Stabilizing Cationic Palladium Single‐Atom Sites on Heteroatom‐Doped Carbon for Selective Hydrogen Peroxide Electrosynthesis

Abstract Single‐atom catalysts (SACs) offer significant potential for the sustainable electrosynthesis of hydrogen peroxide (H 2 O 2 ) via the two‐electron oxygen reduction reaction (2e − ORR). However, their practical deployment is hindered by challenges related to limited operational stability and intricate synthetic procedures. Here, a family of cationic Pd single‐atom complexes anchored on nitrogen‐, sulfur‐, and dual N,S‐doped hollow carbon spheres (HCS) is reported, prepared via mild vapor‐phase doping combined with wet impregnation of Pd(acac) 2 . Systematic tuning of the heteroatom environment enables precise control over the Pd electronic state and local coordination, enhancing selectivity and long‐term stability under acidic, peroxide‐rich conditions. Operando ICP‐MS and advanced spectroscopy reveal that sulfur‐doping induces favorable charge redistribution, reinforcing Pd–support interactions and suppressing demetallation, while nitrogen doping enhances ORR activity. Notably, dual N,S‐co‐doping achieves a synergistic balance between catalytic performance and stability. This strategy offers a rational design framework for robust ligand‐containing SACs, advancing sustainable electrocatalytic technologies well beyond H 2 O 2 synthesis.