Significantly enhanced the light absorption and charge separation of BiNaTiO by coupling with CdS for high-performance piezo-photocatalysis.

Sodium bismuth titanate (BiNaTiO, BNT) is a typical lead-free piezoelectric material with perovskite structure, which exhibits great potential as piezo-photocatalyst but limited by the little response on visible light and insufficient carriers for efficient catalytic reactions. Herein, a novel BNT/CdS heterojunction was facilely synthesized by the two-step hydrothermal process for significantly enhanced piezo-photocatalytic degradation of organic dyes. The CdS nanoparticles with 35 nm in diameter are uniformly decorated on the highly crystallized BNT spheres. The obtained BNT/CdS heterojunction displays strong absorption of visible light because of the narrow band gap of CdS. Due to the strong built-in electric field under ultrasonic and efficient excitation by visible light, the photogenerated carriers can be efficiently separated at the BNT/CdS interface and migrate to the surface for catalytic reactions. As a result, the BNT/CdS shows much higher piezo-photocatalytic activity than that of BNT and can degrade 99% RhB within 60 min. Meanwhile, the piezo-photocatalytic performance of BNT/CdS is far better than that of individual photocatalysis or piezocatalysis. Moreover, the catalytic experiments in the presence of different scavengers indicate that ·O is the predominant active specie. The synthetic process is simple, low-cost, and controllable to produce high-performance BNT/CdS and is believed to show promising application prospect.