S and Co co-doped Cu3P nanowires self-supported on Cu foam as an efficient hydrogen evolution electrocatalyst in artificial seawater

In this work, we designed and fabricated S and Co co-doped metallic Cu3P nanowires self-supported on Cu foam (S&Co-Cu3P NWs/CF) for hydrogen evolution reaction in neutral condition. In the pH-near-neutral seawater electrolyte, the S&Co-Cu3P NWs/CF shows small overpotentials of 127.2 mV at 10 mA cm−2 and 248.2 mV at 100 mA cm−2 with a Tafel slope of 80.9 mV dec−1. It only shows 3.6% attenuation even after a 30 h test at − 0.2 V vs. RHE. The excellent activities of S&Co-Cu3P NWs for neutral HER can be attributed to the 3D nanowire—like porous structure with enhanced active sites numbers and the optimized electronic structure by heteroatoms doping. Moreover, the binder-free electrode improves the conductivity and stability. To verify the feasibility of seawater as a potential alternative neutral electrolyte, we analyzed the HER performances of the as-prepared catalyst in 1.0 M PBS and 0.5 M Na2SO4 solution. Compared with the HER performances in 1.0 M PBS electrolyte, only 6.2 mV and 4.6 mV dec−1 increases can be seen in artificial seawater for overpotential at 10 mA cm−2 and Tafel slope, indicating that it is a highly feasible strategy as an alternative of the neutral solutions. This work provides a sustainable and cost-effective option to generate green hydrogen by directly using seawater as electrolyte.