Multi-modal energy harvesting for efficient piezoelectric photocatalytic pollutant degradation using CaBi4Ti4O15/BiOI heterojunctions with excellent piezoelectric properties

Bismuth-based materials, known for their unique layered structure, have emerged as promising candidates for semiconductor photocatalysts. However, their practical application is often hindered by wide band gaps and limited visible light absorption, leading to low photocatalytic efficiency. To address these challenges, we developed a novel CaBi₄Ti₄O₁₅/BiOI (CBTO/BOI) heterojunction catalyst, leveraging the synergistic effects of piezoelectricity and photocatalysis. The heterogeneous structure of CBTO/BOI, combined with the intrinsic polarization effect of CBTO, significantly enhances the separation of electron-hole pairs, providing a robust driving force for catalytic degradation. This multi-modal catalytic process efficiently harnesses both solar and mechanical energy, enabling rapid carrier separation and migration. Under simultaneous light and ultrasonic irradiation, the CBTO/BOI catalyst achieved an exceptional 98.36 % degradation of Rhodamine B (RhB) within 16 min, with a remarkable rate constant of k = 0.2298 min⁻¹, surpassing most reported piezoelectric photocatalysts. This study not only presents a highly efficient and environmentally friendly approach for pollutant degradation through multi-modal energy harvesting but also opens new avenues for the design of advanced photocatalysts for sustainable environmental remediation.