Bubble-triggered piezocatalytic generation of hydrogen peroxide by copper nanosheets-modified polyvinylidene fluoride films for organic pollutant degradation and water disinfection

Piezocatalysis has emerged as an attractive technology for environmental remediation by the effective transformation of mechanical energy into electrical energy. Herein, copper nanosheets-modified polyvinylidene fluoride films (CuNS/PVDF) are synthesized via a facile wet-chemistry route and exhibit a much-enhanced piezoelectric property, as compared to pristine PVDF. This is ascribed to CuNS that increases the stress response point and Young’s modulus of the PVDF host. Among the series, CuNS_4%/PVDF, with a 4 wt% loading of CuNS and a d₃₃ coefficient (39 pC N^-1) 2.6 times that of PVDF, exhibits the highest rate of H₂O₂ generation (163.3 μM g⁻¹ h⁻¹) by water oxidation in pure water under air bubbling, which is 3.7 times that of PVDF. This can be exploited for organic pollutant degradation and water disinfection, achieving a degradation rate of 99.8%, 98.37%, 89.02% and 81.60% for chlortetracycline hydrochloride, tetracycline, ofloxacin and ciprofloxacin, respectively, after 80 min's air bubbling, and 99.7% bactericidal efficiency against Escherichia coli after 12 h’s co-culture, along with excellent stability and recyclability. Notably, such a performance remains prominent in actual wastewater, seawater, tap water and other water environments. The reaction mechanisms are unraveled by the combined studies of spectroscopic measurements and theoretical calculations. Results from this work highlight the significance of structural engineering in enhancing the piezocatalytic activity of PVDF for water treatment and disinfection.