Scalable and Customizable Single‐Atom Coatings for pH‐Universal H 2 O 2 Electrosynthesis

ABSTRACT Achieving scalable fabrication of robust and uniform single‐atom catalyst‐based gas‐diffusion electrodes (SAC‐GDEs) remains challenging. Here, a universal one‐step soot‐deposition route was developed to convert various metal‐containing paraffins into conformal single‐atom catalyst (SAC) coatings on diverse electrodes (1D fibers, 2D plates, and 3D foams). The process provides multiscale control, from precursor‐defined molecular coordination to micropore wettability and macroscopic geometry, to collectively engineer hierarchical coating films that couple intensified mass transfer and high intrinsic catalytic activity for efficient H 2 O 2 electrosynthesis. As a device‐level demonstration, Pd‐SAC‐GDE delivers pH‐universal H 2 O 2 production under an industrial‐level current (500 mA cm −2 ) for 100 h, achieving a record‐high H 2 O 2 yield of 16.9 mol g −1 h −1 . A tip‐enhanced mechanism was proposed based on constant‐potential calculations. The results reveal that the curvature‐enhanced localized electric field promotes O 2 polarization and activation at the Pd‐O 3 sites, thereby facilitating both * OOH generation and adsorption and ultimately leading to highly selective H 2 O 2 production. This facile, broadly applicable fabrication strategy significantly advances the scalable manufacture of SAC‐coated GDEs for environmental and sustainable catalysis.