Local Polarization Piezoelectric Electric Field Promoted Water Dissociation for Hydroxyl Radical Generation under Ambient Humidity Condition.

Abstract

Combining piezocatalysts with mechanical ball milling for dissociating water to generate hydroxyl radicals (·OH) offers unprecedented opportunities for energy conversion and environmental remediation. However, the in-depth insights into the relationship between water and local polarization piezoelectric electric field (LPPEF) are currently lacking, in particularly, the ·OH formation mechanism in ball milling driven piezocatalyst system is not systematically elucidated. To this end, the present work constructs a ball milling driven piezoelectric solid/liquid interface between piezoelectric Pb₂B₅O₉Cl (PBOC) and different contents of water to investigate LPPEF initiated catalytic reaction. Results show that PBOC exhibits an excellent Tetrabromobisphenol A (TBBPA) degradation efficiency with a 68.94 and 12.43 times faster rate constant than traditional SiO₂ and BaTiO₃, respectively. Under ambient humidity condition, the lower energy barrier of water dissociation (0.23 eV) endows ·OH generation more energetically favorable than under the water-oversaturated condition (0.66 eV), and trace water magnifies the polarizability of [BO₃] and [BO₄] units in PBOC to initiate an enhanced LPPEF, thus it enhances the trapping of lone pairs electrons in trace adsorbed water by holes to contribute a higher yield of ·OH. This study constructs a highly correlated field-initiated electron transfer system that provides opportunities for promoting the performance of piezocatalytic materials.