Phosphorization engineering ameliorated the electrocatalytic activity for overall water splitting on Ni3S2 nanosheets

Abstract

Phosphorization engineering is an alternative method to explore highly efficient electrocatalysts for water splitting. Herein, a heterostructure consisting of Ni₂P and Ni₃S₂ supported on commercial nickel foam (Ni₃S₂–Ni₂P/NF) was prepared through the conversion of some Ni₃S₂ molecules into Ni₂P by phosphorization engineering. Electrochemical tests revealed that the partial phosphorization of Ni₃S₂ effectively enhanced the catalytic activity of the host electrocatalyst towards the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in 1 M KOH; in particular, the Ni₃S₂–Ni₂P/NF electrode exhibited the current density of 50 mA cm⁻² at the very low OER overpotential of 287 mV and needed the low overpotential of 130 mV to afford 10 mA cm⁻² for the HER. Moreover, the alkaline electrolyzer assembled by two Ni₃S₂–Ni₂P/NF electrodes could deliver 10 mA cm⁻² at the low voltage of 1.58 V and exhibited excellent durability during electrolysis for 15 h. Therefore, our study opens up an attractive fabrication strategy for highly active heterostructure electrocatalysts.