Bi-piezoelectric effect assisted ZnO nanorods/PVDF-HFP spongy photocatalyst for enhanced performance on degrading organic pollutant

Piezoelectric field engineering has been recently proved to restrain the photogenerated carrier recombination both in the bulk and on the surface of photocatalyst. Herein, we proposed a bi-piezoelectric ZnO nanorods (NR)/ PVDF-HFP spongy film that can utilize water flow vibration to boost the photocatalytic degradation of organic dye. The composite photocatalyst can be deformed by water flow to generate an integrated piezoelectric field from PVDF-HFP and ZnO NR, which can considerably drive the separation and transfer of photogenerated charge carriers in ZnO NR. As a result, the ZnO NR/PVDF-HFP spongy film shows a ~ 3 fold increase in reaction rate constant of degrading methyl orange (MO) with irradiation as flow speed increases from 200 rpm to 1000 rpm. A model about the bi-piezoelectric effect of ZnO NR/PVDF-HFP was configurated according to a series of characterization by piezoelectric force microscopy (PFM) and photoluminescence (PL). This work demonstrates the contribution of the bi-piezoelectric effect to photocatalytic water decontamination and provides a promising strategy to use dual-sustainable energy- solar and water energy.