Bi2ZnB2O7 – PVDF electrospun composite membrane for waste water treatment utilizing photo-piezocatalysis

•The piezoelectric properties of the PVDF has been improved by incorporating Bi2ZnB2O7 via electrospinning method.•Electrospun nanofibers exhibit high mechanical strength and a favourable nanoconfinement effect on interfaces, which promotes the synergistic piezo-phototronic effect in piezoelectric heterostructures.•Achieved 74% degradation with a kinetic rate of 7.3 × 10−3 min−1 of methylene blue under combined effect of visible light irradiation and ultrasonication.•The mechanism underlying piezo-photocatalytic dye degradation has been explained with scavenger test.