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. [ABSTRACT FROM AUTHOR]