Metal phosphides are promising electrocatalysts for hydrogen evolution reaction (HER). However, their applications are hindered by the low electronic conductivity and sluggish HER kinetics in neutral electrolytes. Here we report an approach to significantly improving the HER performance of hierarchical iron phosphide (pFeP) modified with metallic iron (Fe) in neutral phosphate buffer electrolytes. It was observed that the presence of Fe can accelerate the charge transport kinetics. As a result, a significant improvement on the proton-acceptor (negatively charged P sites) and hydride-acceptor (coordinated Fe sites) was achieved, therefore promoting proton adsorption to the electrocatalyst surface during water electrolysis. Specifically, the Fe modified FeP electrocatalyst (pFe/FeP) displayed high HER catalytic rates (e.g., - 100 mA cm^-2 at an overpotential of - 380 mV), low onset potential (50 mV), and excellent long-term stability for 40 h in neutral electrolyte. This study provides a new approach to the design and synthesis of noble-metal-free electrocatalysts with excellent performance for hydrogen production in neutral electrolytes.

金属磷化物是有希望的氢释放反应（HER）电催化剂。然而，它们的应用由于中性电解质中的低电子电导率和缓慢的HER动力学而受到阻碍。在这里，我们报告了一种方法，可显着改善中性磷酸盐缓冲电解质中用金属铁（Fe）改性的分级磷化铁（p FeP）的HER性能。观察到Fe的存在可以加速电荷传输动力学。结果，实现了质子受体（带负电的P位）和氢化物受体（Fe的配位）的显着改善，因此在水电解期间促进了质子吸附到电催化剂表面。具体而言，铁改性的FeP电催化剂（pFe / FeP）显示出较高的HER催化速率（例如，在-380 mV的超电势下为-100 mA cm ^-2），低的起始电势（50 mV）以及在中性电解质中40 h的出色长期稳定性。这项研究提供了一种设计和合成具有优异性能的无贵金属电催化剂的新方法，该催化剂在中性电解质中能产生氢气。