergistic effects between NiSe2 and Ni2P, the optimal NiSe2-Ni2P/NF electrode exhibits excellent catalytic performances toward both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. Impressively, for OER such heterogeneous nanowrinkles merely require an ultralow overpotential of 220 mV to reach the current density of 50 mA cm−2. Moreover, when utilized as a bifunctional catalyst for overall water splitting, the current density of 10 mA cm−2 can be delivered at an ultralow cell voltage of 1.50 V, which is among the lowest values of current non-precious metal catalysts. This work provides a unique strategy for exploring highly efficient heterostructure catalysts toward water splitting and beyond.