Piezo-Phototronic Coupling Effect in CuBi2O4/AgNbO3 Z-Scheme Heterojunction for High-Efficiency Decomposition of Organic Dye

Silver niobate (AgNbO3) has been widely studied as a new photocatalyst for the degradation of organic pollutants. However, the fast recombination of photoinduced carriers in AgNbO3 material and its wider band gap are the main factors that restrict the improvement of its photocatalytic performance. Herein, the construction of heterojunction and polarization engineering as effective strategies were used to modulate the migration and separation of photoinduced carriers. CuBi2O4/AgNbO3 Z-scheme heterojunction was successfully designed and fabricated, and its outstanding piezo-photocatalytic performances have been demonstrated. CuBi2O4/AgNbO3 composites exhibited better degradation performances for RhB solution under visible light irradiation than individual AgNbO3. Inspiringly, the RhB could be completely degraded within 60 min by the P-10%CuBi2O4/AgNbO3 composite under ultrasonic-assisted illumination, and its reaction rate constant reached 0.0577 min–1, which is 3.52 times that of AgNbO3 (0.0164 min–1). The synergistic effects of heterojunction, polarization engineering, and ultrasonic vibration in the CuBi2O4/AgNbO3 composite were confirmed, and the piezo-phototronic coupling effect in the polarized CuBi2O4/AgNbO3 heterojunction significantly enhanced carrier separation, thereby promoting piezo-photocatalysis for organic dye. This work provides broad prospects for enhancing photocatalytic/piezo-photocatalytic performance by combining a narrow band gap semiconductor with ferroelectric materials.