Piezo-photocatalysis over phase-engineered MoSe2 modified Bi2WO6 hierarchical microspheres: Utilizing piezoelectric effect to enhance photocatalytic performance

Photocatalysis technology is regarded as a promising way to ease the energy crisis and develop the sustainability of human society. However, the photocatalytic performance still suffers from critical charge recombination due to insufficient driving force. Herein, piezocatalysis and photocatalysis are judiciously combined to enable efficient piezo-photocatalytic activity, by synthesizing novel 1T/2H MoSe 2 /Bi 2 WO 6 (1T/2H MS/BWO) and 2H MoSe 2 /Bi 2 WO 6 (2H MS/BWO) hierarchical microspheres. The optimal 1T/2H MS/BWO piezo-photocatalyst exhibits excellent degradation activity of diclofenac (DCF) under the combined action of sunlight and ultrasound, achieving degradation efficiency of 99.9% in 60 min, which is significantly promoted than that of 2H MS/BWO and pure BWO. Piezoresponse force microscopy and ferroelectric analyzer results demonstrate that the 1T/2H MS/BWO composite generates a strong polarization electric field, which could act as powerful driving force to accelerate carriers separation and thus improve the piezo-photocatalytic activity. Moreover, several characterizations of 1T/2H MoSe 2 and 2H MoSe 2 reveal that the 1T/2H MoSe 2 displayed larger surface area, better light absorption, more active sites and more favorable band position than 2H MoSe 2 . Finally, mechanism studies including degradation pathways and possible intermediates during DCF degradation were investigated by density functional theory (DFT) calculations and liquid chromatography-mass spectrometry (LC-MS). • A novel 1T/2H MoSe 2 /Bi 2 WO 6 piezo-photocatalyst was fabricated. • The degradation efficiency of DCF over 1T/2H MS/BWO reached 99.9% in 60 min. • The piezo-photocatalytic mechanism of 1T/2H MS/BWO was rational proposed.