Porous (K0.5Na0.5)0.94Li0.06NbO3-polydimethylsiloxane piezoelectric composites harvesting mechanical energy for efficient decomposition of dye wastewater

Piezoelectricity as a physical property has received great attention due to its excellently functional applications, especially in piezoelectric catalysis and mechanical energy harvesting. To take full advantage of the functions of piezoelectric materials, (K0.5Na0.5)0.94Li0.06NbO3 (KNN6L) piezoelectric powders were compounded with polydimethylsiloxane (PDMS) in this work. The developed KNN6L-PDMS porous piezoelectric composites with flexible and recyclable characteristics could achieve ∼ 91% degradation rate of Rhodamine B (RhB) dye wastewater under mechanical vibration, and the outstanding piezocatalytic activity was still maintained after repeated decomposition multiple times. Besides, the relationship between piezoelectric potential and piezocatalysis was validated by COMSOL simulations. The content of piezoelectric powders played a positive effect on the magnitude of piezoelectric potential generated by the KNN6L-PDMS porous composites. Moreover, the catalytic mechanism was found to be originated by generation of various reactive oxygen species (mainly •O2- and •OH) in water environment as a result of strong piezoelectric effect by the porous composites. The porous piezoelectric composites with flexible and recyclable characteristics exhibited excellent performance in piezoelectric catalysis which has promising applications in the field of environmental remediation.