High-Period Element Doping as a Key Driver of Hydrogen Evolution in a Proton Exchange Membrane Water Electrolyzer.

Proton exchange membrane water electrolysis (PEMWE) is a promising strategy for sustainable hydrogen production, but its application is limited by the high cost and instability of catalysts under acidic operation conditions. Here, the study reports group VA element-doped graphitic nanoplatelets (XGnPs; X = N, P, or Sb) as effective supports to enhance both the activity and durability of electrocatalysts. The resulting platinum (Pt) nanoparticles on XGnPs (Pt@XGnPs) catalysts exhibit improved charge transfer to the metal and strong metal-support interactions. Among them, Pt@SbGnP exhibits the best performance, with a low overpotential of 15.3 mV at 10 mA cm-2 and a Tafel slope of 27.8 mV dec-1, surpassing commercial Pt/C. System-level testing further confirmed its superiority, achieving 68.2 mA cm-2 at 1.9 V with 96.6% Faradaic efficiency for two-electrode system and 1 A cm-2 at 1.724 V for full PEMWE system. Density functional theory calculations reveal that heteroatom doping modulates the charge transfer to the metal, facilitating efficient hydrogen evolution reaction (HER) kinetics.