Piezo-photocatalysis enhanced separation of charge carriers and catalytic performance in the Bi2MoO6/KNbO3 heterojunction

In this paper, a Bi2MoO6/KNbO3 photocatalyst with type-II heterojunction was designed and successfully prepared via a simple solvothermal method, and effect of loading amount of Bi2MoO6 in the composite on the piezophotocatalytic performance was studied in detail. The BMO/KN-3 composite loaded with 45 % Bi2MoO6 showed the highest 90 % piezo-photocatalytic degradation efficiency of RhB under the synergistic effect of illumination and ultrasound, and the degradation efficiency can still remain above 81.5 % after 5 times of reused. The piezophotodegradation efficiency of the BMO/KN-3 composite towards other pollutants such as MB, TC and CR also reached 76 %, 65 % and 97 % respectively. The free radical scavenging experiment confirmed that h+ plays a major role in the degradation process. Theoretical analysis suggests that the synergistic effect of type-II heterojunction construction and piezoelectric polarization under illumination in the Bi2MoO6/KNbO3 composite greatly promotes the separation of photocarriers at the phase interface, thereby leading to excellent degradation characteristics.