Piezo-photocatalytic Activity of Bi0.5Na0.5TiO3@TiO2 Composite Catalyst with Heterojunction for Degradation of Organic Dye Molecule

The low-yield and high-recombination rate of carriers are the main factors that limit the efficiency of traditional piezocatalysis and photocatalysis. In this paper, the Bi0.5Na0.5TiO3@TiO2 composite catalyst with heterojunction was prepared and applied to obtain superior piezo-photocatalytic activity. On the one hand, the narrow band gap (2.77 eV) made it easy for the composite to excite photogenerated carriers under visible light. On the other hand, the piezoelectric field that originated from the bending deformation of Bi0.5Na0.5TiO3 effectively promoted the separation and migration of carriers. Driven by ultrasonic vibration and visible light irradiation, the poled composite catalyst degraded over 97% of RhB dye solution through piezo-photocatalytic effect in 90 min. Compared with pure BNT and TiO2, the enhanced catalytic performance of the BNT@TiO2 composite indicated the superiority of the heterojunction.