FeP/Ni2P nanosheet arrays as high-efficiency hydrogen evolution electrocatalysts

Abstract

Transition metal phosphides (TMPs) are attracting extensive attention as alternatives to noble metal-based electrocatalysts for hydrogen evolution reaction (HER). However, it is desirable and a long-term challenge to design and fabricate TMPs electrocatalysts for HER with high efficiency and durability. Herein, iron phosphide (FeP)/nickel phosphide (Ni₂P) nanosheet arrays supported on carbon paper (FeP/Ni₂P/CP) as a highly efficient electrocatalyst for hydrogen evolution is reported. The self-supported FeP/Ni₂P/CP catalyst exhibits superior hydrogen evolution reaction (HER) catalytic activity with low overpotentials of 51 mV and 122 mV in 0.5 M H₂SO₄, 46 mV and 98 mV in 1 M KOH to drive the current density of 10 and 100 mA cm⁻², respectively. Meanwhile, FeP/Ni₂P/CP exhibits good durability with negligible attenuation of current density for 50 h in both acidic and alkaline solutions. The combined experimental and theoretical study demonstrates the synergistic effect and modulation of electronic structure between FeP and Ni₂P, which endows FeP/Ni₂P with improved intrinsic activity. In addition, the increased accessible active sites and faster charge transfer rate collectively contribute to the enhanced prominent HER performance.