Carbon Nanofibers Catalysts with Ultra-Low Content High Entropy Metal Phosphide Inspired by Bitter Melon for Highly Efficient Water Electrolysis and Hydrogen Evolution

High entropy metal phosphide (HEMP) has great potential as an electrocatalyst due to the beneficial features of high entropy alloy synergy and the controllable structure and high conductivity of phosphides. Here, we innovatively use electrospinning and in situ phosphating to prepare three-dimensional (3D) networks of self-supporting HEMP nanofibers with varying degrees of phosphating. Comprehensive characterization employing XRD, XPS, and density functional theory calculations confirms that the introduction of phosphorus atoms in HEMP CNFs mediates the electronic structure, leading to lattice expansion and tensile strain, which in turn enhances the HER catalytic performance. Electrochemical measurements demonstrate that the HEMP-0.75 catalyst with an ultra-low loading of 1.22 wt% Ru exhibits the highest HER catalytic activity and stability in a 1 M KOH electrolyte, achieving a minimal overpotential of 26 mV at a current density of 10 mA cm−2 and a Tafel slope of 50.9 mV dec−1.