Cu2S-Cu3P Nanowire Arrays Self-Supported on Copper Foam as Boosting Electrocatalysts for Hydrogen Evolution

With the rapid electrochemical development of hydrogen evolution, the search for low-cost and high activity electrocatalysts for hydrogen evolution has received extensive attention. The fabrication of self-supported Cu2S-Cu3P nanowire (Cu2S-Cu3P NW) arrays on a commercial copper foam by a liquid-solid reaction and subsequent phosphatation at low temperature is reported. The corresponding scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results indicate that the Cu2S-Cu3P NW arrays have a dense nanowire (NW) structure with sulfur and phosphorous uniformly distributed on the surface of the nanowires. Interestingly, the Cu2S-Cu3P NW arrays act as a hydrogen-evolving cathode that when operated in 1.0 m KOH electrolyte only require a low overpotential of 158 mV to achieve a current density of 10 mA cm(-2) and show a small Tafel slope of 45 mV dec(-1). The activity decrease is negligible after holding at -500 mA cm(-2) for 75 h, which thus demonstrates excellent stability. This could be due to the structure of nanowire arrays and synergistic effects between S and P, which could increase the specific surface area, reduce the charge transfer resistance, facilitate mass diffusion and electron transfers, and increase the active sites. This work therefore provides a simple method to prepare low-cost and self-supported electrocatalysts with high catalytic activity for hydrogen evolution.