Piezoelectric-Induced Internal Electric Field in Bi2WO6 Nanoplates for Boosting the Photocatalytic Degradation of Organic Pollutants

The internal electric field induced by a piezoelectric effect is a promising method to suppress rapid electron-hole recombination of photocatalysis for environmental remediation. Herein, we fully utilized both piezoelectric and photocatalytic properties of Bi2WO6 nanoplates for the removal of organic pollutants. The degradation rate constant of piezo-photocatalysis is dramatically boosted to 0.077 min(-1) by the Bi2WO6 nanoplates, which is 4.2-fold of the photocatalysis alone. The superior catalytic activity of Bi2WO6 nanoplates was attributed to the accelerated electron-hole pair separation efficiency associated with the enhancement of the piezoelectric effect-induced internal electric field. Based on the theoretical calculation, the bandgap of Bi2WO6 nanoplates would decrease from 1.99 to 1.67 eV under mechanical strains, indicating that broader light harvesting and faster charge transfer can be achieved with the assistance of the piezoelectric field. Accordingly, multiple reactive oxygen species (center dot O-2(-) and center dot OH) are dominant for the degradation activity based on the quenching experiments and EPR analysis, outperforming piezocatalysis and photocatalysis. We have provided a new strategy to improve the catalytic decontamination performance.