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

Abstract 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.