Nano-Needle-like Copper-Doped Iron Phosphide as a High-Performance and Cost-Effective HER Catalyst for Water Electrolysis

Abstract

Hydrogen production via water electrolysis has garnered significant attention as a pivotal technology for green energy conversion. In this work, cheap metal ions copper and iron are used as catalyst raw materials to develop high efficiency and low cost HER catalyst. Copper-doped iron phosphide supported on carbon paper (Cu-FeP/CP) is synthesized via a simple two-step process involving hydrothermal growth followed by high-temperature phosphidation. The morphology and electrochemical performance of iron phosphide catalysts with controlled copper doping are investigated. A nano-needle-like Cu-FeP/CP structure with 3% Cu doping exhibits a high surface area, providing abundant active sites, while Cu-induced charge redistribution and Fe-Cu synergy further enhance its intrinsic catalytic activity. HER catalytic performances results reveal Cu-FeP/CP-3% electrode exhibits low overpotentials of 71 mV in 0.5 M H₂SO₄ and 123 mV in 1 M KOH to achieve a current density of 10 mA cm⁻², along with small Tafel slopes of 49 mV dec⁻¹ and 72 mV dec⁻¹, respectively. Additionally, Cu-FeP/CP-3% shows low charge transfer resistance and stable HER performance over 24 h. The result provides new insights into the design and fabrication of highly efficient and cost-effective HER catalysts.

Graphical Abstract