Self-Polarized CNT/PVDF Nanocomposites with ultra-high β phase achieved via water induction for efficient piezo-catalysis

Polyvinylidene fluoride (PVDF) is promising for piezo-catalytic applications owing to its excellent biocompatibility, flexibility, and durability. However, it is limited by weak electroactivity originating from its intrinsically low β piezoelectric phase content (<20%) and insulating properties. Here, we achieve efficient piezo-catalysis by introducing a self-polarized PVDF-based composite containing carbon nanotube (CNT) as conductive fillers. Notably, our self-polarized CNT/PVDF (SCP) ensemble exhibits a high β phase content of ∼95%, which is up to 6-fold higher than the original PVDF powder, and superior electrical activity by exploiting the polarity induction effect of water molecules. As a proof-of-concept demonstration, the SCP realizes efficient degradation of organic-polluted water by at least 95% within 2 h of ultrasonication (240 W), even at high pollutant concentration (40 mgL⁻¹). Systematic investigations unveil its excellent recyclability and adaptability to various tropical or subtropical natural waters. More importantly, the SCP also achieves efficient H₂O₂ production of up to ∼13.5 mmol g_CNT ⁻¹ h⁻¹, which is > 6-fold and > 19-fold better than standalone self-polarized PVDF (i.e., without CNT content) and emerging piezo-catalytic designs, respectively. This study offers a unique approach for designing PVDF-based piezo-catalyst to expedite mechanically-driven catalysis towards practical applications.