Integrated piezo-photocatalysis of electrospun Bi4Ti3O12 nanostructures by bi-harvesting visible light and ultrasonic energies

Co-utilization of solar and mechanical energies via the piezo-phototronic effect is a new-emerging strategy for the implementation of catalysis. Herein, a coupling among piezoelectricity, semiconductor, and photoexcitation of Bi4Ti3O12 nanostructures (BiTO NSs) to enable a high piezo-photocatalytic activity is demonstrated. Under the advantages of improving carrier density and suppressing the carrier recombination, the electrospun BiTO NSs calcined at 600 °C exhibits a superior piezo-photocatalytic performance with a Rhodamine B degradation rate of 0.071 min−1 that is 2.5-fold and 6.7-fold for the piezocatalytic and photocatalytic solos, respectively. The high piezo-photocatalytic performance is comprehensively ascribed to several properties, including high surface area, small crystal size, suitable energy band, large piezoelectric polarization, and rich oxygen vacancy. Furthermore, by bi-harvesting the visible light and ultrasonic energies, BiTO NSs can efficiently produce superoxide and hydroxyl radicals that are responsible for the dye degradation. This work provides a new strategy for developing high-performance catalysts and sheds new insights into the piezo-photocatalysis.