Self-supported Hierarchical Fe(PO₃)₂@Cu₃P nanotube arrays for efficient hydrogen evolution in alkaline media

Developing high-efficient and Earth-abundant electrocatalysts toward hydrogen evolution reaction (HER) is strongly desired for electrochemical water splitting but remains a considerable challenge. Herein, we propose a 3D hierarchical Fe(PO₃)₂@Cu₃P heterostructure nanotube arrays on Cu foams for promising HER catalysts. The HER performance can be tuned by changing FeCl₃ concentrations and the optimized cathode exhibits excellent HER activity in 1 M KOH with a low overpotentials of 108 mV @ 10 mA cm⁻² and a small Tafel slope of 84 mV dec⁻¹. Furthermore, this electrode delivers high electrochemical durability with stable operation for 24 h. Such high performance can be ascribed to the unique hierarchical heterostructure with large electrochemical surface area, synergistic effect and fast electron transport. Our study can provide new inspiration for rational construction of copper-based hierarchical nanomaterials for HER electrodes and other energy-related applications.