Polydopamine‐Modified BiOX with Interfacial p‐Orbital Coupling Enhances Superoxide Conversion for Efficient Piezocatalytic H₂O₂ Production

Hydrogen peroxide (H 2 O 2 ) production via piezocatalysis offers a sustainable route to convert mechanical energy into chemical oxidants using water and oxygen. However, its efficiency is limited by sluggish surface redox kinetics, particularly the conversion of key radical intermediates (•O 2 − and •OH), and by the kinetic mismatch between charge carrier transfer and proton availability. Here, a polydopamine‐modified bismuth oxide halide (BiOX, X = Cl, Br, I) catalyst is reported that achieves a high piezocatalytic H 2 O 2 production rate of 3083 µmol g −1 h −1 and maintains stable activity across a broad pH range (3–9). Spectroscopic analyses and density functional theory calculations reveal that the polydopamine layer introduces interfacial p‐orbital interactions between carbon (from polydopamine) and bismuth sites, which enhance O 2 adsorption, lower the energy barrier for •O 2 − to •OOH conversion, and accelerate water oxidation for proton supply. This synergistic modulation of radical reaction pathways enables efficient and selective H 2 O 2 generation. The as‐produced H 2 O 2 demonstrates practical utility in pollutant degradation and antimicrobial applications. These findings establish a rational strategy for designing piezocatalysts by engineering interfacial orbital coupling to control reaction intermediate dynamics.