Porous FeP supported on 3D nitrogen-doped carbon fibers as efficient electrocatalysts for wide-pH hydrogen evolution

Abstract

A novel porous iron phosphide (p-FeP) loading on nitrogen-doped carbon fiber/carbon paper (p-FeP/NCF/CP) as highly effective self-supporting catalysts for the hydrogen evolution reaction (HER) is synthesized by a three-step approach, including N-doped carbon fiber network preparation, porous FeOOH/NCF/CP precursor by selectively etching, and subsequent phosphorization process. The as-obtained p-FeP/NCF/CP composite exhibits a higher specific surface area and larger porosity in comparison to FeP/CP composite due to the rich porous structure and 3D network of the N-doped carbon fiber matrix (NCF). Electrochemical measurements demonstrate that p-FeP/NCF/CP composite exhibits an excellent electrocatalytic activity for HER with small overpotentials of 63 mV and 96 mV at 10 mA cm⁻² current density in 0.5 M H₂SO₄ and 1.0 M KOH, respectively. The p-FeP/NCF/CP material also exhibits a small Tafel slope and charge transfer resistance as well as good stability and durability in pH 7 and pH 14.