Intensifying Localized Polarization Piezoelectric Field via Tip Effect on Carbon Quantum Dots Modified Ca ₂ B ₃ O ₆ Cl for H ₂ O ₂ Production in Pure Water

ABSTRACT Piezocatalytic H 2 O 2 production from air and water is a promising sustainable strategy. However, sluggish electron transfer and high energy barriers for the formation of key intermediates severely hinder its efficiency. Herein, carbon quantum dots (CDs) modified non‐centrosymmetric Ca 2 B 3 O 6 Cl (CDs/CBOC) are demonstrated for piezocatalytic H 2 O 2 generation without sacrificial agents. Integration of CDs on the CBOC induces a significant tip effect, which concentrates piezoelectric charges and intensifies the localized polarization piezoelectric field (LPPF). Kelvin Probe Force Microscopy (KPFM) and COMSOL simulations confirm that this geometry‐driven field amplification multiplies interfacial potential and accelerates electron transfer. Moreover, in situ KPFM provides visualization of surface potential evolution, confirming a synergistic dual‐pathway mechanism. Time‐resolved ATR‐FTIR reveals a directional reorganization of interfacial water molecules into an ordered hydrogen‐bonding network for rapid proton transfer. Consequently, the CDs/CBOC‐2 achieves a remarkable H 2 O 2 yield of 1838.5 µmol g −1 h −1 in pure water, a nearly ninefold enhancement over pristine CBOC. Furthermore, the in situ generated H 2 O 2 drives a potent piezocatalytic self‐Fenton process, achieving nearly 100% degradation of conventional pollutants and an 80% defluorination rate for perfluorooctanoic acid (PFOA). This work offers a transformative strategy for modulating localized physical fields to optimize the kinetics of H 2 O 2 generation.